Class 6 Biology - BeTOPPERS NEET Foundation Series - 2022 Edition

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NEET FOUNDATION Class VI

BIOLOGY

© USN Edutech Private Limited The moral rights of the author’s have been asserted. This Workbook is for personal and non-commercial use only and must not be sold, lent, hired or given to anyone else.

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Published by

:

USN Eductech Private Limited Hyderabad, India.

PREFACE

Our sincere endeavor in preparing this study material is to enable students to effectively grasp and understand the concepts of IIT foundation. This study material has been compiled by our team of experts who have a decade of experience in various academic fields. These books also proved to be successful in developing of academic skills like concentration power, understanding ability, memory power, retention ability, problem-solving skills, application skills, analytical ability, logical thinking and emotional strengths like interest in learning, self-reliance, confidence, will power, psychological strength, right stir and zeal and physical stamina. The important features of the books are: 1.

Lucidly presented concepts For easy understanding of the concepts, they are presented in simple and easy, comprehensible language. 2. Learning Outcomes Each chapter starts with Learning outcomes which precisely conveys what the students is going to learn in this chapter. 3. Bold-faced key terms The key words, concepts, definitions, formulae, statements, etc., are expressed in bold face, indicating their importance in the content. 4. Tables and charts Numerous strategically placed tables and charts, list out and summarize the important information, making it readily accessible for effective study. 5. Box items Throughout the text, the box items highlight special topics that take the text material to be a more extended level. Students will find them to be a lively and interesting feature as they investigate the subject. 6. Photographs A wide array of visually appealing and informative photographs are used to help the students to understand various phenomena and inculcate interest in the subject. 7. Illustrations Because a picture is worth a thousand words, each chapter has ample number of illustrations that clarify different concepts and enhance learning. 8. Flow diagrams To help students understand the steps in problem-solving, flow diagrams have been included at key locations i.e., at important concepts. These diagrams allow the students to visualize the process of solving a problem. 9. Summary charts At the end of the chapter or important concepts, there is a summary of major concepts covered. Each section is reviewed in a paragraph form. The summary, along with the blueprint, provides a complete overview of the chapter. 10. Concept-wise Formative Worksheet Unlike other books, this book contains concept-wise Formative Worksheet problems. The solutions for these problems shall be discussed by the teacher in the classroom. These questions allow the child to strengthen understanding and application skills.

11. Concept-wise Conceptive worksheet Each Formative Worksheet is followed by a Conceptive worksheet. This contains additional problems of the respective concepts. The problems are expected to be solved by the students for additional practice. This allows the students to get exposed to new style of problems related to the concept. 12. Summative worksheet At the end of each chapter, there is a Summative Worksheet. This worksheet contains problems based on all the concepts of the chapter. Unlike Formative Worksheet and Conceptive Worksheet problems, the problems in this section involve the application of multiple concepts of the given chapter. The worksheet allows the child to strengthen the problem-solving, application and analytical skills. 13. Advanced worksheet Each Summative Worksheet is followed by an HOTS (Higher Order Thinking Skills) worksheet. This worksheet contains problems of advanced type involving Higher Order Thinking Skills. The concepts can be of same chapter or different. The solving of these problems prepares the child to face new patterns of problems that appear in actual IIT and other entrance examinations. Strengthening of all the academic skills of a child is the main objective of this worksheet. 14. IIT JEE worksheet Finally, every chapter ends with a IIT JEE worksheet. This worksheet contains the problems which have appeared in various competitive examinations like IIT, AIEEE, KCET, TCET, JIMPER, BHU, AIIMS, PbCET, CBSE, CET, etc related to the chapter. This part of the worksheets creates awareness and builds confidence as the students get exposed to real problems that appeared in various competitive examinations. 15. Wide variety of problems The problems included in the worksheets cover various models that appear in different competitive examinations. The different models include:

 Non-objective type  Objective type with more than one option correct  Matching type – II (Three columns)  Statement type – II (More than two statements)  Statement and Explanation type  Figurative type  Road Map type

 Objective type with single option correct  Matching type – I (Two columns)  Statement type – I (Two statements)  Assertion and Reason type  True or False type  Comprehensive type  And many more……

We would like to thank all members of the different departments of BeIITIIANS who played a key role in bringing out this student-friendly study material. We sincerely hope that this study material will prove useful to the students undergoing IIT foundation, ensuring their success in various competitive examinations. However, We believe that as there is always scope for improvement, we value constructive criticism of the subject matter, as well as suggestions for improving the book. All suggestions will be duly incorporated in the next edition. Wish you all the best. Academic Team USN Edutech

CONTENTS 1.

Life on Earth

..........

01 - 14

2.

Classification of Living Beings

..........

15 - 32

3.

Soil

..........

33 - 42

4.

Fossils

..........

43 - 50

5.

Structure and Functions of Plant Parts

..........

51 - 76

6.

Health and Hygine

..........

77 - 92

7.

Our Environment

..........

93 - 132

8.

Key and Answers

..........

133 - 140

Learning Outcomes



List the life processes common to all living organisms



Differentiate between plants and animals



Recognise the cell as the basic unit of life



Understand micro-organisms

Characteristics of the Living Chapter -1

By the end of this chapter, you will understand  Differentiate between a living organism and a non-living object

Life on Earth

1. WHAT IS LIFE? There are millions of different things in the world around us. Some of them are alive and some are not. People, cats, mice and flowers are alive, but rocks, water, chairs and tables are not. How can you tell a living thing from something that is not alive? In this chapter, we will study the characteristics of the living things, so that we can answer this question. Also, whether there are any common features between living and nonliving things? Let us look at the following Fig. 1.1.

Figure 1.1 : Comparison of activities in a plant and a stone What does it show? It shows comparison between a plant and a stone. This comparison also shows that these two objects differ in some respects; A stone cannot move on its own, does not eat food, cannot grow or produce more of its type. On the other hand, a plant shows all these features — it can move by itself, it can feed itself; it grows and produces more of its type (reproduces). What will you find if you make comparison between an animal like a dog and the stone?

2. COMMON FEATURES OF LIVING AND NON-LIVING THINGS 

All these things possess mass, shape and occupy space.



Both the living and the non-living things have a structural unit - cells in the living and molecules in the non-living things.



Cells do not exist in non-living things.

Life on Earth

2

3. DIFFERENCES BETWEEN LIVING AND NON-LIVING THINGS Life is something special and unique. All we can do to define 'life' is to describe the observable processes or phenomena or features that distinguish living matter from non-living. Non-living things may perform one or more of these processes. For example, a crystal can 'grow', and a machine can 'move', but it is only a living organism that can perform and exhibit all the characteristics given below. 4 CHARACTERISTICS OF THE LIVING 1. CELLULAR ORGANISATION   





All living things are made up of cells (Fig. 1.2). A cell is the basic unit of life. Some living things consist of only a single cell. For example, Amoeba, yeast, and bacteria. Such living things are called unicellular organisms. Most living things, however, are made up of millions of cells. They are called multicellular organisms. For example, mango plant, rose plant, pea plant, man, housefly, dog and cat. Cells helps in carrying out various functions like nutrition, respiration, excretion etc. They are called the Figure 1.2: Cells in living beings. structural and functional units of organisms.

2. NUTRITION          









Food is required by all living things. Food provides us energy so that we can perform different activities during the day. Food also helps in body growth as well as its maintenance and repair. Animals obtain ready-made food in the form of milk, bread, wheat, eggs, meat, pulses, fruits and vegetables. Green plants can prepare their own food. They obtain water and minerals from the soil. Roots help the plants in this job. Roots, in addition, perform another role of fixing the plant to the soil. For preparing their food, plants also require carbon dioxide. This is absorbed from the atmosphere (air) by the leaves through minute pores (called stomata) present on their surface (Fig. 1.3). The green plants utilize (i) carbon dioxide from air, (ii) water and minerals from soil, and (iii) sunlight to prepare their food. This process of food preparation or Figure 1.3: Presence of minute pores on manufacture is called photosynthesis. leaf surface. As the green plants can prepare their food, they are called autotrophs (auto-self; troph = food) and the mode of nutrition is called autotrophic nutrition. Animals, on the other hand, obtain ready-made food either from plants (wheat, pulses, fruits, vegetables and grass) or other animals (milk, eggs, meat). Animals, therefore, are called heterotrophs (hetero = other; troph = food) since they cannot prepare their food, and the mode of nutrition is called heterotrophic Figure. 1.4: Animal eating grass. mode of nutrition (Fig. 1.4).

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3. RESPIRATION   

All living things respire. That is, they take in or breathe in oxygen from the air and give out carbon dioxide. The oxygen is used to produce energy from the food consumed by the organisms. The energy thus produced is utilised to perform various activities by the living beings.

4. GROWTH      

Growth is a permanent and irreversible process. All living things grow from a single cell into an adult organism made up of billions of cells. The pattern of growth, however, is different in plants and animals. All living things grow, whereas non-living things do not grow. Growth, if present, in non-living things is external as it takes place by adding matter externally and it is reversible. Growth in living things takes place by the addition of new body material called protoplasm, and is thus internal.

Figure 1.5: Growth of a baby into an adult Growth is a permanent and irreversible increase in the weight and volume of an organism. In short, growth means to become bigger and more complicated. 5. EXCRETION    

Excretion is the removal of waste materials from the body. Accumulation of waste materials is harmful for the body. Waste materials are excreted mainly in the form of urine, sweat and carbon dioxide by the living animals. In case of plants, carbon dioxide and water vapour are excreted from small pores in their leaves.

Excretion is the removal of waste materials that are produced as a result of the different activities which take place inside the body of an organism. 6.   

REPRODUCTION All living organisms have the ability to produce young ones of their own kind (Fig. 1.6). For example, a cat produces kittens who grow into adult cats. A hen lays eggs which hatch into chicks, finally producing hens or roosters. A mango tree bears fruits which possess seeds. The seed develops into a young seedling and in due course of time, into a tree. This means that living things can make more of their own kind.

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Life on Earth 

4

It is to be noted that non living things like table, stone, etc never reproduces like living things.

Figure 1.6: Reproduction in (a) a plant (b) a bird Reproduction is the ability to produce young ones of their own kind. It is necessary for organisms to survive generation after generation. 7. MOVEMENT  

 



 

Living things show movement. Every day you see the animals, birds and insects moving from one place to another. Such a movement is called locomotion. Most plants are fixed to the soil. They are unable to carry out locomotion but show movement. In plants, the stem moves towards light (Fig. 1.7), the roots grow downwards in the soil in search of water and in sunflower plant, the flowers change their position to face the sun. In small microscopic plants like the alga Chlamydomonas, the whole plant moves about in water.

Figure. 1.7: Movement of plant parts (shoot) towards sunlight (phototropic)

Some animals like sponges, corals and sea-anemones do not move from place to place (Figs. 1.8, 1.9). For obtaining food, hydra and sea-anemone have long structure called tentacles around their mouth.

Figure 1.8: hydra

Figure 1.9 sea-anemone

Movement of animals from one point to another is called locomotion. Plants do not show locomotion. 8. RESPONSE TO STIMULI (SENSITIVITY) 

Living things respond to stimuli or changes in their surroundings.

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6th Biology



In cold weather, we wear woolen clothes. If our hand touches a hot object, we respond by quickly withdrawing it. A plant bends towards sunlight (phototropic). Roots grow downwards in the soil (geotropic). In sensitive plant, the leaves curl up on being touched by hand (Fig. 1.10). Animals like cockroach and earthworm move away from light. In all these examples, responses are taking place. A response is an action which occurs as an answer to a particular stimulus. For instance, cold weather, hot object, sunlight and gravity are stimuli, as a result of which respective responses like wearing of woolen clothes, withdrawal of hand, bending of plants, downward growth of roots and moving away of animals takes place

  

 

Figure 1.10: when you touch the leaves of this plant, they will suddenly curl up. It is known as a sensitive plant. Living organisms are able to respond to changes in their surroundings. The organism detects a stimulus from the surrounding and produces a response to that stimulus.  Anything which produces a response in an organism is called stimulus.  A response is an activity in the living body that results from a stimulus. 9. LIFE CYCLE     

Living things follow a life cycle. They start their life from a single cell. In animals, the life cycle consists of birth, growth, reproduction and death. In plants, life cycle begins through seeds or spores. The life cycle of an organism may take a few hours, a few days or hundreds of years to complete. The period during which an organism completes its life cycle is called its life span. For example, in bacteria, the life span is very short. Table 1.1: Life span of some organisms Organism Life span 1. Bacteria 20 minutes 2. Pea 4 months 3. Pine tree Several years 4. House fly 1-4 months 5. Mouse 2-3 years 6. Dog 16-18 years 7. Lion 20-25 years 8. Elephant 70-90 years 9. Humans 60-80 years 10. Tortoise 120-150 years

THINK IT OVER| Are There Things In Between Living And Non Living Yes, the viruses are such entities existing in the universe. Viruses grow and multiply only when they are inside living things like man. Outside living bodies, they are lifeless and are just like crystal.

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Life on Earth

6

Table 1.2: Differences between living and non living things 1. Cellular Organisation

Living Things Are made up of cells.

Non-living Things Lack cellular organisation.

2. Nutrition

Require food for growth and development.

Not required.

3. Respiration

Show respiration.

No respiration.

4. Growth

Is permanent and irreversible.

Lack growth; even if present it is reversible.

5. Excretion

Removal of waste materials takes place.

No excretion.

6. Reproduction

Takes place.

No reproduction.

7. Response to stimuli (responsiveness)

Present.

Absent.

8. Life cycle

Consists of birth, growth, reproduction and death.

Lack a life cycle.

5. STUDY OF LIVING THINGS – BIOLOGY     



The study of living things or life is called biology. The word comes from two Greek words: bios, meaning 'life', and logos, meaning 'a study'. Today, biologists, people who study biology, are interested in understanding the relationships that exist between man and millions of living things that surround him. They want to know what effect these living things have on man's own development and the environment around. They fathom the icy depths of the oceans and scale the peaks of the tallest mountains. They find their way through thick jungles, and peer for hours into sophisticated instruments, in order to get at the mystery of life. Biology has two main divisions : (i) botany, which deals with plants; and (ii) zoology dealing with animals.

6. MICRO-ORGANISMS Some living organisms are very small in size and most of these are too small to be seen with the naked eye. These can be seen with the help of an instrument called microscope. Such tiny organisms are called micro-organisms or microbes. Microorganisms occur both in plants and animals. Examples : Bacteria, some fungi (like yeast, Aspergillus, Penicillium), some algae (like Chlamydomonas, Oscillatoria, diatoms), and some protozoans (like Amoeba, Plasmodium). While bacteria, algae and fungi belong to plants, protozoans are animals. 7. DIFFERENCES BETWEEN PLANTS AND ANIMALS 1. NUTRITION      

Most plants are green in colour as they possess a pigment called chlorophyll, in them. They can manufacture their own food using carbon dioxide, water and sunlight. This process of food manufacture is known photosynthesis, and the mode of nutrition is called autotrophic. Plants, being autotrophic, are also called producers. Animals, do not have chlorophyll, so they cannot prepare their own food. They depend on plants or other animals for their food. For this reason, animals are called consumers, and the mode of nutrition is heterotrophic.

2. LOCOMOTION    

Plants, being fixed to the soil, do not move from place to place. They lack organs for locomotion. Animals, on the contrary, move from place to place in search of food and shelter. They also possess organs for locomotion such as legs, wings, etc.

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6th Biology

 

Some plants, too, can move, but only very slowly. Daisies and other flowers move their petals when they close them at night and open them in the morning. Leaves of some plants like touch-me-not suddenly curl up on being touched. Some plants like utrlicularia, nepenthes, trap insects.

 

3. GROWTH    

Plants have unlimited growth. In simpler words, it means that they can grow throughout their lives. Further, the growth is restricted or localized to certain fixed regions of the plant body such as the root tip and the shoot tip. Animals, however, grow up to a certain age only and stop growing thereafter. Moreover, they do not possess fixed growing points, and the growth is diffused throughout the body.

4. CELL STRUCTURE   

Plant cells are surrounded by a rigid cell wall. Cell wall is lacking in case of animal cells. Also, inside the plant cell are structures called chloroplasts. contain the green pigment, chlorophyll, providing green colour But the animal cell lacks chloroplasts (Fig. 1.11).

Figure 1.12: Cell structure Table 1.3: Differences between Plants and Animals. Plants

Animals

Nutrition : Most plants can manufacture their own food (they contain a green pigment called chlorophyll) — autotrophic in nutrition.

Animals cannot make their own food (lack chlorophyll) — heterotrophic in nutrition.

Locomotion: They are generally fixed to the soil; lack organs for locomotion.

Show locomotion; possess organs for locomotion.

Growth: Growth is unlimited and localised.

Growth is limited and diffused.

Cell structure: Possess a cell wall; chloroplasts are present.

Lack a cell wall; chloroplasts are lacking.

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Life on Earth

8

SNAP SHOT 1. Living things exhibit certain characteristics that distinguish the living matter from non-living matter. These characteristics include cellular organisation, nutrition, respiration, growth, excretion, reproduction, movement and response to stimuli. 2. The science of study of living things is called 'biology'. Study of plants (botany) and animals (zoology) are the two main divisions of biology. 3. Micro-organisms are very small organisms which cannot be seen with the naked eye. 4. Plants and animals differ from each other in their nutrition, locomotion, growth pattern and cell structure. 5. In terms of cell structure, plant cells possess a cell wall and contain structures known as chloroplasts. Both these structures are absent from animal cells.

Fomative Worksheet 1.

Which of the following groups of things represents non-living things? (A) (B)

(C)

(D)

2.

3.

4. 4. 5. 6.

7.

Which of the following things is non-living? (A) Spruces (B) Rocks (C) Cats (D) Ants Which of the following statements is correct? (A) All these things possess mass, shape and occupy space. (B) Both the living and the non-living things have a structural unit - cells in the living and molecules in the non-living things. (C) Cells do not exist in non-living things. (D) All the above Which of the following is a unicellular organism? (A) Amoeba (B) Mango plant (C) Dog (D) Cow Which of the following is a multicellular organism? (A) Yeast (B) Bacteria (C) Amoeba (D) Rose plant The structural and functional unit of organisms is (A) Cell (B) Tissue (C) Organ (D) All Plants prepare their own food by the process of (A) Respiration (B) Excretion (C) Photosynthesis (D) Chemosynthesis In plants, the exchange of gases takes place through the stomata. During day time, they take up carbon dioxide and release oxygen for photosynthesis while during night time, the process gets reversed. Which of the following graphs correctly represents the effect of the duration for which stomata remain open on the amount of oxygen taken in?

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Oxygen obtained

(B) Oxygen obtained

(A)

Time

Time

Oxygen obtained

(D) Oxygen obtained

(C)

Time

8.

Autotrophs are (A) Plants

9.

(D) None

(B) Animals

(C) Both

(D) None

(B) Reproduction

(C) Respiration

(D) Excretion

The process of chicks becoming adult hen illustrates the phenomenon of (A) Growth

12.

(C) Both

Fishes taking in the oxygen dissolved in water through their gills illustrates the process of (A) Growth

11.

(B) Animals

Heterotrophs are (A) Plants

10.

Time

(B) Respiration

(C) Movement

(D) Reproduction

All living things exhibit growth. Which of the following examples illustrates the process of growth? (A) Closing of the leaves of touch me not plant on being touched (B) Breathing of air by earthworms through skin (C) Chicks becoming adult hen (D) Production of seeds by plants

13.

Living organisms exhibit characters like growth and reproduction. An increase in the size and weight of an organism occurs because of (A) Growth

14.

(B) Survival

(C) Reproduction

(D) Division

The given diagram represents changes that take place in the body of a chick after it emerges from the egg.

The process illustrated in the given diagram is called (A) Growth

(B) Excretion

(C) Respiration

(D) Movement

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Life on Earth

Size of organism

Which of the given graphs correctly represents growth in living organisms? (A) (B) Size of organism

15.

10

Time

Size of organism

(D) Size of organism

(C)

Time

Time

16.

17.

All living things grow. A chick grows into a small chicken which grows to become an adult hen.

Which of the following things can grow? (A)

(B)

(C)

(D)

All living things reproduce, i.e., they give rise to young ones. Which of the following figures is that of a non-living thing? (A) (B)

(C)

18.

Time

(D)

Which of the given animals is incorrectly matched with its young one? (A) (B)

(C)

(D)

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11 19. 20. 21. 22.

23.

24.

25. 26.

27. 28.

29.

30.

31. 32. 33. 34.

Which of the following removes waste material from the body? (A) Nutrition (B) Respiration (C) Excretion Plants excretes (A) Water vapour (B) Carbon dioxide (C) Both The process of a cow giving birth to a calf illustrates (A) Respiration (B) Excretion (C) Reproduction The given figure illustrates seed germination.

(D) Reproduction (D) None (D) Growth

The given figure represents which of the following characteristics of living things? (A) Excretion (B) Movement (C) Nutrition (D) Reproduction A seed germinating into a new plant is an example of i . Fishes taking up dissolved oxygen present in water through gills is an example of ii . The information in which alternative completes the given statements? (A) i- respiration ii- growth (B) i- growth ii- movement (C) i- movement ii- reproduction (D) i- reproduction ii-respiration Every day you see the animals, birds and insects moving from one place to another. Such a movement is called (A) Respiration (B) Excretion (C) Reproduction (D) Locomotion Most of the plants do not show (A) Respiration (B) Reproduction (C) Excretion (D) Locomotion Which of the following plants moves from one place to another? (A) Rose (B) Pea (C) Jasmine (D) Chlamydomonas Which of the following animals does not move from one place to another? (A) Sponges (B) Corals (C) Sea-anemones (D) All All living things respond to stimuli. Which of the following examples illustrates response to stimuli? (A) Sparrow laying eggs (B) Child growing into an adult (C) Earthworm breathing through its skin (D) Cockroaches moving to dark places to escape light The closing of the flowers of some plants after sunset illustrates (A) Growth (B) Reproduction (C) Respiration (D) Response to stimuli All living organisms respond to various stimuli. Which of the following examples illustrates the process of responding to stimuli by living organisms? (A) A chick hatching from the egg and growing into a hen (B) A bean seed germinating to give rise to a new plant (C) A fish breathing in dissolved oxygen from the water through gills (D) A cockroach running towards a hiding place when the light is switched on The life cycle of living things start with (A) A cell (B) A tissue (C) An organ (D) All In animals, the life cycle consists of (A) Birth (B) Growth (C) Reproduction (D) Death The life span of bacteria is about (A) 20 seconds (B) 20 minutes (C) 20 hours (D) 20 days The life span of tortoise is about (A) 100 min (B) 150 hours (C) 120 days (D) 130 years

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Life on Earth 35. 36. 36. 37. 38. 38. 39. 40.

12

The study of living things or life is called (A) Botany (B) Zoology (C) Biology (D) Science Aspergillus is (A) A fungi (B) An alga (C) A bacteria (D) A virus Which of the following belongs to plants? (A) Bacteria (B) Fungi (C) Algae (D) All Animals lack (A) Cells (B) Tissues (C) Organs (D) Chlorophyll Plants prepare their own food material due to the presence (A) Cells (B) Tissues (C) Organs (D) Chlorophyll Nutrition in plants is (A) Autotrophic (B) Heterotrophic (C) Saprophytic (D) None Nutrition in animals is (A) Autotrophic (B) Heterotrophic (C) Saprophytic (D) None Living organisms display several forms of movement. Muscle fibers, muscle joints, webbed feet, wings, fins, feathers, muscles etc. assist in several forms of movement. Which of the following statements holds true for movements? (A) Only animals move (B) Only plants move (C) Plants do not move (D) Both plants and animals move

Conceptive Worksheet 1. 2. 3. 4. 5. 6. 7.

8. 9. 10. 11. 12. 13. 14. 15.

List out the common feature of living and non living things. Living things are both unicellular and multicellular. Name some unicellular and multicellular organisms. For preparing their food, plants also require carbon dioxide. How is it absorbed from atmosphere? What are the raw materials required by the plants for photosynthesis? Differentiate autotrophic nutrition and heterotrophic nutrition. Define the following terms. (i) Response (ii) Stimulus (iii) Phototrophic (iv) Geotrophic Name the following. (i) Waste products produced in animals. (ii) Waste products produced in plants. What happens during growth in non living things and living things. Which of the following shows reproduction? (i) Cat (ii) Mango tree (iii) Rose plant (iv) Stone (v) Table How can you distinguish between the life cycle and life span of a living thing? Write the differences between living things and non living things. What are micro organisms? List some of them. How can we see the micro organisms when they are not visible to our naked eye? Write a note on locomotion of plants. Write some differences between plants and animals.

Summative Worksheet I. 1. 2. 3. 4.

Multiple choice questions. Which one is not a unicellular organism? (A) Bacteria (B) Mushroom (C) Yeast A multicellular organism has (A) Many cells (B) No cells (C) Only one cell The process of food manufacture by the green plants is called (A) Respiration (B) Growth (C) Photosynthesis Respiration is a process during which (A) Carbon dioxide is taken in (B) Oxygen is taken in (C) Both oxygen and carbon dioxide are taken in (D) None of the above

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(D) Amoeba (D) Both A & B (D) Excretion

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The process of removal of waste materials from the body is called (A) Respiration (B) Excretion (C) Photosynthesis (D) Nutrition II. Fill in the blanks 1. The branch of science dealing with the study of living beings is called _________________. 2. Basic unit of life is called _________________. 3. An organism made up of a single cell is called _________________. 4. All living things are made up of _________________. 5. All living things breathe in and breathe out _________________. 6. An animal which cannot move is _________________ 7. Removal of metabolic wastes from the body is known as _________________. 8. The green colour of plants is due to the presence of _________________. III. Complete the following table and on the basis of your observations, conclude whether the given living thing is an animal or a plant: S.No. Living Characteristics Observed Conclusion Nutrition Growth Cell wall Movement Thing (autotrophic/ (limited/ (present/ (plant/animal) (yes/no) heterotrophic) unlimited) absent) (i) Frog (ii) Grass (iii) Mushroom (iv) Earthworm (v) Housefly (vi) Algae (vii) Cow (viii) Fish IV. Write true or false in front of the statements given below: Statement True/False (i) Animal cells possess cell walls. (ii) Growth in plants is unlimited. (iii) Cells can be seen with the naked eye. V. Study the characteristics mentioned in the following table for the following objects : orange, hen's egg, curd, bag, frog, honey, milk, earthworm, sparrow. Put 'p' or 'a' for presence or absence of the characteristic and mention which of the objects are living or non-living. Conclusion S.No. Object Characteristic (Living / non-living) Respiration Excretion Nutrition Growth Reproduction (i) Orange (ii) Hen's egg (iii) Curd (iv) Bag (v) Frog (vi) Honey (vii) Milk (viii) Earthworm (ix) Sparrow VI. Answer the following questions: 1. Which of the following are living objects? Milk, honey, orange, hen's egg, curd. 2. A motor car moves, takes in oxygen and gives out carbon dioxide, consumes fuel but is not a living creature. In what ways does it not qualify as a living organism? 3. Name a plant which is not green, and one animal which does not move about freely. 4. Name one microscopic plant and one microscopic animal. 5. Why do all living organisms need food? 6. Which part of leaf takes part in exchange of gases? www.bemedicos.com ____________________________________________________________________________________________________

Life on Earth

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By the end of this chapter, you will understand  Define classification  Understand the need and advantages of. classification  Understand how biologists classify organisms  Differentiate between invertebrates and vertebrates  Know about the major groups of invertebrates and vertebrates  Know about the non-flowering and flowering plants, and their major groups  Learn about the classification of plants on the basis of habit Life cycle, mode of nutrition and habitat  Understand the need of scientific names

Classification of Living Beings Chapter -2

Learning Outcomes

1. CLASSIFICATION The planet Earth has more than 15 lakh different kinds of living organisms. These living beings show infinite diversity. No two individuals are alike. It is impossible to study them individually. So, what to do? How to simplify the study of these many living organisms. To make the study of living organisms easier, scientists put together similar things into groups or categories. They separate the categories on the basis of differences. The study of even a single member of the group provides us information about the other members of the group. This process of grouping living things on the basis of similarities and differences is called classification. Man, since times immemorial, has been classifying things present in his surroundings. He distinguished between plants and animals. He classified plants into edible and non-edible. Classification by the primitive man was need-based and useful for his survival. Classification, in a broad sense, not only involves grouping of organisms into categories, it also includes their identification and naming. ADVANTAGES OF CLASSIFICATION 1. Classification makes the study of living organisms simpler and easier. 2. It helps in easy identification of different organisms. 3. Affinities or relationships between different organisms are easily known. 4. It helps in tracing the possible origin of organisms. 2. CLASSIFICATION OF THE LIVING ORGANISMS Living organisms have been divided into two kingdoms, called the animal kingdom and the plant kingdom. These two kingdoms were further divided and subdivided into lower and lower categories. The lowest category is known as the species. For example, man is one species, dog is another, and so is others like neem, mango, coconut. Members of a species resemble one another more than they resemble members of other species. Members of a species can breed among themselves, and not with the members of another species. Each species has a specific name. 3. ANIMALS — VERTEBRATES AND INVERTEBRATES Animals are divided into two big groups — (i) invertebrates and (ii) vertebrates. INVERTEBRATES The animals which have no backbone or bony skeleton are called invertebrates. Insects are the largest group of invertebrates. Examples: Amoeba, Euglena, sea anemone, tapeworm, cockroach, earthworm, insects, snail, starfish. VERTEBRATES The animals with a backbone are called vertebrates. The backbone is made up of several small bones called vertebrae. Examples: Fishes, frog, toad, snake, lizard, birds, monkey, cow, cat, kangaroo, elephant, humans.

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Formative Worksheet 1. 2.

3. 4. 5. 6. 7. 8. 9. 10.

The process of grouping living things on the basis of similarities and differences is called (A) Nomenclature (B) Classification (C) Taxonomy (D) All Statement-I: Classification makes the study of living organisms simpler and easier. Statement-II: It helps in easy identification of different organisms. (A) Statement-I is true, Statement –II is false (B) Statement-I is false, Statement –II is true (C) Both statements are true (D) Both statements are false Living organisms are divided into (A) Plant kingdom (B) Animal kingdom (C) Both (D) None Which of the following members resemble each other? (A) Species (B) Genere (C) Class (D) None The animals which have no backbone or bony skeleton are called (A) Vertebrates (B) Invertebrates (C) Aves (D) Mammals Which of the following is an invertebrate? (A) Amoeba (B) Euglena (C) sea anemone (D) All Snail is (A) A vertebrate (B) An invertebrate (C) Both (D) None The animals which have backbone or bony skeleton are called (A) Vertebrates (B) Invertebrates (C) Aves (D) Mammals Which of the following is a vertebrate? (A) Fishes (B) Frog (C) Snake (D) All Kangaroo is (A) a vertebrate (B) an invertebrate (C) both (D) none

Conceptive Worksheet 1. 2.

3. 4. 5. 6. 7. 8. 9. 10.

Classification includes (A) Grouping (B) Identification (C) Naming (D) All Statement-I: Affinities or relationships between different organisms are easily known through classification Statement-II: Classification helps in tracing the possible origin of organisms. (A) Statement-I is true, Statement –II is false (B) Statement-I is false, Statement –II is true (C) Both statements are true (D) Both statements are false The lowest category of classification is known as (A) Species (B) Genere (C) Class (D) None Animals are divided into (A) Vertebrates (B) Invertebrates (C) Both (D) None The largest group of invertebrates is (A) Protozoa (B) Porifera (C) Insects (D) Flatworms Which of the following is an invertebrate? (A) Tapeworm (B) Cockroach (C) Earthworm (D) All Which of the following has no backbone or bone skeleton? (A) Fish (B) Frog (C) Pigeon (D) Starfish In vertebrates, the backbone is made up of several (A) Muscles (B) Arteries (C) Veins (D) vertebrae Which of the following is a vertebrate? (A) Lizard (B) Birds (C) Monkey (D) All Which of the following has backbone or bone skeleton? (A) Fish (B) Frog (C) Pigeon (D) Starfish

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4. INVERTEBRATES The invertebrates are further divided into 8 groups. These groups possess different characteristics. 1. PROTOZOA  Single-celled animals.  Small and microscopic.  Found in soil, in water and even inside the bodies of other animals including humans. Examples:

Figure 2.1 : Amoeba

Figure 2.2 : Paramecium

2. PORIFERA  Porous (pore-bearing) animals; pores present all over the body.  Mostly found in sea water, only some in fresh water.  Found attached to the bottom of the sea or pond; so do not more from place to place.  A large opening present at the top.

Figure 2.3 : Sycon

Figure 2.4 : Spongilla

3. COELENTERATA  Hollow sac-like animals.  Body bag-shaped with only opening called mouth.  Mouth surrounded by a number of finger-like structures called tentacles.

Figure 2.5 : Hydra

Fig. 2.6 : Sea anemone

4. HELMINTHS  Include flatworms and roundworms.  Body thin and flattened in flatworms and long cylindrical in roundworms.  Mostly live inside the body of other animals including humans (as parasites).

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Figure 2.7 : Tapeworm (Flatworm)

Fig. 2.8: Ascaris (Roundworm)

5. ANNELIDA  Segmented, soft body  Found in a variety of habitats- fresh water, marine water as well as land.  Earthworm and leeches are included

Figure 2.9 : Earthworm

Figure 2.10 : Leech

6. ARTHROPODA  Joint-footed animals  Tough outer covering (exoskeleton) present outside the body.

Figure 2.11 : Butterfly

Figure 2.12 : Spider

Figure 2.13 : Cockroach

7. MOLLUSCA  Body soft and unsegmented.  Body enclosed in a hard shell. 8. ECHINODERMATA  Body rough and spiny.  Body star-shaped or ball-like.  Occur in sea (marine animals).

Fig. 2.14 : Snail (Mollusca)

Fig. 2.15 : Starfish (Echinodermata)

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Table 2.1 Animals without Vertebral Column (without backbone) : Invertebrates Major Groups Examples 1. PROTOZOA (One-celled animals) Amoeba, Paramecium, Euglena 2. PORIFERA (Porous animals) Sponges 3. COELENTERATA (Hollow sac animals) Hydra, Sea anemone 4. HELMINTHS (Flatworms and roundworms) Flatworm (liver fluke, tapeworm), Roundworm (Ascaris) 5. ANNELIDA (Segmented worms) Earthworm 6. ARTHROPODA (Joint-footed animals) Butterfly, Honeybee, Cockroach, Spider, Scorpion, Prawn, Crab 7. MOLLUSCA (Soft-bodied animals) Snail, Mussel, Octopus 8. ECHINODERMATA (Spiny-skinned animals) Starfish, Brittle star, Sea urchin 5. VERTEBRATES Vertebrates, the animals with a backbone, can be divided into five groups. Each group possesses distinct characters. Where is backbone present in your body? The long, hard bone starting from below the neck till the end of your back is the backbone. The backbone is made up of small bones called vertebrae. You can feel its presence by running over your back in its centre with your hand. The hard structure which you feel is the backbone. 1. PISCES  Live in water.  Body streamlined which helps in swimming.  Breathe through special organs called gills. Figure 2.16 : Fish 2. AMPHIBIA  Can live in water as well as on land.  Lay eggs in water.  Breathe through lungs and moist skin. Figure 2.17 : Frog 3. REPTILES  Mostly found on land.  Body covered with scales.  Breathe through lungs.

Figure 2.18 : Tortoise

Figure 2.19 : Crocodile

4. AVES (BIRDS)  Body covered with feathers.  Wings present; help in flying.  Streamlined body; helps in flying.  Bones are hollow; helps to keep the body light. Fig. 2.20 : Pigeon www.bemedicos.com ____________________________________________________________________________________________________

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5. MAMMALS  Body covered with hair.  Give birth to young ones.  Mammary glands present; nourish their young ones with their own milk.  Breathe through lungs.

Figure 2.21: Bat

Figure 2.22: Rabbit

Figure 2.23: Kangaroo

Table 2.2: Animals with Vertebral Columns (with backbone) : Vertebrates Major Groups Examples 1. PISCES (Fishes) Rohu, shark, sardine. 2. AMPHIBIA Toads and frogs. 3. REPTILES Snakes, lizards, crocodiles and tortoise. 4. AVES (Birds) Peacock, sparrow, crow. 5. MAMMALS Elephant, rhinoceros, lion, monkey, porcupine, cat, cow, dog, kangaroo, bat, whale, dolphin, and man. 6. OTHER CRITERIA FOR GROUPING ANIMALS 1. There is another way to group the animals. Animals like the frogs, in which the body temperature changes with changes in the temperature of the environment are called coldblooded. Animals in which the body temperature remains constant and does not change with change in temperature of the environment are called warm-blooded. Birds and mammals are the only animals that are warm-blooded. Man, cats, mice, bats, tigers and elephants are all warm-blooded. 2. Animals can also be classified on the basis of their body covering or coats like scales (as in snakes, fishes), feathers (as in birds), slimy skin (as in frog), hair or fur (as in mammals). 3. Another way to classify animals can be on the basis of reproduction. Some animals reproduce by laying eggs (such as frogs, birds) while some others give birth to young ones (as in mammals). 4. On the basis of nutrition : Animals are heterotrophic in nutrition, as they derive their food from other organisms, being unable to prepare their own food. Heterotrophic animals may be of two types — (i) Holozoic or (ii) Parasitic. Holozoic animals consume the whole food (animal or plant or their parts) into their body and then digest it. Such a nutrition is called holozoic. Holozoic animals may be herbivores (those eating plants; like horse, cow, elephant), carnivores (those eating other animals; like cats, dogs, lions) or omnivores (those who eat both plants and animals; like man). Parasitic animals live on other organisms (called the host organism) and derive nutrition from the host. The organism deriving nutrition from the host is called the parasite. Examples: 1. Malarial parasite which causes malaria lives inside the body of man (the host). 2. Tapeworm is a parasite with man as the host. 3. Entamoeba, the parasite, lives inside the human body (the host) and causes dysentery.

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6th Biology

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Formative Worksheet 11. 12. 13.

14. 15. 16. 17. 18.

19. 20.

21. 22. 23. 24.

25. 26.

27.

Single celled organisms belong to (A) Protozoa (B) Porifera (C) Coelenterata (D) Helminths Which of the following is a protozoan? (A) Sponge (B) Hydra (C) Paramecium (D) Star fish Which of the following is not a protozoan? (A) Sea anemone (B) Ascaris (C) Earthworm (D) Brittle fish Sycon belongs (A) Protozoa (B) Porifera (C) Coelenterata (D) Helminths Which of the following is not a poriferan? (A) Sycon (B) Spongilla (C) Both (D) None Hollow sac animals belong to (A) Protozoa (B) Porifera (C) Coelenterata (D) Helminths Which of the following belongs to coelenterata? (A) Sponge (B) Hydra (C) Paramecium (D) Star fish Statement - I: Round worms are included in Helminths. Statement – II: Flat worms are included in Helminths (A) Statement - I is true, Statement - II is false.(B) Statement - I is false, Statement - II is true. (C) Both statements are true. (D) Both statements are false. Tapeworm belong to (A) Protozoa (B) Porifera (C) Coelenterata (D) Helminths Statement - I: Animals with segmented bodies are included in Helminths. Statement – II: Earthworm belongs to annelida. (A) Statement - I is true, Statement - II is false (B) Statement - I is false, Statement - II is true (C) Both statements are true (D) Both statements are false Which of the following does not belong to annelida? (A) Earthworm (B) Leech (C) Snail (D) Spider Exoskeleton in present in the animals of (A) Protozoa (B) Porifera (C) Arthropoda (D) Annelida Which of the following belongs to arthropoda? (A) Butterfly (B) Cockroach (C) Spider (D) None Snail belongs to (A) Echinodermata (B) Helminths (C) Annelida (D) Mollusca Spiny skinned animals are placed in (A) Arthropoda (B) Helminths (C) Annelida (D) Echinodermata Match the following Column – I Column- II (k) Protozoa (p) Ascaris (l) Porifera (q) Hydra (m) Coelenterata (r) Sycon (n) Helminths (s) Euglena (A) klmn/pqrs (B) klmn/qprs (C) klmn/srqp (D) klmn/spqr Match the following Column – I Column- II (k) Annelida (p) Sea urchin (l) Arthropoda (q) Octopus (m) Mollusca (r) Scorpion (n) Echinodermat a (s) Leech (A) klmn/pqrs (B) klmn/qprs (C) klmn/srqp (D) klmn/spqr

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Classification of living beings 28.

29.

30.

31. 32. 33. 34. 35. 36.

Match the following Column – I (body) Column- II (group) (k) Spiny skin (p) Annelida (l) Soft and segmented (q) Echinodermata (m) Porus (r) Porifera (n) Hollow sac (s) Coelenterata (A) klmn/pqrs (B) klmn/qprs (C) klmn/srqp (D) klmn/spqr Match the following Column – I (body) Column- II (group) (k) One celled (p) Mollusca (l) Soft and unsegmented (q) Heliminths (m) Flat, long & cylindrical (r) Arthropoda (n) Joint legs (s) Protozoa (A) klmn/pqrs (B) klmn/qprs (C) klmn/srqp Statement-I: The body of Pisces is streamlined that helps in swimming. Statement-II: Fishes breathe through gills. (A) Statement-I is true, Statement –II is false (B) Statement-I is false, Statement –II is true (C) Both statements are true (D) Both statements are false Which of the following is an amphibian? (A) Fish (B) Frog (C) Crocodile Which of the following is a reptilian? (A) Tortoise (B) Crocodile (C) Both Which of the following group of animals are covered with feathers? (A) Pisces (B) Amphibians (C) Reptiles Bat belongs to (A) Amphibians (B) Reptiles (D) Mammals Which of the following animals lay eggs? (A) Amphibians (B) Reptiles (C) Aves Match the following. Column – I Column- II (k) Amphibian (p) Rabbit (l) Reptilian (q) Pigeon (m) Avian (r) Crocodile (n) Mammalian (s) Frog (A) klmn/pqrs (B) klmn/qprs (C) klmn/srqp

22

(D) klmn/spqr

(D) Pigeon (D) None (D) Aves (D) Aves (D) All

(D) klmn/spqr

Conceptive Worksheet 11. 12. 13. 14. 15. 16. 17. 18.

Amoeba belongs (A) Protozoa (B) Porifera (C) Coelenterata (D) Helminths Which of the following is not a protozoan? (A) Euglena (B) Amoeba (C) Paramecium (D) Star fish Porus animals belong to (A) Protozoa (B) Porifera (C) Coelenterata (D) Helminths Which of the following is a poriferan? (A) Sponge (B) Hydra (C) Paramecium (D) Star fish Which of the following is not a poriferan? (A) Hydra (B) Flatworm (C) Leech (D) Cockroach Hydra belongs (A) Protozoa (B) Porifera (C) Coelenterata (D) Helminths Which of the following does not belong to coelenterata? (A) Amoeba (B) Sycon (C) Ascaris (D) None Which of the following mostly live inside the body of other animals including humans? (A) Sea anemone (B) Ascaris (C) Earthworm (D) Brittle fish

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20. 21. 22. 23. 24. 25. 26. 27.

28. 29. 30. 31. 32. 33.

Arthropoda includes (A) Soft and segmented animals (B) Soft and unsegmented animals (C) Porus animals (D) Joint footed animals Butterfly belongs to (A) Protozoa (B) Porifera (C) Arthropoda (D) Annelida Animals with soft and unsegmented bodies are included in (A) Protozoa (B) Porifera (C) Annelida (D) Mollusca Starfish belongs to (A) Echinodermata (B) Helminths (C) Annelida (D) Mollusca Body is star shaped or ball shaped in the animals of (A) Porifera (B) Echinodermata (C) Annelida (D) Helminths Brittle fish belongs (A) Echinodermata (B) Helminths (C) Annelida (D) Mollusca Fish belongs to (A) Pisces (B) Amphibians (C) Reptiles (D) Aves The animals that can live both in water and on land are included in (A) Pisces (B) Amphibians (C) Reptiles (D) Aves Which of the following is true for amphibians? (A) Can live in water as well as on land (B) Lay eggs in water (C) Breathe through lungs and moist skin (D) All the above Pigeon belongs to (A) Pisces (B) Amphibians (C) Reptiles (D) Aves Which of the following group of animals have hollow bones? (A) Pisces (B) Amphibians (C) Reptiles (D) Aves Which of the following animals give birth to young ones? (A) Amphibians (B) Reptiles (C) Mammals (D) Aves Frog respires with the help of (A) Lungs (B) Moist skin (C) Gills (D) Both (A) & (B) Mammals respire with the help of (A) Lungs (B) Moist skin (C) Gills (D) Both (A) & (B) Kangaroo belongs to (A) Amphibians (B) Reptiles (C) Mammals (D) Aves

7. PLANT KINGDOM There are many different kinds of plants in the world. They show a great diversity from single-celled microscopic ones to huge trees. Broadly, plants can be divided into two main groups - (i) the flowering plants, and (ii) the non-flowering plants. Flowering plants, as the name suggests, bear flowers and fruits. Mango, neem, peepal, lotus, rose, sunflower, grass, cycas and pine are flowering plants. Non-flowering plants do not bear flowers. They include the bacteria, algae, mushrooms, mosses and ferns. 8. NON-FLOWERING PLANTS 1. BACTERIA     

Unicellular. Microscopic. Occur everywhere - in air, water, soil and the food we eat. In shape, bacteria may be spherical, rod-shaped or spiral. Some bacteria can make their own food, whereas others cannot.

Figure. 2.24 : Bacteria

2. ALGAE  Found in water (aquatic).  Contain chlorophyll and can prepare their own food. www.bemedicos.com ____________________________________________________________________________________________________

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 May be unicellular (Chlamydomonas) or filamentous (Spirogyra).

Figure 2.25 : Chlamydomonas

Figure 2.26 : Spirogyra

3. Fungi (Fig. 2.27)  Non-green plants (lack chlorophyll).  Cannot prepare their food; live on dead 4. Bryophyta (Fig. 2.28)  Green plants.  Found in moist, shady places. 5. Pteridophyta (Fig. 2.29)  Green plants.  Found in moist, shady places.

Figure. 2.27 : Mushroom

decaying matter (saprophytic).

Figure 2.28 : Moss

Figure. 2.29 : Fern

9. FLOWERING PLANTS/SEED-BEARING PLANTS These may be: (i) Gymnosperms, the plants bearing seeds but no fruits as in cycas, pinus (Figure 2.30), and (ii) Angiosperms, the plants bearing seeds which are enclosed inside fruits, as in mango, guava, brinjal, tomato, maize, wheat, sugarcane. Angiosperms are further divided into two groups depending on the number of seed leaves (cotyledons) Figure 2.30 : Cycas present in the seeds.  Dicotyledonous plants, in which seeds contain two seed leaves, as in gram, pea, bean, brinjal, mango.  Monocotyledonous plants, in which seeds contain only one seed leaf, as in wheat, maize, rice.

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Table 2.3: Major groups of flowering and non-flowering plants Major Groups Examples Non-flowering plants 1. BACTERIA Escherichia coli, Diplococcus pneumoniae. 2. ALGAE Chlamydomonas, Spirogyra, Volvox, seaweed. 3. FUNGI Yeast, Mucor, Rhizopus (bread mould), mushroom. 4. BRYOPHYTA Liverworts and mosses. 5. PTERIDOPHYTA Ferns, horse-tails. Flowering Plants 6. GYMNOSPERMS Pinus (pine), Cycas (cycad). 7. ANGIOSPERMS Lotus, water lily, water hyacinth, neem banyan, mango, sunflower. 10. CLASSIFICATION ON THE BASIS OF HABIT Flowering plants are further classified on the basis of their habit as trees, shrubs and herbs. Herbs are small plants with a soft stem. They do not grow more than three to four feet in height [Figure 2.31]. Examples: Mustard, sunflower, petunia, pea, wheat, paddy and balsam. Shrubs are medium-sized plants with hard and woody stems. Many branches are seen rising just above the ground [Figure 2.32]. Examples: China-rose, oleander, rose, lemon, lantana, pomegranate and henna. Trees are tall plants with hard and woody stems. They have a main trunk from which branches and leaves arise [Figure. 2.33]. Trees generally survive for a number of years. Examples: Mango, coconut, neem, peepal.

Figure 2.31: Herb

Figure 2.32: Shrub

Figure 2.33: Tree

11. CLASSIFICATION ON THE BASIS OF LIFE CYCLE On the basis of the life cycle, flowering plants can be classified as annuals, biennials, and perennials (Figure 2.34). Plants which complete their life cycle in one year from seed to flower, fruit and seed and then die, are called annuals. Examples: Most herbs. Biennials are those plants which complete their life cycle in two years. In the first year, these plants just grow, and produce flowers, fruits and seeds in second year. Examples: Radish, carrot, beet-root, turnip. Perennials are plants living for many years. Every year they produce flowers, fruits and seeds. Examples: Mango, neem, peepal, jamun, guava and palms. Annual plants have a one-year life cycle. They grow from seed into flower, produce new seeds and die in the same year.

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Classification of living beings

Figure 2.34

26 Biennial plants have a two-year life cycle. In the first year, they grow leaves and roots. In the winter, the leaves die. The roots survive and new leaves, flowers and seeds are produced in the second year. The plant then dies. Perennial plants live for many years and produce roots that store food. Food is also sometimes stored in other organs. The roots survive the winter and the plant produces leaves, flowers and seeds year after year.

12. CLASSIFICATION ON THE BASIS OF MODE OF NUTRITION IN PLANTS Like animals, plants need food. Based on their nutrition, the plants are classified into two categories 1. autotrophic, and 2. heterotrophic. 1. Autotrophic plants, or autotrophs, as discussed earlier, are those plants which synthesize their own food. These plants are green-coloured as the green pigment, chlorophyll, is present. 2. Heterotrophic plants, or heterotrophs, are non-green plants, and are dependent on other plants or animals for obtaining food. Heterotrophs can be grouped into two types, depending upon the source from which they derive their nutrition, as parasites and saprophytes. Heterotrophs which feed on the dead and decomposed bodies of plants and animals are called saprophytes. Examples include yeast, mushrooms and some other fungi. Heterotrophs which obtain their food from other living organisms (without killing them) are called parasites. Cuscuta (dodder plant, also called amarbel), Viscum (mistletoe), and Orobanche (broomrape) are examples of parasites. 13. CLASSIFICATION ON THE BASIS OF HABITAT Plants on the basis of their natural place of occurrence (habitat) are classified as 1. mesophytes, 2. hydrophytes, and 3. xerophytes. 1. Mesophytes are plants living on land with sufficient water, like most herbs and trees. 2. Hydrophytes live in water like lotus, water lily, hyacinth, algae. 3. Xerophytes are plants living on land having scarcity of water, as in a desert. Plants like cacti, babool and ber are xerophytes (Figure 2.35). Figure 2.35 : Cactus 14. SCIENTIFIC NAMES The common name of a species often varies with the language and region of the world. For instance, onion in English is called ‘piyaz’ in Hindi and Bengali, ‘irulli’ in Kannada, and 'vengayarri in Tamil. Similarly, banana in English is called 'keh' in Hindi, Punjabi and Gujarati, 'kald in Bengali and 'kadali' in Marathi. The local names of one country or one region of a country may not be understood by people in other countries or other regions of the same country. Thus, the need to have an internationally accepted name for the species was felt. The modern system of naming living organisms or species is a binomial system. It was introduced by the Swedish botanist, Carolus Linnaeus. ____________________________________________________________________________________________________

C. Linnaeus

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6th Biology

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Binomial system means that the name of each organism consists of two words — a generic name and a specific name. As mentioned earlier, the lowest category of classification is called the species. The individuals of a species possess maximum common features and can reproduce freely in nature. Many different species having some common features are grouped in a bigger and higher rank called the genus. The scientific names of some common organisms or species are given below: 1. Frog –– Rana tigrina 2. Man –– Homo sapiens 3. Housefly –– Musca domestica 4. Peacock –– Pavo cristatus 5. Indian tiger –– Panthera tigris 6. Mango –– Mangifera indica 7. Banana –– Musa sapicntum 8. Onion –– Allium cepa 9. Rose –– Rosa ccntifolia 10. China rose –– Hibiscus rosa-sinensis The first letter of the first word, which is the generic name, is always written with a capital letter, while the first letter of the second word, which is the specific name, is written with a small letter. Thus, in the scientific name of frog, Rana tigrina, Rana is the genus and tigrina represents the species. Binomial system means that the name of each organism, in fact, consist of two names the first name refers to the genus and the second name is called the species name. SNAP SHOT 1. There are more than 15 lakh different kinds of living organisms on the planet Earth. 2. Living things, because of the enormous diversity, are grouped into categories, so as to make their study easier. This process is termed classification. 3. Species is the lowest category in classification. A species is a group of similar organisms which resemble one another more than they resemble members of other species. Also, members of a species reproduce among themselves, and not with members of another species. 4. Naming of species follows binomial system, which was proposed by Linnaeus. Thus, the name of each organism has two parts — a generic name and a specific name. 5. Animals are broadly classified as vertebrates (with backbone) and invertebrates (without backbone). 6. Plants are broadly classified as flowering and non-flowering plants. 7. Based on life cycle, flowering plants may be annuals, biennials or perennials. 8. Based on habit, plants are classified as herbs, shrubs or trees; on the basis of nutrition, plants may be autotrophic or heterotrophic (parasites or saprophytes); based on habitat, plants may be xerophytes, mesophytes or hydrophytes.

Formative Worksheet 37.

38. 39.

Statement-I: Alga is a flowering plant. Statement-II: Mango is a non flowering plant. (A) Statement-I is true, Statement –II is false (B) Statement-I is false, Statement –II is true (C) Both statements are true (D) Both statements are false The shape of bacteria is (A) Spherical (B) Rod-shaped (C) Spiral (D) All Statement-I: Some bacteria can prepare its own food material. Statement-II: Some bacteria can prepare its own food material. (A) Statement-I is true, Statement –II is false (B) Statement-I is false, Statement –II is true (C) Both statements are true (D) Both statements are false

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Classification of living beings 40.

41. 42. 43. 44.

45.

46. 47. 48.

49.

50.

51. 52. 53. 54.

55.

28

Statement-I: Bacteria are multicellular. Statement-II: Algae are unicellular. (A) Statement-I is true, Statement –II is false (B) Statement-I is false, Statement –II is true (C) Both statements are true (D) Both statements are false Which of the following is an alga? (A) Chlamydomonas(B) Moss (C) Fern (D) Mushroom Which of the following plant group is found in moist and shady places? (A) Bacteria (B) Algae (C) Pteridophyta (D) Fungi Which of the following belongs to Bryophyta? (A) Spirogyra (B) Mushroom (C) Moss (D) Fern Which of the following is true for fern? (A) It belongs to Pteridophyta (B) It is found in moist and shady places. (C) It is green in colours (D) All the above Statement-I: Gymnosperms, the plants bearing seeds but no fruits. Statement-II: Angiosperms, the plants bearing seeds which are enclosed inside fruits (A) Statement-I is true, Statement –II is false(B) Statement-I is false, Statement –II is true (C) Both statements are true (D) Both statements are false Which of the following is a gymnosperm? (A) Mango (B) Guava (C) Cycas (D) Brinjal Which of following is not a dicotyledonous plant? (A) Maize (B) Wheat (C) Rice (D) All Match the following Column – I Column- II (k) Bacteria (p) moss (l) Algae (q) Mucor (m) Fungi (r) Volvox (n) Bryophyta (s) Escherichia coli (A) klmn/pqrs (B) klmn/qprs (C) klmn/srqp (D) klmn/spqr Match the following Column – I Column- II (k) Bacteria (p) Diplococcus pneumoniae. (l) Algae (q) Spirogyra (m) Fungi (r) Rhizopus (n) Bryophyta (s) Liverwort (A) klmn/pqrs (B) klmn/qprs (C) klmn/srqp (D) klmn/spqr Match the following Column – I Column- II (k) Bryophyta (p) horse-tails (l) Pteridophyta (q) Pinus (m) Gymnosperm (r) water hyacinth (n) Angiosperms (s) moss (A) klmn/pqrs (B) klmn/qprs (C) klmn/srqp (D) klmn/spqr Which of the following is a shrub? (A) Rose (B) Lemon (C) Lantana (D) All Which of the following has hard and woody stem? (A) Petunia (B) Pomegranate (C) Henna (D) Peepal Radish is (A) an annual (B) a biennial (C) a perennial (D) All Match the following Column – I Column- II (k) Annual (p) wheat (l) Biennial (q) turnip (m) Perennial (r) palm (A) klm/pqr (B) klm/qpr (C) klm/rqp (D) klm/pqr Which of the following is a saprophyte? (A) Cuscuta (B) Yeast (C) Mushroom (D) Viscum

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6th Biology

29 56.

57.

58.

Match the following Column – I (k) Mesophyte (l) Hydrophyte (m) Xerophytes (A) klm/pqr (B) klm/qrp Match the following Column – I (Animal/Plant) (k) Frog (l) Housefly (m) Banana (n) Onion (A) klmn/pqrs (B) klmn/qpsr Match the following Column – I (Animal/Plant) (k) Man (l) Indian tiger (m) Mango (n) China rose (A) klmn/pqrs (B) klmn/qpsr

Column- II (p) babool (q) Mango (r) algae (C) klm/rqp

(D) klm/pqr

Column- II (Scientific name) (p) Musca domestica (q) Rana tigrina (r) Allium cepa (s) Musa sapicntum (C) klmn/srqp

(D) klmn/spqr

Column- II (Scientific name) (p) Hibiscus rosa-sinensis (q) Mangifera indica (r) Panthera tigris (s) Homo sapiens (C) klmn/srqp

(D) klmn/spqr

Conceptive Worksheet 34.

35. 36.

37. 38.

39.

40. 41. 42.

43. 44. 45.

46.

Bacteria is a (A) Flowering plant (B) Non flowering plant (C) Both (D) None Algae can prepare its own food material due to the presence of (A) Chlorophyll (B) Xanthophylls (C) Both (D) None Filamentous alga is (A) Chlamydomonas (B) Spirogyra (C) Both (D) None Mushroom belongs to (A) Fungi (B) Algae (C) Pteridophyta (D) Bryophyta Which of the following are flowering plants? (A) Gymnosperms (B) Angiosperms (C) Both (D) None Statement-I: In dicotyledonous plants, seeds contain two seed leaves. Statement-II: In monocotyledonous plants, seeds contain only one seed leaf. (A) Statement-I is true, Statement –II is false(B) Statement-I is false, Statement –II is true (C) Both statements are true (D) Both statements are false Which of the following is a dicotyledonous plant? (A) Maize (B) Wheat (C) Rice (D) Pea Which of the following is a herb? (A) Mustard (B) China-rose (C) Oleander (D) neem Plants which complete their life cycle in one year from seed to flower, fruit and seed and then die, are called (A) Perennials (B) Monocots (C) Monophytes (D) Annuals Which of the following is a biennial? (A) carrot (B) sunflower (C) Neem (D) Mango Which of the following show autotrophic nutrition? (A) Green plants (B) Yeast (C) Mushroom (D) Viscum Which of the following is a true about Cuscuta? (A) It is a heterotroph (B) It is a parasite (C) It is an autotroph (D) All The modern system of naming living organisms or species is a binomial system. It was introduced by (A) Aristotle (B) Darwin (C) Lamarck (D) Carolus Linnaeus

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Classification of living beings

30

Summative Worksheet I. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14.

II. 1. 2. 3. 4. 5. 6 7. 8. 9. 10. III. 1. 2. 3. 4. 5. 6. 7. 8.

Multiple choice questions. Lowest category of classification is (A) Genus (B) Species (C) Kingdom Animals without vertebral column are called (A) Vertebrates (B) Mammals (C) Invertebrates Earthworm belongs to (A) Porifera (B) Arthropoda (C) Annelida Pore-bearing animals belong to (A) Protozoa (B) Porifera (C) Coelenterata Tentacles are present in (A) Hydra (B) Paramecium (C) Snail Respiration through gills occurs in (A) Pisces (B) Amphibia (C) Mammals Animals which can live both in water and on land belong to (A) Mollusca (B) Amphibia (C) Aves Which of the following is a heterotrophic organism? (A) Mushroom (B) Spirogyra (C) Fern An example of a non-flowering plant is (A) Fern (B) Pinus (C) Mango Aquatic non-flowering plants are (A) Algae (B) Fungi (C) Bryophytes Seed-bearing plants lacking fruits belong to (A) Dicotyledons (B) Monocotyledons (C) Angiosperms Which of the following is a perennial plant? (A) Mango tree (B) China-rose (C) Pea plant Maize is a/an (A) Gymnosperm (B) Angiosperm (C) Fern Bryophytes are found in (A) Moist, shady places (B) Any open space (C) Rocky areas (D) Water

(D) None of the above (D) Fungi (D) Mollusca (D) Annelida (D) Tapeworm (D) Reptiles (D) Mammals (D) Sunflower (D) Lotus (D) Pteridophytes (D) Gymnosperms (D) Rose (D) Bryophyte

Fill in the blanks: _________________________

is a unicellular plant. is a unicellular animal. Binomial system of naming living organisms was given by _________________________. A cold-blooded animal is _________________________. A warm-blooded animal is _________________________. Invertebrates with jointed legs belong to group _________________________. Vertebrates which can live both on land and in water are called _________________________. Two spiny-skinned animals are _________________________ and _________________________ The non-flowering plants which are green and live in water are called _________________________. _________________________ are non-flowering plants which are non-green. _________________________

Find the odd-one out. Give reasons. Amoeba, Euglena, Paramecium, Chlamydomonas. Bacteria, Chlamydomonas, Spirogyra, Volvox. Yeast, mushroom, bread mould, Chlamydomonas. Cycas, mango, neem, sunflower. Tapeworm, roundworm, liver fluke, earthworm. Starfish, brittle star, sea urchin, crab. Monkey, cow, humans, crocodile. Crocodile, tortoise, frog, snake.

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6th Biology

31

IV. (i) (ii) (iii) (iv) (v) (vi) (vii)

Which of the following statements are true (T) and which ones are false (F)? Mark T or F. Mushroom is a fungus. [ ] Fern is a flowering plant. [ ] Snail is an invertebrate animal. [ ] Bat is a vertebrate animal. [ ] Pinus is a non-flowering plant. [ ] Invertebrates have soft bodies. [ ] Dicotyledonous plants have seeds with one cotyledon. [ ]

V. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

Give the differences between: Invertebrate and Vertebrate animals Warm blooded and Cold blooded animals Flowering and Non-flowering plants Algae and Fungi Annuals and Biennials Gymnosperms and Angiosperms Herbs and Shrubs Parasites and Saprophytes Xerophytes and Hydrophytes Shrubs and Trees

VI. 1. 2. 3. 4. 5. 6.

Answer the following questions: Why do we need to classify living things? Why are scientific names of living things considered better than their common names? Write the scientific names of five commonly available plants and animals. Give two examples of parasitic animals. Name two herbivores and two carnivores. Classify the following animals into their respective groups: Snail, amoeba, hydra, earthworm, starfish, sea anemone, cockroach, roundworm, spider, sponge, butterfly, bat, whale, crocodile, frog, crow, cow, shark, prawn, butterfly. 7. Classify the following plants into herbs, shrubs and trees: Neem, mango, china-rose, rose, jasmine, oleander, mustard, sunflower, palm, tulsi and henna. 8. Classify the following plants into annuals, biennials and perennials: Grass, neem, pea, radish, paddy, rose, guava, balsam. 9. Classify the following plants into their respective groups: Fern, cycas, neem, yeast, mushroom, moss, Spirogyra, sunflower, mango, maize, water lily, lotus. 10. Classify the animals on the basis of their body covering or coat, giving examples.

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Classification of living beings

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32

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Learning Outcomes

Soil



Explain the processes by which soil is formed



Describe the layers that make up the soil



Describe the composition and properties of soil



Describe the different types of soils found in India



Explain how soil erosion takes place and how it can be prevented

1.

INTRODUCTION

Chapter -3

By the end of this chapter, you will understand  Describe the importance of soil

In India, our diet is mainly made up of cereals and vegetables, and these are obtained from plants. Wheat primarily comes from Punjab, Uttar Pradesh, and Haryana. The major rice-producing states are Punjab, Andhra Pradesh, and Uttar Pradesh. But why does so much of the rice and wheat come from these states? Why don’t other areas also grow as much? The answers to all these questions are hidden in just one word: soil. 2.

SOIL

Soil is the uppermost layer of the Earth’s crust and is usually composed of a thin layer of mineral particles, and a layer of dead and decayed plant and animal remains called humus. However, soil does not have the same properties everywhere, and therefore different varieties of plants grow in different areas. That is why we have some states growing more of a particular crop than others. There are a variety of insects, reptiles, and many other animals right under our feet! Soil also provides the vital nutrients required for plants to grow and thrive. Thus, all living organisms depend directly or indirectly on soil. 3.

SOIL FORMATION

Soil formation is a slow, stepwise process and it takes thousands of years to form a layer of soil just a few centimetres thick. It is a result of continuous breaking down of rocks by a process called weathering. Weathering is the disintegration of rocks on the Earth’s surface caused by exposure to natural forces such as wind, water, frost, roots of plants, etc. Weathering is of two types: physical and chemical weathering. Physical Weathering: In this process, rocks are broken down into smaller pieces. It is a mechanical process and does not involve any change in the characteristics of the original rock. It may be caused by temperature differences, frost, growing roots of plants, movement of animals, etc. Chemical Weathering: It is a process in which existing minerals are broken down into new mineral components. In this process, the chemical nature of the rock gets changed. Water is one of the main agents of chemical weathering. STAGES OF WEATHERING The process of weathering can be divided into three stages: Stage I: Huge pieces of parent rock begin to break up near the surface due to weathering, which can be physical or chemical.

Soil

34

Stage II: Smaller rocks continue to undergo weathering making the upper layer full of very fine rock particles. Bacteria and other micro-organisms break down plant or animal remains to form humus. This makes the soil very fertile, rich in organic material, and in several minerals vital to plant growth. Stage III: Minerals and salts seep into the ground along with water to complete the formation of soil and make it favorable for plant growth. 4.

FACTORS AFFECTING SOIL FORMATION

There are a number of factors which affect soil formation, namely, (1) Climate, (2) Characteristics of the parent rock, and (3) Slope of land. 1.

Climate: Climatic factors or Weathering forces such as temperature, rain, wind, etc., play an important role in loosening and breaking up rocks (physical weathering). Water in rock crevices expands when it freezes, causing the rocks to crack. Rocks are also worn down by wind. Soil formation is fastest in hot, moist climates and slowest in cold, dry climates. In the warm and wet tropics, bacterial activity is high, thoroughly decomposing dead plant and animal matter. As desert regions have very little vegetation and animal life, limited decaying material is available for the soil. The lack of rainfall leads to the formation of coarse-textured soil in arid regions. In areas having severe winters, bacterial activity is very slow causing dead plant and animal matter to build up. Thus, the rate of soil formation and the type of soil formed depends on the climate of a place.

2.

Characteristics of the parent rock: The composition of the parent rock also determines the kind of soil formed. For example, if the parent rock is rich in calcium, the soil formed by its weathering would also be rich in calcium

3.

Slope of land: The physical features of a place also play an important role in the formation of soil. Hilly areas generally have a thin layer of soil, because running water and wind tend to take away the soil down the slope. On flat plains, soil remains relatively undisturbed leading to the formation of a thick layer.

5.

SOIL PROFILE

Due to the physical, chemical, and biological activities that take place during soil formation, well-developed layers of soil are formed, one below the other. Typically, four distinct soil layers can be seen, distinguishable due to differences in colour and size of the particles. These layers are referred to as horizons A vertical section that shows the distinct layers of soil or horizons when we cut straight down into the soil is known as a soil profile. A Horizon or Topsoil is the uppermost layer of soil. It consists of fine particles. It is rich in humus and therefore dark in colour. It is soft, porous, and can hold water. O layer which lies just above the topsoil is rich in organic matter. B Horizon or Subsoil is rich in minerals and other materials, which seep down along with water. It also contains compactly packed fine particles of soil. C Horizon contains partly weathered pieces of rock. It is usually characterized by cracks and crevices. It is very difficult to dig beyond this layer. R Horizon or Bedrock is the lowermost layer and mainly consists of the parent rock. It undergoes weathering and starts forming the soil. The properties of this rock greatly determine the composition of the soil.

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6th Biology

35 6.

SOIL COMPOSITION

The main constituents of soil are sand, clay, silt, pebbles, and humus Table 8.1 gives the particle size of some of these constituents. The difference in the proportion of these constituents leads to the formation of different kinds of soils.

Particle

7.

Diameter (in mm)

Clay

Less than 0.002

Silt

0.002 – 0.05

Sand

0.05 – 2.00

Fine pebbles

2.00 – 5.00

Medium pebbles

5.00 – 20.00

Coarse pebbles

20.00 – 75.00

PROPERTIES OF SOIL

Soil has special properties which determine different soil types. These properties are (a) Absorption of water in soil, (b) Moisture in the soil, and (c) Percolation rate of water in soil. ABSORPTION OF WATER IN SOIL The plants that grow on land grow in the soil, and they require water in the soil to help them grow. If the soil can ‘hold’ water, the plants will grow well. If the soil does not hold water, the plants would need frequent watering or they would die. The amount of water a particular type of soil can absorb is its water absorption tendency. Higher the absorption of water by soil, higher is its availability to plants. MOISTURE IN THE SOIL When you take a little bit of soil and heat it in a test tube, you will see tiny droplets of water condensing near the mouth of the test tube. Where did this water come from? Soil has some amount of water present inside it as moisture. We can estimate the moisture content of the soil by the look and feel of it. Soil moisture helps to determine when it needs to be irrigated and how much water it needs. PERCOLATION RATE OF WATER IN SOIL The rate at which water exits the soil is known as its percolation rate. Different soils have different percolation rate of water. For proper plant growth, it is important to check percolation rate of water in soil. In a well-drained soil, water will pass rapidly after it is irrigated. On the other hand, soil with a poor percolation will hold too much water for too long a time, which can be harmful to plants. WHAT HAPPENS TO WATER WHEN IT FALLS ON CEMENTED GROUND? Cemented ground is porous to some extent. But the porosity of a cemented floor is very low as compared to soil and, therefore, water absorption is very slow. Most of the water that falls on a cemented floor evaporates or runs off, and only a very small amount seeps through it. Cemented ceilings have to be specially treated to make them waterproof, otherwise water logging would result in seepage.

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Soil 8. 

36 TYPES OF SOIL Sandy soil More than two thirds of sandy soil is sand, and about one-tenth is clay



Clayey soil More than two-thirds of clayey soil is clay.



It is made up of large particles with large air spaces



It is made up of fine particles with small air spaces



The porosity of the soil prevents retention of water.



This soil retains moisture and becomes very sticky when wet



It is well suited for fruit and vegetable cultivation



Dry clayey soil becomes hard and forms deep cracks. To improve this soil, chalk can be added

9.

SOIL SUITABILITY FOR CROPS



Loamy soil Loamy soil has sand and silt in equal amount, about two-fifth each. One-fifth of loamy soil is clay.



It has high humus content



It is porous and also holds moisture



It is good for cultivation of crops and gardening

A soil suitable for growing crops has to be fertile. What does it mean for a soil to be fertile? Soil fertility refers to the capacity of the soil to provide nutrients in adequate amounts and in proper balance for the growth of plants. For a soil to be fertile, other growth factors such as light, moisture, and temperature should be favourable. To make a soil more fertile, some adjustments are done to its property. These adjustments are (a) Alteration of pH, (b) Alteration of air content (aeration), and (c) Addition of fertilizers. Acidity or alkalinity (pH) affects the ability of plant roots to take up minerals from the soil. A fertile soil should have somewhat neutral pH. Lime (calcium carbonate) is added to acidic soils to raise the pH (make soil more alkaline). Peat is added to alkaline soils to lower the pH (make soil more acidic). Soil with a low air content have high water content, and so are heavy and difficult to work. It can be improved by drainage of water from the soil of a given area and by ploughing. Fertilizers are added to soil which have low mineral content such as nitrate, phosphate, potassium, and magnesium.

10.

SOIL EROSION

Sometimes wind and water remove the fertile topsoil reducing the productivity of the soil in that area. This removal of soil by running water and wind is known as soil erosion. Generally, the rate of removal of fine particles from the surface is the same as the rate of formation of soil. But sometimes disturbance in this balance, usually man-made, lead to a greater rate of removal of soil. The major causes of soil erosion are:  Deforestation: The removal of trees on a large scale is known as deforestation. When trees are removed, soil particles are left loose and can be easily carried away by running water and wind

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6th Biology

37

 Overgrazing: Repeated grazing by animals on the same patch of land without sufficient recovery periods, leads to the removal of grass on a large scale. This makes it easy for wind and running water to erode the soil  Floods and heavy rainfall: Floods and heavy rainfall wash off soil, especially when there are no trees and the land is lying bare.  Improper farming: Improper farming on hills make it easy for wind and water to erode soil. PREVENTION OF SOIL EROSION Reduction or prevention of soil erosion is called soil conservation. The following are some of the measures that help in conserving soil:  Planting of trees in large numbers on deforested land (which is called afforestation). Grasses and herbs can be used to cover large patches of loose soil.  Overgrazing of a single patch by animals should be avoided. Animals should be moved to a different area after some time.  Floods can be controlled to a large extent by building dams. Embankment or mud walls should be constructed around hill slopes or fields to stop the flow of water.  Terrace farming should be adopted in hilly areas. In this method, suitable crops are grown on sloping ground which is cut into large steps called terraces. This reduces the speed with which water flows down, thereby reducing soil erosion. 11.

SOIL POLLUTION

Soil is one of the most valuable natural resources. It can get polluted by various means, including careless human activities. Necessary measures should be adopted to control soil pollution. The major sources of soil pollution are:  Acid rain and acid water from factories, mines, and industries.  Improper dumping of garbage and sewage wastes in soil.  Excessive use of pesticides and fertilizers, which get accumulated in soil.  Waste materials such as plastic and metals which do not decay easily.  Spilling or leakage of chemicals. Control of Soil Pollution The following measures will help to control soil pollution: • • • •

Solid wastes should not be dumped on land. They should be recycled and proper measures for disposal of sewage should be adopted. Animal and domestic wastes should be used to produce biogas (an ecofriendly fuel). Instead of chemical pesticides and fertilizers, organic pesticides should be used. Liquid wastes from factories and mines should be properly treated before they are released into water bodies such as rivers and lakes

SNAP SHOT 1. Soil is the uppermost layer of earth's crust, in which plants grow. 2. Soil is formed from the parent rock material by a very slow and gradual process called weathering. A number of agents - temperature changes, frost, water, wind and living organisms - are involved in the weathering of rocks. 3. There are three main layers or horizons in the soil profile - A-horizon (top soil), B-horizon (subsoil) and C-horizon (parent rock). 4. Soil consists of soil particles, humus (organic matter), water, air and living organisms.

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Soil

38

5.

Soil particles, depending on size, consist of clay (below 0.005 mm), silt (0.005 to 0.05 mm), sand (0.05 to 2.0 mm) and gravel (above 2.0 mm). 6. A soil containing a mixture of sand, silt and clay is called a loamy soil. It is the best soil for plant growth. 7. Six types of soil are mainly found in India - Red soil, black soil, alluvial soil, desert soil, mountain soil and laterite soil. Humus content is maximum in mountain soil. Black soils are rich for growing cotton and sugarcane while alluvial soil is suitable for wheat and rice. 8. Soil is an important natural resource. It provides us food, clothing, shelter, medicines, rubber, dyes and a number of other useful products. Besides man, it provides shelter to wildlife and different soil organisms. 9. Wind and rain bring about loss of the top soil (soil erosion). Deforestation, over-grazing and poor farming methods have accelerated the process of soil erosion. 10. Prevention of soil erosion (soil conservation) can be brought about by growing plants (afforestation), crop rotation, prevention of over-grazing, maintaining, proper drainage, and growing of crops in steps cut into mountain slopes in the hills (terrace cultivation).

Formative Worksheet 1.

2. 3.

4. 5.

6. 7. 8. 9.

10.

11. 12. 13.

(A) Soil formation is a ………………….. (fast/slow) process. (B) Rocks break up due to …………………..(only physical/physical and chemical) weathering. (C) ………………….. (Physical/Chemical) weathering is a mechanical process. (A) Microorganisms break down animal and plant remains to form ___________(soil/humus). (B) ___________ (Topsoil/Subsoil) is rich in humus. (A) In __________(physical/chemical) weathering, the chemical nature of the rock is not altered. (B) The difference in particle size of the soil constituents determines its __________ (texture/colour). (A) __________ (Clayey/Sandy) soil becomes sticky and plastic when wet. (B) __________ (Lime/Peat) is added to acidic soils to raise the pH. (A) The method of growing crops on steps in hilly regions is called _________ (terrace/improper) farming. (B) Reduction or prevention of soil erosion is called soil _________ (conservation/pollution). (A) The removal of trees on large scale is known as ________ (afforestation/deforestation). (B) _________ (Chemical/Organic) pesticides should be used to decrease soil pollution. From which layer of soil do plants get their nutrients? (A) Topsoil (B) Subsoil (C) Parent rock (D) Bedrock Which layer of soil determines the type of soil? (A) Topsoil (B) Subsoil (C) Parent rock (D) Bedrock Which of the following does not cause weathering? (A) Wind (B) Water (C) Lighting (D) Heating and cooling of rocks What are the four main layers in a soil profile? (A) Minerals, water, humus, and air (B) Topsoil, subsoil, pieces of rock, and bedrock (C) Loam, sand, silt, and clay (D) None Which is made up of decayed plants and animals? (A) Air (B) Minerals (C) Humus (D) Pebbles Type of soil that has the maximum water absorption tendency: (A) Clay (B) Loamy (C) Sand (D) Topsoil Soil erosion is (A) Soil pollution (B) Weathering (C) Soil formation (D) Removal of soil by wind and running water

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39

6th Biology

14.

Define the terms: (A) Soil (B) Humus (C) Soil profile (D) Weathering Give two main characteristics of: (A) Sandy soil (B) Loamy soil (C) Clayey soil Soil is classified on the basis of the proportion of particles of various sizes. If soil contains greater proportion of bigger particles, then it is known as i soil whereas if the proportion of finer particles is greater, then it is ii soil. The information in which alternative completes the given statement? (A) i- loamy ii- sandy (B) i- clayey ii- sandy (C) i- sandy ii- clayey (D) i- loamy ii- clayey Sandy soil is well aerated and drains water quickly when compared to clayey soil. This is because it contains soil particles that are (A) larger in size (B) smaller in size (C) rich in humus content (D) poor in humus content Which of the following agents is responsible for soil erosion? (A) Solar radiations (B) Soil organisms (C) River water (D) Plant roots Which of the following natural phenomena is not caused by human activities? (A) Acid rain (B) Global warming (C) Volcanic eruption (D) Ozone layer depletion Grasslands are big open spaces that are covered with grass but lack trees and heavy bushes. It is a region where large herds of grazing animals are commonly found. The speed of animals that are found in grasslands is extremely important for their survival. Which of the following animals is not found in grasslands? (A) Seal (B) Zebra (C) Giraffe (D) Bison Sand is not used to make vases because the soil particles are (A) Fine with air spaces (B) Large with air spaces (C) Fine and can retain water (D) Large and can retain water These weathering agents break down the rocks by its constant collision with the rocks. Which two agents are responsible for the process described in the above statement? (A) Organisms and wind (B) Sun and organisms (C) Wind and water (D) Water and Sun A certain soil type contains soil particles that are very large in size when compared to the soil particles of other soil types. The described soil is identified to be (A) Clay (B) Loam (C) Sand (D) Silt Rocks expand and contract continuously over a period of many years. This causes the rocks to break down leading to an important process called weathering. Which factor is responsible for the described phenomenon? (A) Organisms (B) Water (C) Wind (D) Sun Clayey soil is used to make items such as vases because it contains (A) Fine soil particles (B) Rough soil particles (C) Large soil particles (D) Loose soil particles Deforestation will increase the occurrence of which of the following events? (A) Snowfall (B) Soil erosion (C) Heavy rainfall (D) Depletion of ozone layer During the day, the rocks ____i_ _ while at night, they ____ii___ . This results in the formation of ____iii___. The information in which alternative completes the given statement? (A) i- expand ii- contract iii- mountains (B) i- expand ii- contract iii- cracks (C) i- contract ii- expand iii- cracks (D) i- contract ii- expand iii- mountains Reena was making notes of the chapter ‘Soil’. She wrote down the given points from the chapter. I. The formation of soil is independent of climate of an area. II. Water helps in the formation of soil. III. Soil contains small particles of rocks. IV. The top soil and the sub-soil contain humus. However, she later realised that she had made some mistakes in her notes.

15. 16.

17.

18. 19.

20.

21.

22.

23.

24.

25.

26.

27.

28.

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Soil

40 Which of the following pairs of statements is incorrectly written by Reena? (A) I and II (B) II and III (C) II and IV (D) I and IV

Conceptive Worksheet 1.

2.

3. 4.

5.

6.

7. 8.

9.

10.

11.

12.

Which of the following is a mixture of decomposed organic matter and is usually dark in colour? (A) Clay (B) Humus (C) Podzol (D) Loam Which of the following describes hygroscopic water? (A) Water held as a tight film around individual soil particles and unavailable to plants (B) Water which is available to drain through the soil by gravity (C) Water which ponds up on the soil surface (D) Water which represents the majority available for plant uptake Soil acidity is measured by the concentration of which cation? (A) Sodium (B) Magnesium (C) Hydrogen (D) Calcium In which condition do organic acids cause iron to be transported downward through the soil profile? (A) Podzolisation (B) Laterisation (C) Gleying (D) Salinisation Which system is commonly used to describe the colour of a soil? (A) Fluorimeter (B) Munsell Colour Chart (C) FAO Soil classification chart (D) USDA Soil type table From which elements are clay minerals formed? (A) Sodium and Potassium (B) Hydrogen and Oxygen (C) Calcium and Aluminium (D) Aluminium and Silicon How many essential elements are there without which green plants cannot grow normally? (A) 6 (B) 56 (C) 16 (D) 19 Why are cations attracted to clay minerals? (A) Because of the temperature gradients (B) Because of electrostatic attractions (C) Because no other minerals will bond with cations (D) Because clay minerals are the largest soil particles How much more carbon do soils store than the atmosphere? (A) Ten times as much (B) Half (C) One third (D) Twice as much Why is it important to apply nitrogen fertiliser at an appropriate time of year? (A) The fertiliser only works above 10°C (B) Fertiliser requires a threshold level of soil water to work (C) During winter, nitrate is more easily leached from the soil when there is no vegetation cover (D) Fertiliser is more expensive during certain months of the year Which of the following practices will not help in preventing soil erosion? (A) Planting trees and grasses (B) Practising terrace farming (C) Constructing strong embankments (D) Adding fertilisers and manures to soil Consider the following statements regarding the types of soil. I. Sandy soil can retain more air than clayey soil. II. Clayey soil can retain more water than loamy soil. III. Loamy soil can retain less water than sandy soil. Among the given statements,

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41

6th Biology

13.

(A) only I is correct (B) only III is correct (C) both I and II are correct (D) both II and III are correct Soils are classified as sandy, loamy or clayey depending on the relative size of the particles. Which of the following tables correctly matches the soil type with its relative particle size? (A) Soil type Relative size of particles (B) Soil type Relative size of particles Loamy

Large

Loamy

Small

Sandy

Mixture of both large and small

Sandy

Large

Clayey

Small

Clayey

Mixture of both large and small

(C) Soil type Relative size of particles

14.

15.

16.

(D)

Soil type

Relative size of particles

Loamy

Mixture of both large and small

Loamy

Small

Sandy

Large

Sandy

Large

Clayey

Small

Clayey

Mixture of both large and small

The given diagram illustrates the various layers of rock.

If the fossils of dinosaurs are found in layer II, then the fossils of modern day reptiles are most likely to be found in which layers? (A) I, II (B) II, III (C) III, IV (D) IV, I Joyeeta collects a sample of soil from an area. She observes that the soil is composed of sand, clay, gravel and humus. She mixes the soil into a glass of water and allows the mixture to settle down. She observes that different components settle in different layers in the glass. Which of the following arrow diagrams correctly represents the sequence in which the different components settle in the glass, starting from the topmost layer? (A) Clay → Gravel → Water → Sand → Humus (B) Humus → Sand → Water → Gravel → Clay (C) Humus → Water → Clay → Sand → Gravel (D) Gravel → Sand → Clay → Water → Humus Which of the following agents is responsible for soil erosion? (A) Solar radiations (B) Soil organisms (C) River water (D) Plant roots

Summative Worksheet I. 1.

2. 3. 4.

Multiple choice questions. The process of soil formation is called (A) Conservation (C) Erosion Soil profile consists of (A) Two layers (B) Three layers Parent rock material is present in (A) A-horizon (B) B-horizon Humus is present in (A) A-horizon (B) B-horizon

(B) Weathering (D) None of the above (C) Four layers

(D) Five layers

(C) C-horizon

(D) bed rock

(C) C-horizon

(D) bed rock

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Soil 5.

42 Soils best suited for plant growth are (A) Loamy (C) Sandy

(B) Clayey (D) None of the above

II. (i) (ii) (iii) (iv) (v) (vi) (vii) (viii)

Write true or false in front of the statements given below A fertile soil is rich in humus. Sandy soils are best suited for plant growth. A clayey soil has more proportion of fine particles. Capillary water is the water available to the plants for absorption. Dark coloured soils are rich in organic matter. Proper drainage in a field helps to prevent soil erosion. Crop rotation enriches soil fertility. Over-grazing is a means of soil conservation.

III. 1. 2. 3. 4. 5. 6. 7.

Fill in the blanks: Clay particles range in size from to _____________________ . Humus is present in _____________________ horizon of the soil profile. A-horizon is also known as _____________________ Bed rock is found below the horizon _____________________. Planting of trees is called _____________________. Red colour of soil is due to _____________________. Humus content is the highest in _____________________ soil.

IV. 1. 2. 3. 4. 5. 6. 7. 8.

Define the following: Soil Weathering Soil erosion Loam Soil texture Humus Terrace cropping Residual soil

V. 1. 2. 3.

Answer the following questions: Which soil horizon is rich in humus? Which type of soil is best suited for growth of plants? Give reasons in support of your answer. What is meant by soil profile? Give the characteristics of different horizons observed in the soil profile. With the help of a diagram, illustrate the soil profile. How is soil formed? Describe in brief. Name the different types of particles present in soil. Describe the various types of soils and the basis of their classification. Describe the composition of soil. Mention the characteristics of mountainous soil and black soil. Distinguish between sandy, clayey and loamy soils. Distinguish between residual and transported soils. How is soil important to us? Explain. Describe the factors which cause soil erosion. How can soil erosion be prevented?

4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14.

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Learning Outcomes

Fossils



Know about fossils and their formation



Know about the significance of fossils



Describe the types of fossil fuels

1.

INTRODUCTION

We know that many of the living forms that lived millions of years ago no longer exist today. A very well known example is that of dinosaurs, who existed long ago in large number. They do not exist now. Many such organisms which existed in the past have left their remains or impressions on rocks, on the sea beds, or in the layers of the earth. These 'remains' or 'impressions' of organisms are called fossils (Figure. 4.1). Fossils are the remains of dead plants and animals which existed millions of years ago and got buried in the earth.

Chapter -4

By the end of this chapter, you will understand

Figure 4.1: Different fossils

Our earth, from its surface to the centre shows three major regions: (i)

the uppermost layer is called the crust,

(ii)

the middle layer, as the mantle, and

(iii) the central part, as the core. Earth's crust, up to 35 to 65 km in thickness, consists of three types of rocks - igneous, sedimentary and metamorphic. Earth's crust is the most important layer, as discussed in the previous chapter. Fossils are present in sedimentary rocks. The branch of science dealing with the study of fossils is called palaeontology. (palaeo = ancient, onto = individual and logos = science) 2.

FORMATION OF FOSSILS

Fossils are rare since most organisms after their death disintegrate (decay) and quickly disappear. However, under certain conditions, the hard parts of organisms are preserved as fossils, in the following way (Figure. 4.2). In some cases, a dead organism or its parts get buried under sediments of sand and other minerals. The sediments keep depositing over a period of time. The soft parts decay but the hard ones survive and absorb minerals. These minerals gradually replace the hard parts of the organisms, and convert them into hard stone, the fossil. The fossils with time get covered with additional layers of sediments. The deep sediments get converted into sedimentary rocks. Due to the movements of the earth's crust, millions of years later, these rocks with the fossils may be pushed upwards. The fossils subsequently may be exposed by cracking or faulting of the rocks (Figure. 4.2). Sedimentary rocks are formed b the deposition and compression of rock sediments. During this deposition of rock sediments, organisms also get buried; hard parts of the plants get converted into fossils.

Fossils

44

Living fish

Fossil

(A) Surface erosion and sedimentation

(B) Sedimentation and sedimentary rock

(C) Fossils in sedimentary rock

Figure 4.2: Formation of fossils 3.

SIGNIFICANCE OF FOSSILS

Fossils tell us a lot about the living things which lived in the past, and how they changed. The earth's surface consists of layers of rock. The fossils in each layer act as a record of the life that existed at that time. The more recent fossils will be present in the rock layers nearer to the surface. 4.

FOSSIL FUELS

A substance which on burning produces a lot of heat is called a fuel. Wood, coal, kerosene, petroleum are some of the important fuels. However, the fuels which are formed from the remains of plants and animals which got buried millions of years ago are called fossil fuels. Coal, petroleum and natural gas are the main fossil fuels. Fossil fuels are present in the Earth in limited quantities, and very soon, these reserves will be exhausted. Because of their inability of regenerate fast enough, fossil fuels are termed nonrenewable sources of energy. For this reason, we need to conserve these fuels by using them carefully and avoiding wastage. DRAWBACK OF USE OF FOSSIL FUELS Burning of fossil fuels releases carbon dioxide in the air. This causes air pollution and thus harms the environment. COAL (i)

The period between 200 to 300 million years ago is known as the carboniferous age.

(ii)

During this period, large trees were present in abundance on the Earth. The trees on death got buried in the Earth.

(iii) Very slowly, these trees got converted into peat, then lignite and finally coal. (iv) Chemically, coal is largely made up of complex compounds of carbon along with some rocky material. PETROLEUM (i)

Petroleum, also called crude oil, is formed from the remains of living organisms (which got buried millions of years ago) in water. It takes several million years to form.

(ii)

Petroleum is a complex mixture of solid, liquid and gaseous hydrocarbons (compounds of carbon and hydrogen) mixed with salt water and earthly particles. It is mostly found in sedimentary rocks, and is obtained by drilling in these rocks.

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6th Biology

45

(iii) Petroleum on refining by distillation gives several fractions such as petroleum gas, naphtha, petrol (or gasoline), diesel, kerosene, lubricating oil, wax, heavy oil. NATURAL GAS (i)

Natural gas was formed along with petroleum millions of years ago from the remains of living organisms which got buried under the Earth.

(ii)

Natural gas consists of 95% methane, and the rest 5% consists of ethane, propane and ethylene.

5.

ENERGY CRISIS

Thousands of years ago people had only the sun's energy and their own energy. They burnt wood (from plants) for heat and animals provided energy to carry things and to work on the farms. Subsequently, they learnt to use energy in the wind to drive wind-mills and sail ships. About 200 years ago, coal burning steam engines began to drive factory machines and the railway locomotives. Now, we have petrol-driven cars and planes, which provide us fast and convenient mode of transport. Also, we have electricity which provides energy for our homes, offices and factories. Energy needs of humans are increasing day by day because of its use to provide comforts of modern life. Increasing population, leading to growth of cities, and technological advancement resulting in setting up of more and more industries, transport and modernization of agriculture are factors putting a heavy demand on energy consumption. Because of increased demand and limited resources, imports of oil and petroleum products are increasing every year. The indiscriminate use of energy sources without developing proper alternative sources of energy is leading to an energy crisis. SNAP SHOT 1. 2. 3. 4. 5. 6. 7. 8.

Fossils are the remains of dead plants and animals which existed millions of years ago. Fossils are formed when plants and animals get buried in the sediments of sand and other minerals. Fossils are important as they tell us about the living things which lived in the past, and how the living things have changed with time. Fuels which are formed from the remains of plants and animals which got buried millions of years ago are called fossil fuels. Coal, petroleum and natural gas are the main fossil fuels. Fossil fuels represent non-renewable sources of energy. Excessive consumption of fossil fuels has led to an energy crisis. Fossil fuels cause pollution and are, therefore, bad for the environment.

Formative Worksheet 1.

The illustration represents a cross section of a sedimentary rock. Which of the following statements regarding the relative ages of fossils in the given illustration (A) Fossil I is the oldest (B) Fossil VII is the youngest (C) Fossil V is younger than fossil VI (D) Fossil III and fossil IV are of same age

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Fossils

46

2.

The illustration represents a cross section of a sedimentary rock. Which of the following statements regarding the relative ages of fossils in the given illustration (A) Fossil I is older than fossil III. (B) Fossil III is younger than fossil II. (C) Fossil IV and fossil V are of same age. (D) Fossil V and fossil VII are of same age.

3.

Consider the following statements regarding fossil fuels. I Fossil fuels are the dead remains of living organisms that have been buried for a long time. II Excessive use of fossil fuels causes global warming and a depletion of natural resources. III Earthquakes occur as a result of burning fossil fuels. Among the given statements, (A) Only statement I is true (B) Only statement III is true (C) Statements I and II are true (D) Statements II and III are true The illustration shows a cross section of a sedimentary rock with fossils in different layers of the rock. Which fossil is the oldest? (A) I (B) II (C) III (D) IV

4.

5.

6.

The fossil of an organism was discovered in bedrock. The fossil had scales all over the body and it also had clawed digits. To which of the following organisms does the fossil belong? (A)

(B)

(C)

(D)

A group of scientists found fossil impressions of fins and scales. To which of the following organisms does the fossil belong? (A)

(B)

(C)

(D)

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47

6th Biology

7.

An excessive use of fossil fuels can lead to the (A) Destruction of buildings (B) Depletion of natural resources (C) Reduction of global temperature (D) Reduction in electricity production The illustration represents a cross section of a sedimentary rock. Which of the following statements regarding the relative ages of fossils in the given illustration is true? (A) Fossil I and II are the oldest. (B) Fossil VI and VII are the oldest. (C) Fossil III and IV are of the same age. (D) Fossil III and V are of the same age. Fossils play an important role in studying the process of evolution. What are fossils? (A) They are fresh remains of dead plants and animals (B) They are preserved remains of dead plants and animals (C) They are living body parts of living plants and animals (D) They are preserved body parts of living plant and animals While digging through a sedimentary rock, a group of scientists discovered fossils of different types of animals. They first found the fossils of a mammal, then of a bird, then an amphibian, and finally they found the fossils of fish. Which fossil is the oldest among the mentioned fossils? (A) Amphibian (B) Mammal (C) Bird (D) Fish It is advisable that we reduce our usage of conventional sources of energy and use non conventional sources instead. However, when compared to the conventional sources of energy the non-conventional sources (A) Have lesser calorific values (B) Release greater toxic gases (C) Are in greater danger of getting exhausted (D) Pose a more serious threat to the environment Use of fossil fuels must be avoided because (A) Their energy output is low as they have been kept unused for millions of years (B) They use oxygen from atmosphere for burning which can cause its depletion (C) They produce solid wastes that are harmful for environment (D) Their use produces gases that enhance greenhouse effect Scientists find various fossils of a particular prehistoric mammal in successive layers of sedimentary rocks. But, as they moved closer to surface, after a few layers (spanning around 10,000 years) the fossils of that mammal disappeared. The disappearance of the fossils indicates the period when (A) Sediment formation stopped (B) The mammal became extinct (C) The mammal was heavily preyed upon (D) Earth was not undergoing any changes Which of the following sources of energy is not environment friendly? (A) Water (B) Coal (C) Wind (D) Sunlight Which of the following characteristics is not that of fossil fuels? (A) They are renewable. (B) They are exhaustible. (C) They cause pollution. (D) They take many years to form. The illustration represents a cross section of a sedimentary rock. Which of the following statements regarding the relative ages of the fossils in the given illustration is true? (A) Fossil I is older than fossil II. (B) Fossil IV is older than fossil I (C) Fossil II is older than fossil III. (D) Fossil III is older than fossil IV.

8.

9.

10.

11.

12.

13.

14. 15.

16.

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Fossils

48

Conceptive Worksheet 1.

Some fuels do not affect the environment, while the use of other fuels cause air pollution and affect the environment The use of which of the following sources of energy will affect the environment? (A) Coal (B) Hydro (C) Solar (D) Tidal

2.

Scientists excavated a fossilized branch of a plant. The fossil showed the presence of a cone on the branch. The observed features of the fossil suggest that it is an ancestor of (A) Ferns (B) Pines (C) Mosses (D) Mangoes

3.

A group of scientists excavated a fossil from an excavation site. The fossil is shown in the given figure. The observed features of the fossil suggest that it is an ancestor of (A) Birds (B) Fishes (C) Humans (D) Rats

4.

A liquid X, also called black gold, has two constituents − Y and Z. Y is used as a rocket propellant and Z is used in road surfacing. X, Y, and Z are respectively

5.

6.

7.

8.

9.

(A) Petroleum, kerosene, and bitumen

(B) Petroleum, diesel, and bitumen

(C) Petrol, kerosene, and diesel

(D) Petrol, LPG, and diesel

The combustion of fossil fuels releases oxides of i and ii . These oxides combine with water vapours in the atmosphere and eventually cause acid rain. The information in which alternative completes the given statement? (A) i- carbon ii- sulphur

(B) i- sulphur ii- nitrogen

(C) i- carbon ii- chlorine

(D) i- sulphur ii-chlorine

Fossil fuels cannot be used to (A) Run turbines

(B) Produce electricity

(C) Fuel motor vehicles

(D) Minimize greenhouse effect

Which of the following observations provides evidence that organisms existed in the past? (A) Feather impression in bedrock

(B) Photosynthesis by leaves

(C) Meteors falling on Earth

(D) Respiration by animals

Which of the following observations does not provide evidence that organisms existed in the past? (A) Insect in amber

(B) Animal in the zoo

(C) Footprints on the rocks

(D) Feather impression in bedrock

The use of fossil fuels (A) Reduces the chances of acid rain (B) Leads to a decrease in the greenhouse effect (C) Reduces the level of carbon dioxide in the air (D) Leads to a depletion of the conventional energy sources

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49

6th Biology

10.

Scientists throughout the world gather new evidences to form ideas about what organisms lived on Earth in the past. Which of the following observations provide evidence that organisms existed in the past? (A) Animals living in zoo (B) Bones found in bedrock (C) Meteors that fall on Earth (D) Occurrence ofseeds in fruit Which of the following objects are not used to determine that organisms existed in the past? (A) Fossils (B) Meteors (C) Claws in tar pits (D) Footprints on rocks

11.

12.

The illustration represents a cross section of a sedimentary rock. Which fossil is the oldest? (A) I (B) II (C) III (D) IV

13.

Plant X grows in saline water. Plant Y grows in fresh water. Under certain conditions both plants X and Y become dry. Plants X and Y become dry when (A) Plant X is grown in pond water and plant Y is grown in sea water (B) Plant Y is grown in pond water and plant X is grown in sea water (C) Both plants X and Y are grown in sea water (D) Both plants X and Y are grown in pond water Some scientists observed a section of a sedimentary rocks and found different fossils in the different layers of the rock. The fossils that are younger than fossil III are (A) Fossil I and fossil II (B) Fossil IV and fossil V (C) Fossil I and fossil IV (D) Fossil II and fossil V

14

15.

Some scientists observed a section of a sedimentary rock and found different fossils in the different layers of the rock. Which of the following statements is true regarding the relative ages of fossils in the given illustration? (A) Fossil I is younger than fossil II, III, and IV. (B) Fossil II is younger than fossil I, III, and IV. (C) Fossil III and fossil I are of the same age. (D) Fossil IV and fossil II are of the same age.

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Fossils

50

Summative Worksheet I.

Multiple choice questions.

1.

Coal and petroleum are

2.

(A) Fossils

(B) Formed by Sun's energy

(C) Fossil fuels

(D) None of the above

Fossils (A) Are of recent origin (B) Are formed from living organisms that lived millions of years ago (C) Do not represent living forms (D) Are none of the above

II.

Fill in the blanks:

1.

Fossils are present in _________________ rocks.

2.

Three main fossil fuels are , _________________ and _________________.

3.

Fossil fuels, because of their inability to regenerate quickly, are called _________________ resources of energy.

III. Answer the following questions: 1.

Define fossils.

2.

How are fossils formed?

3.

Mention the significance of the study of fossils.

4.

What are fossil fuels?

5.

Name three fossil fuels.

6.

Name the ultimate source of energy for fossil fuels.

7.

Why are fossil fuels considered nonrenewable sources of energy?

8.

Why should we not use fossil fuels?

9.

Write briefly about the following fossil fuels: (i) Coal, (ii) Petroleum, (iii) Natural gas

10.

What is meant by energy crisis?

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By the end of this chapter, you will understand  Describe different parts of a plant  Identify a tap root, fibrous root, simple leaf and a compound leaf  Describe the functions of different plant parts  Know about the modifications in roots, stems and leaves  Describe the structure of a flower  Know about the role of a flower in reproduction  Describe pollination and differentiate between self and cross pollination  Learn about fertilisation and the steps leading to the formation of seeds and fruits  Know about the structure of a fruit  Describe the various means by which dispersal of seeds and fruits takes place

STRUCTURE AND FUNCTIONS OF PLANT PARTS

Chapter -5

Learning Outcomes

Life is impossible without flowers and flowering plants. Nine-tenths of that part of the world that is covered with vegetation is covered with flowering plants. In this chapter, we are going to study about the structure of a flowering plant and the modifications. which the various plant organs have undergone to ensure their survival. 1. CELLS TO ORGANISMS We know, basic structural unit of living organisms, the cell, was described. Let us see how the cells are organized to form the multicellular body of living organisms. Cells in multicellular organisms are not similar. Rather they are specialized to perform different functions. For example, nerve cells are specialized to conduct messages while muscle cells are specialized to conduct and help in locomotion. The specialized cells which group together to perform a particular function are known as a tissue. A tissue represents a group of cells similar in structure and function. Different tissues are often grouped together into larger units called organs. An organ, thus, consists of several different tissues. For example, stomach is an organ to digest food, and is made up of different tissues like epithelial and muscular tissues. Similarly, heart is an organ consisting of muscular and nervous tissues. Likewise in plants, the root, stem, leaves and flowers are the different organs which perform different functions and consist of various tissues. Organs, in turn, are organized into organ-systems. An organ-system consists of different organs that function together. For example, the digestive system consists of various organs like the mouth, stomach, intestine, liver, pancreas and rectum which perform the role of digestion of the ingested food. Different organ-systems comprise the multicellular organism. This organization of cells into tissues, organs, organ-systems and the organism is found in all multicellular organisms - plants as well as animals.

Structure and Functions of plant parts

52

2. PARTS OF A FLOWERING PLANT We have studied earlier that a flowering plant may be a herb, shrub or a tree. Now collect a herb along with its underground parts. Having collected a herb, see into what parts can you divide this plant. A flowering plant can be divided into two parts (Figure. 5.1) : (i) An underground part called the root system, and (ii) An above ground part called the shoot system. The root system consists of the roots, while the shoot system consists of the stem, branches, leaves, flowers and fruits. The root, stem and leaves constitute the vegetative parts of a plant body. The shoot system also bears the flowers and fruits which comprise the reproductive parts. 3. THE ROOT SYSTEM The part of the plant body which fixes it to the soil is called the root system. In certain plants like mustard, gram, pea, balsam, tulsi, marigold, rose, oleander, mango and neem, the root system consists of a main root called the tap root (Figure. 5.2) and its branches. The tap root grows vertically down into the soil and then gives out branches. In some plants like wheat, maize, millets, other grasses, sugarcane and banana, there is no main root. A number of roots arise in a cluster below the stem and spread out in the soil. Such roots are called Fibrous root fibrous roots (Figure. 5.3).

Figure 5.1: Parts of flowering plant

FUNCTIONS 1. Roots fix the plant to the soil. 2. Roots absorb water and mineral salts from the soil which are then conducted upwards to the stem and leaves. 3. Roots help in holding the soil together, thus, preventing erosion or blowing away of the soil particles. 4. In some plants, roots are modified to perform additional functions of storage, support or respiration.

Figure 5.2: Tap root

Figure 5.3: Fibrous root

MODIFICATIONS OF ROOT FOR STORAGE In plants like sweet potato, radish, carrot, turnip and beet root, the roots instead of spreading in the soil, become swollen [Figure. 5.4 (a), (b), (c)]. These swollen roots store food, which we eat. Such roots are called tuberous roots.

Figure 5.4(a) Modified root of Turnip

(b) Modified root of Sweet potato

(c) Modified root of Caroot

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6th Biology

53

MODIFICATIONS OF ROOT FOR ADDITIONAL SUPPORT In the Botanical Garden at Kolkata, a 200 year old banyan (bargad) tree which has a crown circumference of more than 400 metres is present. In banyan, a number of roots arise from the tree branches and these roots grow downwards. These roots are called supporting roots or prop roots. These act as pillars and support the big heavy horizontal branches (figure 5.5). Maize and sugarcane also have supporting roots.

Figure 5.5: Supporting roots of Banyan tree

Figure 5.6: Breathing roots in mangrove plant

MODIFICATION OF ROOT FOR RESPIRATION In certain plants growing in saline marshy habitats, the root system produces vertically upward growing branches above the soil. These roots help in respiration and are known as breathing roots or pneumatophores, as found in mangrove plants like Rhizophora (Figure 5.6). 4. THE STEM Stem forms the main axis of the plant body. It is divided into nodes and internodes. The place from where the branches and leaves arise on the stem is called the node. The portion of the stem between two nodes is called the internode. The tip of the stem or a branch bears an apical or terminal bud (Figure. 5.7). Apical bud helps in lengthwise growth of the plant, that is, it leads to an increase in the height of the plant body. Buds are present in the axils of leaves too. These buds are called axillary buds. They grow into branches. When young, a stem is green and soft. In an herb, the stem remains soft and tender. But in a tree, it becomes hard and Figure 5.7: Buds woody and is called the trunk. It is no longer green. It becomes brownish in colour, and is in fact covered with bark. The bark protects the inner parts of the tree. In some plants, the stem is very weak and needs a support to stand erect and grow. Such plants are called climbers. Grapevine, sweet pea and cucurbita are some examples of climbing plants. FUNCTIONS 1. A stem bears the leaves, flowers and fruits. It serves as a link between the roots, the leaves and flowers. 2. The stem and its branches hold the leaves in such a manner that the leaves get maximum possible sunlight. 3. When young, it is green and manufactures food through the process of photosynthesis. 4. It carries water and mineral salts from the roots to the leaves and flowers. 5. It carries food manufactured in the leaves to roots and other parts of the plant body. 6. In some cases, the stems may be modified to perform the functions of storage, foodmanufacture (photosynthesis), and support.

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Structure and Functions of plant parts

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MODIFICATIONS OF STEM FOR STORAGE (a) In some plants, the stems are underground. The underground stems are modified to store food materials, and help the plant to survive unfavourable conditions. The underground modifications are stems, as they possess nodes and internodes. The main modifications are as follows: (i) Tuber : Look at a potato. It is a small, thick and fleshy structure. It has buds which are called 'eyes'. It also has some scaly leaf-like structure (Figure. 5.8 a). This swallen structure which stores food (in the form of starch) is called a tuber. New plants develop from the 'eyes' of the tuber. (ii) Bulb : Observe an onion (Figure. 5.8 b). It is a thick, bulb-like structure. The stem is short and bears small fibrous roots at the base and Figure 5.8 (a): Tuber of potato leaves above. The outer leaves are dry and scaly (scale leaves). The outer dry scales enclose thick fleshy leaves which store food. (iii) Rhizome : In plants like ginger and turmeric, food is stored in underground stems called rhizomes (Figure. 5.8 c). In a piece of ginger (adrak), we will find nodes and internodes, brown scale leaves arising from nodes, small buds and adventitious roots.

Figure 5.8 (b): Bulb of onion (b)

Figure 5.8 (c): Rhizome of ginger

In cactus plant (Figure. 5.9), the stem becomes fleshy and green. The stem prepares food and also stores water for long periods. The leaf is reduced to spines. Prickly poppy (Opuntia) is another such type of plant.

Figure 5.9: A cactus plant; the stem prepares food MODIFICATION OF STEM FOR PHOTOSYNTHESIS Look at the cactus plant again. In addition to the stem being fleshy, it is green, too. The green stem performs the functions of the leaf. It manufactures food for the plant. Leaves are reduced to spines.

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6th Biology

55 MODIFICATION OF STEM FOR SUPPORT In climbers like grape vine, cucurbita, gourd or passion flower, the stem is very weak and needs support (Fig. 5.10). The thread-like structures are called the stem tendrils as these are modifications of stem. The tendrils coil around any object in the neighbourhood and thereby help the plant to climb up. Figure 5.10: Tendrils

1. 2. 3. 4. 5.

Table 5.1: Differences between Root and Stem Root Stem Develops from radicle. 1. Develops from plumule. Nodes and internodes absent. 2. Nodes and internodes present. Never green. 3. Often green. Leaves and buds absent. 4. Bears leaves and buds. Generally develops below ground. 5. Generally develops above ground.

Formative Worksheet 1.

The given figure illustrates parts I, II, and III of a potted plant. The conduction of water in the plants takes place by the part(s) labelled (A) I only (B) II only (C) I and II both (D) II and III both

2.

Which labeled structure provides support to the plant? (A) 1 (B) 2 (C) 3 (D) 4

3.

The type of root in which all parts of the roots are similar is called i . It is found in ii plants. The information in which alternative completes the given statements? (A) i- fibrous root ii- gram (B) i- tap root ii- maize (C) i- tap root ii- Gram (D) i- fibrous root ii-maize The type of root that has one main root and many smaller roots arising from the main root is known as i . It is found in ii plants. The information in which alternative completes the given statements? (A) i- fibrous root ii-gram (B) i-taproot ii- maize (C) i- taproom ii-gram (D) i-fibrous root ii-maize The fibrous root arises from (A) Secondary roots (B) Primary roots (C) Stem (D) Leaf A plant comprises stem, roots, leaves, flowers, fruits, and seeds. Roots help in (A) Transporting water and nutrients (B) Absorbing water and nutrients (C) Manufacturing food (D) Producing seeds

4.

5. 6.

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Structure and Functions of plant parts 7.

8.

9.

10.

11.

11.

12. 13. 14. 15. 16.

17.

56

Roots do not perform the function of (A) Distributing nutrients to all plant parts (B) Absorbing water from soil (C) Anchoring plants in soil (D) Storing food Which of the following functions is not performed by the roots of a plant? (A) Storage of food (B) Absorption of water (C) Anchoring the plant (D) Manufacture of food i perform the function of ii and anchoring the plant to the soil. The information in which alternative completes the given statement? (A) i-leaves ii-water conduction (B) i-stems ii-photosynthesis (C) i-roots ii-water absorption (D) i-flowers ii-transpiration In an experiment, Abhishek took two pots filled with soil and labelled them as I and II. Then, he took two marigold plants. He removed the roots of one marigold plant and placed it in pot I. He kept the roots of the other plant intact and placed it in pot II. He watered the two plants regularly and observed for any change. Which of the following statements regarding plants in pots I and II is correct? (A) The plant in pot I will die (B) The plant in pot I will remain healthy (C) The plants in both pots I and II will die (D) The plants in both pots I and II will remain healthy In an experiment, Neeta planted two rose plants in pots I and II. The plant in pot I was planted with roots and the plant in pot II was planted without roots. She watered the two plants regularly and placed them in sunlight. After ten days, the changes were observed. Which of the following statements regarding the observations made by Neeta after ten days is true? (A) Both plants in pots I and II die (B) Both plants in pots I and II remain healthy (C) The plant in pot I dies, while the plant in pot II remains healthy (D) The plant in pot I remains healthy, while the plant in pot II dies Water and nutrients are essential for plant life. The roots absorb water and nutrients from the soil. The plant in pot I is healthy because the roots of the plant are intact and thus, absorb water and nutrients from the soil. The plant in pot II dies because the roots of the plant have been removed. The plant is unable to absorb water and nutrients from the soil and therefore, it dies, despite being watered regularly. The correct answer is D. In which of the following, the food stored in roots? (A) Turnip (B) Carrot (C) Sweet potato (D) All Which of the following as prop roots? (A) Neem (B) Banyan (C) Eucalyptus (D) All Pneumatophores are found in (A) Pea (B) Ficus (C) Rhizophora (D) Asparagus Which part of a plant allows it to be erect? (A) Stem (B) Leaf (C) Root (D) Flower Which of the following statements about the primary function performed by the stem is correct? (A) It performs photosynthesis. (B) It anchors the plant to the soil. (C) It absorbs water and nutrients from the soil. (D) It conducts water and nutrients to the leaves. i helps in the conduction of ii to the leaves. The information in which alternative completes the given statement? (A) i-stem ii-water (B) i-stem ii-food (C) i-root ii-water (D) i-root ii-food

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57

6th Biology

18.

A student planted four plants I, II, III, and IV of same type as shown in the figure for one of his research projects. He ensured similar environmental conditions and nutrient supply for all.

19.

20. 21. 22.

Among the given plants, (A) Only plants I and III will survive (C) Plants III, IV and V will survive The stem forms the main trunk of a plant body. associated with the stem? (A) Provide oxygen (B) Distribute water Tuber is found in (A) Potato (B) Onion Bulb is found in (A) Potato (B) Onion The underground stem of ginger is called (A) Tuber (B) Bulb

(B) Only plants I and II will survive (D) Plants I, II, and III will survive Which of the following functions is not (C) Provide support (D) Distribute food (C) Garlic

(D) Ginger

(C) Garlic

(D) Ginger

(C) Rhizome

(D) all

Conceptive Worksheet 1.

The given diagram illustrates a plant. Absorption of water and nutrients from the soil is a function of which labelled structure? (A) I (B) II (C) III (D) IV

2.

The part of plant that fixes it to the ground in known as the (A) Stem (B) Root (C) Leaves (D) Flower i plant has fibrous roots and has ii venation in the leaves. The information in which alternative completes the given statement? (A) i- Maize ii- reticulate (B) i- Mango ii- parallel (C) i- Maize ii- parallel (D) i- Mango i- reticulate Plant A differs from plant B because plant A has

3.

4.

5.

(A) Tap roots (B) Storage roots (C) Fibrous roots (D) Climbing roots Every plant part performs a specific function for the plant. The plant part that absorbs nutrients for the plant is its (A) Stem (B) Fruit (C) Root (D) Leaf

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Structure and Functions of plant parts 6.

7.

58

Roots are an important part of the plant body. What is the primary function of roots? (A) Absorbing water and nutrients from the soil (B) Conducting water and minerals to the leaves (C) Preparing food by the process of photosynthesis (D) Producing oxygen by the process of photosynthesis The plant part labeled X performs the function of (A) Distribution of nutrients (B) Absorption of water (C) Photosynthesis (D) Reproduction

8.

The modified swollen roots of carrot are called (A) Prop roots (B) Pneumatophores (C) Breathing roots (D) Tuberous roots

9.

The areal supporting roots are (A) Prop roots (B) Pneumatophores (C) Breathing roots (D) Tuberous roots Which of the following are found in mangrove plants like Rhizophora? (A) Prop roots (B) Pneumatophores (C) Breathing roots (D) Tuberous roots In plants, distribution of food is carried out by (A) Stems (B) Roots (C) Leaves (D) Flowers Which part of a plant helps in the transportation of the food prepared by the leaves to various other parts of the plant’s body? (A) Stem (B) Root (C) Petal (D) Stamen The main function of stem is to (A) Distribute nutrients (B) Absorb nutrients (C) Produce pollen (D) Produce food The given diagram illustrates a sunflower plant. The function of the structure labelled I in the given diagram is to (A) Conduct water and minerals from the roots to the leaves (B) Prepare food by the process of photosynthesis (C) Absorb water and minerals present in the soil (D) Anchor the plant firmly to the soil

10.

11. 12.

13.

14.

15. 16. 17.

18.

Tuber stores food in the form of __________ in potato. (A) Carbohydrates (B) Fats (C) Proteins (D) Starch Stem is underground in (A) Potato (B) Onion (C) Garlic (D) Ginger Which of the following is true for opuntia? (A) Stem is green in colour (B) Leaves are reduced to spines (C) The stem is fleshy (D) All The thread like structures present in grape wine and cucurbita plants are called (A) Scales (B) Wires (C) Tendrils (D) Roots

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6th Biology

59 5. THE LEAF A leaf is a flattened green structure. It arises from the node of a stem or its branches. Leaves differ in shape and size. The flat green part of a leaf is known as the leaf blade or lamina. It is attached to the stem by means of a short stalk called the petiole (Figure. 5.11). The region of attachment of the leaf with the stem is called the leaf base. The leaf blade has many fine veins forming a network throughout its body. The arrangement of veins in the leaf blades is called venation. Leaves contain a pigment called chlorophyll. This pigment imparts green colour to the leaves.

Figure 5.11: Structure showing parts of a leaf

FUNCTIONS (1) Leaves manufacture food for the plant body. The process of manufacturing food by the leaves is called photosynthesis. Leaves require water, carbon dioxide, sunlight and chlorophyll for making food. (2) The leaves on their surfaces carry tiny pores called stomata. Through these pores, plants take in gases for respiration and photosynthesis. The gases produced during these processes are also given out through stomata. (3) The plants give out extra amount of water in the plant through stomata, in the form of vapours. This process is known as transpiration. (4) In addition, leaves may be variably modified into spines or tendrils or modified to trap insects.  The largest leaf is present in Giant, Water lilly, Victoria regia, more than 1metre in diameter.  Flowering plant with no leaf-Dodder (Cuscuta).  All leaves are not green. Some leaves have patches of white or yellow or red colour. Such leaves are called variegated leaves.  Plants with variegated leaves – Money plant (Coleus). TYPES OF LEAVES (i) Simple and Compound leaves: Try to examine the leaves of mango and neem trees. In a mango leaf, the lamina is entire whereas in a neem plant, the leaf lamina is cut into small parts, called leaflets, on a common stalk. The leaf with a single lamina, as in mango, castor, cotton, china-rose, is called a simple leaf (Figure. 5.12). A simple leaf has an axillary bud. The leaf in which the lamina is cut into a number of small leaflets on a common stalk is called a compound leaf (Figure. 5.13). Rose, neem, tamarind show compound leaves. Leaflets do not bear axillary buds. The stalk of a compound leaf is called rachis which has an axillary bud.

Figure 5.12: A simple leaf

Figure 5.13: A compound leaf

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Structure and Functions of plant parts

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VENATION Venation found in the leaves is of two types. (i) Reticulate and (ii) Parallel. Reticulate venation: When the veins in the leaf lamina divide repeatedly forming a network, it is called reticulate venation (Figure. 5.14). Examples: Dicotyledonous plants like mango, peepal show this type of venation. Parallel venation: When the veins run parallel to each other from the base to the tip of the laminao, it is called parallel venation (Figure. 5.15). Examples: Monocotyledonous plants like banana, wheat, palms.

Figure 5.14: Reticulate venation

Figure 5.15: Parallel venation

ARRANGEMENT OF LEAVES The leaves are arranged in various ways on the stem. The arrangement of leaves on the stem is called phyllotaxy. The main aim of phyllotaxy is to expose all the leaves of the plant to maximum sunlight and air. Three types of leaf arrangement (Figure. 5.16) are commonly noticed in plants. These are: (i) Alternate : A single leaf arises at each node and on opposite side of the previous leaf. Examples : Mango, sunflower. (ii) Opposite : Two leaves arise at each node apposite to each other. Examples : Calotropis, guava. (iii) Whorled : More than two leaves arise at each node, and are arranged in a whorl or circle. Examples : Oleander, asparagus.

Figure 5.16: Arrangement of leaves MODIFICATIONS OF LEAF (a) In xerophytic plants like cacti, opuntia, the leaves are modified into spines (Figure. 5.17). These spines check the loss of water from the plant body and, thus, help the plant to conserve water. (b) In sweet pea and pea, some leaves are modified into thin, coiled thread-like tendrils. These help the plant in climbing.

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6th Biology

61 (c) (d)

In onion, the fleshy leaves store food material. In some plants, the leaves are modified to trap insects. Such plants are called insectivorous plants. Examples—Pitcher plant (Figure. 5.18), sundew plant and bladder wort.

Figure 5.17: Leaf tendril in garden pea

Figure 5.18: Pitcher plant – the leaf modified into a pitcher

6. THE FLOWER Flower is the main reproductive organ of a plant. STRUCTURE OF A FLOWER Observation: Let us examine a flower of gulmohr to know about the structure of a flower. The flower has a fairly long stalk. This stalk is called pedicel. Other floral parts arise at the end of the stalk. There are five triangular, green structures. They are slightly coloured on the inner side. They are the sepals and form a whorl.

Figure 5.20: Flower of Gulmohr Observe a floral bud (figure. 5.20 A). In the next whorl, we find outer leafy structures of the bud are the sepals of the flower (figure 5.20 C).

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Structure and Functions of plant parts

62

Next to the sepals are five brightly coloured petals (figure 5.20 D). They are the most conspicuous part of the flower and make it attractive. In next whorl, we find long filaments. Each filament is a part of a stamen (figure 5.20 E). It has a distinct tip with two anthers. Split open an anther. We find fine yellow particles in the anther. These are the pollen grains. In the next whorl, we find a single elongated structure in the centre of the flower. It is broader below and tapers at the top. This is the pistil or carpel (figure 5.20 F). The lower broader part is the ovary. Its slender elongated part is the style. The end of the style which is sticky is the stigma. In longitudinal section of ovary, we find whitish structures (figure 5.20 G). These are the ovules. The ovules are attached to the margin of the ovary (figure 5.20 H). Gulmohr has both male (stamens) and female (pistil) parts of the flower. It is, therefore, a bisexual flower. Note: All plants do not have flowers with both stamens and carpels. Some have only stamens and are the male flowers. Some have only pistil, and are the female flowers. Such flowers are called unisexual flowers. Examples: Cucumber and gourd. Conclusions: A flower represents the reproductive part of a plant body. It is, the most important part meant for multiplication of the species. Often, each flower has a stalk called the pedicel. But some flowers do lack the pedicel, and such flowers are called sessile. Besides the stalk, a flower, in general, shows four sets of whorls or parts arranged in rings or whorls (Figure. 5.21).

Figure 5.21: Parts of a Flower Calyx is the outermost whorl or set composed of green, leaf-like protective structures called sepals. 2. Corolla is the next inner whorl composed of brightly coloured petals. Being brightly coloured, petals attract insects for pollination. 3. Stamens are next to corolla and consist of anthers and filaments. Anthers are swollen structures present on the tip of filaments. The anthers produce a powdery substance consisting of tiny structures called the pollen grains. The stamens represent the male part of a flower. Male sex cells are produced inside the pollen grains. 4. The central part of the flower is the female part, consisting of a flask-shaped organ, called the carpel. Each carpel consists of a basal swollen part called the ovary. The ovary continues into a long style and ends in a knob-like part, called the stigma. The ovary contains many ovules. Female sex cell is present inside the ovule. Ovules and ovary finally develop into seeds and fruits respectively. Largest flower – Rafflesia grows in Indonesia ; nearly 1 metre in dameter. Smallest flower – Duckweed (Wolffia); only about 0.5 millimetre in diameter. 1.

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6th Biology

63

TYPES OF FLOWERS Based on the presence of whorls, flowers can also be classified as follows: Complete flower: A flower consisting of all the four whorls-calyx, corolla, stamens and carpels is called a complete flower. Examples: mustard, china-rose and pea. Incomplete flower: In some flowers, one or more whorls may be missing. Such flowers are called Incomplete flowers. Examples: date palm and mulberry. FUNCTIONS OF A FLOWER 1. Role in reproduction and multiplication: Flower is the most important part of a plant i.e., it takes part in reproduction and leads to the formation of seeds and fruits. Seeds on germination produce new plants. 2. Ornamental value: Flowering plants are grown in gardens and in homes because of their bright colours and fragrance. 3. Source of food : Nectar from flowers serves as a food for insects.

Formative Worksheet 23.

The given figure illustrates the structure of a leaf. What is label X in the given figure? (A) Petiole (B) Lamina (C) Midrib (D) Vein

24.

Which of the following functions is not performed by roots? (A) Storage of food (B) Preparation of food (C) Absorption of water (D) Anchorage of plant Simple leaf is present in (A) Mango (B) Castor (C) Cotton (D) All The arrangement of veins on the leaf lamina is called (A) Phylotaxy (B) Venation (C) Inflorescence (D) All Plants that have parallel venation in their leaves are i and ii . The information in which alternative completes the given statement? (A) i- wheat ii- rice (B) i- rice ii- tulsi (C) i- tulsi ii- mint (D) i- mint ii- wheat Match the following Column-I (phyllotaxy) Column-II (Example) 1) Alternate p) oleander 2) Opposite q) calotropis 3) Whorled r) mango (A) 123/rpq (B) 123/qpr (C) 123/prq (D) 123/qrp In which of the following plants, the leaf is modified to trap the insects? (A) Pitcher plant (B) Sundew plant (C) Bladder plant (D) All Which part of a plant is its reproductive part? (A) Stem (B) Roots (C) Leaves (D) Flower ____i_____ and ____ii_____ are plants which have unisexual flowers. The information in which alternative completes the given statement? (A) i- Corn ii- cucumber (B) i- Cucumber ii- mustard (C) i- Mustard ii- rose (D) i- Rose ii- corn Unisexual flowers are a type of flowers which contain either _____i_____ or ____ii_____. The information in which alternative completes the given statement? (A) i- stamens ii- pistil (B) i- pistil ii- petals (C) i- petals ii- sepals (D) i- sepals ii- stamens

25. 26. 27.

28.

29. 30. 31.

32.

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Structure and Functions of plant parts

64

33.

Which of the following statements about bisexual flowers is correct? (A) They do not contain stamen and pistil. (B) They contain both stamen and pistil. (C) They contain only stamen. (D) They contain only pistil. 34. Which alternative correctly matches the parts of a plant and the method of (A) Method of Plant parts (B) Method of reproduction

(C)

reproduction? Plant parts

reproduction

Asexual

Stem, leaves, roots

Asexual

Flowers, seeds

Sexual

Flowers, seeds

Sexual

Stem, leaves, roots

Method of reproduction

Plant parts

Method of reproduction

Plant parts

Asexual

Stem, flowers

Asexual

Seeds, leaves, roots

Sexual

Seeds, leaves, roots

Sexual

Stem, flowers

(D)

35.

Andy drew a flower in his drawing notebook. Which part of the flower did he forget to draw? (A) Pistil (B) Petals (C) Sepals (D) Stamen

36.

The main function of petals is to (A) Produce eggs (B) Produce pollens (C) Attract insects for pollination (D) Capture light for photosynthesis Which of the following parts of a flower is not a component of carpel? (A) Stigma (B) Ovary (C) Style (D) Filament Which part of flower produces pollens? (A) Filament (B) Anther (C) Ovary (D) Style ____i____ and ____ii____ are parts of the stamen. The information in which alternative completes the given statement? (A) i-filament ii-anther (B) i-anther ii- style (C) i-style ii-stigma (D) i-stigma ii-filament The given illustration represents the pistil of a flower. Label X in the illustration represents (A) Stigma (B) Ovary (C) Style (D) Ovule

37. 38. 39.

40.

41.

42.

The plant structures particularly responsible for sexual reproduction are the ___I___ and the ___II____. Which row correctly completes the given statement? (A) i- petals ii- sepals (B) i- pedicel ii- stalk (C) i- stamen ii- carpel (D) i- leaves ii- roots The part of flower that has a sticky surface and performs the function of receiving pollen grains is called (A) Stigma (B) Anther (C) Petals (D) Ovary

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6th Biology

65 43.

The labels X and Y in the given figure respectively represent the (A) Sepal and the stamen (B) Stamen and the pistil (C) Pistil and the petal (D) Petal and the sepal

44.

Flower is the reproductive organ of a plant which produces pollen and ovules. Ovules are formed in the (A) Pistil (B) Petal (C) Sepal (D) Stamen A flower contains four parts that perform different functions. In a flower, eggs are produced in the (A) Stamen (B) Pistil (C) Sepal (D) Corolla The flower in which all four whorls are present is called (A) Complete flower (B) Incomplete flower (C) Both (D) None Which of the following functions is carried out by flowers? (A) Production of food (B) Production of seeds (C) Absorption of sunlight (D) Transportation of nutrients

45.

46. 47.

Conceptive Worksheet 19.

20.

21.

The given diagram illustrates a peepal leaf. The structure labelled I in the given diagram represents the (A) Petiole (B) Lamina (C) Petals (D) Sepals Which of the following is true? (I) The manufacture food for the plant body (II) They aid in exchange of gases for respiration and photosynthesis (III) They give mechanical support to the plant body (IV) They help in reproduction (A) I, II (B) II, III (C) III, IV (D) I, IV Soha plucks a leaf of wheat plant. The venation she observes in this leaf is similar to which of the following kinds of leaf? (A) (B)

(C)

22. 23.

(D)

Plants have special parts that help them to reproduce. The reproductive part of a plant is in its (A) Flower (B) Stem (C) Root (D) None A flower that has both stamen and pistil is known as i flower. The example includes rose and ii . The information in which alternative completes the given statements? (A) i- unisexual ii- cucumber (B) i- bisexual ii- cucumber (C) i- unisexual ii- mustard (D) i- bisexual ii- mustard

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Structure and Functions of plant parts 24.

Which of the given figures represents a unisexual flower? (A) (B)

(C)

25.

26.

66

(D)

A unisexual flower contains either ____i____ or ____ii_____. The information in which alternative completes the given statement? (A) i-sepals ii-petals (B) i-petals ii-pistil (C) i-pistil ii-stamens (D) i-stamens ii-sepals The structures marked I and II in the given figure represent (A) Sepals and pistil (B) Stamen and pistil (C) Sepals and petals (D) Stamen and petals

27.

The given diagram shows all floral parts. During reproduction, the main function of the part labeled IV is to (A) Produce eggs (B) Produce pollens (C) Take part in fertilization (D) Attract insects towards flowers

28.

The given illustration represents the stamen of a flower. Label X in the illustration represents (A) Filament (B) Style (C) Carpel (D) Anther Peter gave a flower to his kid sister. She immediately noticed that a particular part of the flower was missing. Which part of the flower was missing? (A) Stamen (B) Sepals (C) Petals (D) Pistil The given illustration represents a flower. In the given illustration, the stamen is labelled as (A) I (B) II (C) III (D) IV

29.

30.

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6th Biology

67 31.

32.

33.

34. 35.

36.

37.

38.

Madison dissected the flower illustrated in the given figure. After the dissection, she makes certain observations. Some of these observations are as follows: I. The flower has six sepals. II. The flower has petals. III. The flower has one pistil. IV. The flower has six stamens. Which of the following observations made by Madison is incorrect? (A) I (B) II (C) III (D) IV The main function of the stamen is to (A) Produce pollens (B) Produce eggs (C) Protect seeds (D) Protect buds Which function will not be performed by the flower shown in the given figure? (A) Production of pollens (B) Production of eggs (C) Fertilization (D) Pollination Pollen grains are produced in (A) Anther (B) Filament (C) Ovule The given illustration represents the pistil of a flower. Label X in the illustration represents (A) Style (B) Stigma (C) Ovary (D) Ovule

(D) Stigma

Carpel is composed of (A) Style, stamen, and ovary (B) Stigma, style, and ovary (C) Stamen, anther, and ovary (D) Stigma, stamen, and ovary The given figure shows a dissected flower viewed with a magnifying glass. The number of ovules present in the given figure is (A) 1 (B) 2 (C) 5 (D) 6 Stigma helps in (A) The formation of pollen grains (C) Attracting bees and birds

(B) The protection of flower buds (D) Receiving pollen grains

7. SEXUAL REPRODUCTION In nature, sexual reproduction occurs in plants as well as in animals. It is the most common method of reproduction. A flower is the seat of sexual reproduction in plants. Two parents, one male, and the other female, are required for sexual reproduction. Two types of sex or reproductive cells, called gametes are produced from the reproductive organs of two parents. Male parent produces the male gametes and the female parent produces the female gametes. The stamens produce pollen grains which contain the male gametes. The female gamete is a large egg-cell produced inside the ovule. A male gamete is usually small with a nucleus and little cytoplasm. The female gamete is larger, with a nucleus and more cytoplasm than the male. The fusion of the two gametes is called fertilization. The product of fusion of the two gametes is called the zygote. After fertilization, the zygote undergoes cell division and growth. Ultimately, it forms the new individual.

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8. POLLINATION Pollination is the transfer of pollen grains from the ripe anther to the stigma. The transfer of pollen grains to the stigma can take place in two ways: (i) Within the same flower or between flowers of the same plant. (OR) (ii) Between flowers from different plants of the same species. Pollination in the first case is called self pollination, while it is called cross pollination in the second case(Figure. 5.22). Cross pollination often involves various external agencies to carry pollen grains from one flower to another one. These agencies may be air, water or insects. Most flowers are pollinated by insects. Pollen grains of all flowers are not carried by insects. In some cases, they are carried by wind (wind pollination). In case of water plants, pollen grains are carried by water (water pollination). Figure 5.22: Self and Cross pollination

1. 2. 3. 4.

Table 5.2: Difference between Insect-pollinated and Wind-pollinated flowers Insect-pollinated flowers Wind-pollinated flowers Large and brightly-coloured 1. Small and inconspicuous. Nectar and scent is produced. 2. No nectar or scent is produced. Pollen grains are sticky. 3. Pollen grains are dry. Pollen grains are produced in less quantity. 4. Pollen grains are produced in large quantity.

9. FERTILIZATION Fertilization is a step between pollination and seed formation. The fusion of the male gamete with the female gamete is called fertilization. During fertilization, the following events take place: 1. The pollen grains germinate on the stigma, and pollen tubes develop. 2. The pollen tubes move downwards into the style (Figure. 5.23). 3. The pollen tubes are the carriers of male gametes.

Figure 5.23: Pollen grain develops into a pollen tube carrying male gametes

Figure 5.24: Female gamete (egg cell) inside the ovule

Figure 5.25: Process of fertilization

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2.

One pollen tube finally enters the ovule, where female gamete (egg) is located (figure 5.24, 5.25) Female gamete or egg cell is present inside the ovule. Finally the male gamete fuses with the female gamete. This completes the process of fertilization.

3.

10. FORMATION OF FRUIT AND SEED FORMATION OF FRUIT AND SEED 1. The flower loses its bright colour. 2. The sepals, petals and stamens fall off. 3. The ovary increases in size and becomes the fruit. 4. The ovary wall becomes the fruit wall. 5. Inside the ovary, the ovules develop to form the seeds. TYPES OF FRUITS (i) Dry fruit: Fruits of the type of pea are called dry fruits. The fruit wall in such a fruit is thin and dry. Examples: Cotton, lady’s finger, maize, sunflower, bean. (ii) Fleshy fruit: On the other hand, mango fruit is a fleshy fruit, as the fruit wall is thick and fleshy. Examples: Tomato, brinjal, orange, coconut, plum. FUNCTIONS OF FRUITS (i) The fruit wall gives protection to the seeds and therefore to the embryo. (ii) The fruit is a store house of food material. (iii) The fruit helps in dispersal of seeds. SEED A seed contains an embryo, one or two cotyledons and a protective seed coat (Figure. 5.26). The embryo, after germination of the seed, develops into a new plant. The cotyledons often contain reserve food material for the developing plant.

Figure 5.26: Structure of gram seed 11. STRUCTURE OF A FRUIT A fruit is a ripened ovary formed after fertilization. A fruit, consists of two parts (i) The fruit wall (or pericarp), and (ii) Seeds. FRUIT WALL The fruit wall develops from the wall of the ovary. It may be thick or thin. It may be dry as in pea or gram (Figure. 5.26) or fleshy as in tomato (Figure. 5.27) and papaya. In fruits like mango, the pericarp may be differentiated into three layers (Figure. 5.28): The fruit wall has three layers: 1. the outer layer called the epicarp, 2. the middle layer called the mesocarp, and 3. the inner layer called the endocarp.

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Structure and Functions of plant parts

Figure 5.27: Parts of a Fruit (Tomato)

70

Figure 5.28: Parts of a fruit (mango)

SEEDS Seeds which develop from the ovules are present inside the fruit wall. A fruit may contain only one seed (as in mango, plum) or many seeds, as in the case in tomato, orange, apple. Fruits of the type of pea are called dry fruits. The fruit wall in such a fruit is thin and dry. On the other hand, mango fruit is a fleshy fruit, as the fruit wall is thick and fleshy FUNCTIONS OF A FRUIT 1. It protects the seeds from animals and unfavourable climatic conditions. 2. It helps in dispersal of seeds to distant places by means of various devices which the fruits often develop. 12. THE SEED A seed contains a baby plant inside. It also contains food for the new plant to develop. More precisely, seed consists of an embryo, one or two cotyledons and a protective seed coat. Embryo is represented by plumule and radicle (Figure. 5.29). The cotyledons often contain the reserve food material for the developing plant. On germination, plumule gives rise to the shoot system while radicle gives rise to the root system (Figure. 5.30) and thus, develops a new plant.

Figure 5.29: Parts of a seed – The two cotyledons slightly separated showing the embryo plant between them

Figure 5.30: Seed Germination

13. DISPERSAL OF SEEDS AND FRUITS Plant do not move. The seeds and fruits produced by them have developed devices which help them to be carried to faraway places. This prevents overcrowding at one place and also leads to the spread of plants to newer places. There are three main types of dispersal mechanism: (i) By Wind (ii) By Water (iii) By Animals DISPERSAL BY WIND Examine the seeds of dandelion, Calotropis (madar), Acer (maple), cotton and pine. Seeds of dandelion (Figure. 5.31) and cotton possess a tuft of fine hair, while in Acer and pine (Figure. 5.32), the fruits/seeds develop flat, wing-like structures.

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Figure 5.31: Dandelion Figure 5.32: Winged fruit of Acer The hair or the wings help in the dispersal of seeds and fruits to long distances by wind. DISPERSAL BY WATER Coconut plants are grown on the sea shore. The fibrous fruit falls in water and is carried away from the parent plant by water currents. In lotus, the fruit floats on the surface of water and the seeds are liberated in water. Water currents carry the seeds to long distances. DISPERSAL BY ANIMALS Seeds and fruits dispersed by animals are either edible or develop hooks and thorns. Seeds of fruits like mango, orange and plum get dispersed after the fleshy part of these fruits is eaten by humans and birds. Fruits of gokhru (Tribulus) and okra (Xanthium) possess hooks and spines (Figure. 5.33). These fruits stick to our clothes and to the body of passing animals, and then get carried away from one place to another. This, plants have developed various means to get their seeds and fruits carried away to long Figure 5.33: Fruit of Xanthium with spines distances.

Formative Worksheet 48. 49. 50. 51.

52.

53. 54.

55.

The male reproductive part of a flower is known as the (A) Stamen (B) Pistil (C) Petal (D) Sepal Female gametes or eggs are produced in the (A) Anther (B) Filament (C) Ovary (D) Style Which of the following parts of the flower is the male reproductive part? (A) Stamen (B) Pistil (C) Petal (D) Sepal Which of the following parts of the flower aid in the sexual reproduction? (A) Stamen and petals (B) Petals and sepals (C) Sepals and pistils (D) Ovaries and Stamens Flowers are the reproductive organs of plants. Pollination occurs when pollens are transferred within a flower or from one flower to another. Pollination is the transfer of pollens from (A) Stigma to anther (B) Petals to sepals (C) Anther to stigma (D) Sepals to petals Cross pollination occurs through the agents like (A) Air (B) Water (C) Insects (D) All In plants, fruits are formed by the fertilization of ovary. Fruits help plants in (A) Producing food (B) Producing oxygen (C) Protecting the seeds (D) Protecting the leaves A particular part of flower performs the function of producing eggs. On fertilization, these eggs develop into seeds. Which part of flower performs the described function? (A) Filament (B) Stigma (C) Anther (D) Ovary

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Structure and Functions of plant parts 56.

57.

58. 59.

60. 61.

62. 63. 64. 65.

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Which of the following statements regarding fruits is correct? (A) Fruits are always covered by a protective covering. (B) Fruits develop from the ovary after fertilization. (C) Fruits are always present inside the seeds. (D) Fruits are always fleshy. The plant part shown in the given figure performs the function of (A) Protection of seeds (B) Protection of roots (C) Photosynthesis (D) Respiration Which of the following parts of a plant produces seeds? (A) Stems (B) Roots (C) Leaves (D) Flowers Which of the following numbers represents the number of seeds found inside the fruit that develops from an ovary containing 16 ovules? (A) 8 (B) 16 (C) 32 (D) 64 The seeds produced by flowers give rise to new plants. Seeds are produced inside the (A) Anther (B) Stigma (C) Ovary (D) Petal In the given figure, the structure labelled i develops into ii while the structure labelled iii develops into iv after fertilisation. The information in which alternative completes the given statement? (A) i-I ii-fruit iii-iv iv-seed (B) i-III ii-seed iii-II iv-fruit (C) i-II ii-seed iii-III iv-fruit (D) i-III ii-fruit iii-IV iv-seed The fruit wall develops from (A) Sepal (B) Petal (C) Stamen Which of the following part of a seed gives rise to shoot system? (A) Seed code (B) Plumule (C) Radicle In which of the following, the seeds are dispersed by wind? (A) Calotropis (B) Acer (C) Cotton The fruits of coconut are dispersed by (A) Wind (B) Water (C) Animals

(D) Ovary (D) Embryo (D) All (D) All

Conceptive Worksheet 39.

The given figure illustrates the section of a flower. In the given figure, which two labelled parts perform the same type of function? (A) I and II (B) II and III (C) I and IV (D) III and IV

40.

The part of a flower that produces eggs is the (A) Sepal (B) Petal (C) Pistil Statement-I: Insect pollinated flowers are large and brightly coloured. Statement-II: In wind pollinated flowers, the pollen grains are dry. (A) Statement-I is true, Statement-II is false (B) Statement-I is false, Statement-II is true (C) Both statements are true (D) Both statements are false

41.

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(D) Stamen

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42.

Statement-I: Pollen grains of all flowers are carried only by insects Statement-II: The wind pollinated flower are large and brightly coloured (A) Statement-I is true, Statement-II is false (B) Statement-I is false, Statement-II is true (C) Both statements are true (D) Both statements are false 43. After the process of fertilization, fruits are formed. These fruits contain seeds. Which structure gives rise to fruits? (A) Ovule (B) Ovary (C) Stigma (D) Style 44. The given figure shows a unisexual flower. Which statement about the given flower holds true? (A) It can perform photosynthesis (B) It can perform transpiration (C) It cannot produce pollens (D) It cannot produce eggs 45. The fruits of a plant are developed from (A) Anthers (B) Sepals (C) Petals (D) Ovary 46. Fruits develop from the ripened _____i_____ while the seeds develop from the ___ii______. The information in which alternative completes the given statement? (A) i-ovary ii-ovules (B) i-ovules ii-stigma (C) i-stigma ii-style (D) i-style ii-ovary 47. Statement-I: Cotton is a dry fruit Statement-II: Coconut is a dry fruit (A) Statement-I is true, Statement-II is false (B) Statement-I is false, Statement-II is true (C) Both statements are true (D) Both statements are false 48. Pollens are produced inside (A) Ovary (B) Anther (C) Stigma (D) Filament 49. The seed of a plant contains an embryo that grows into a new plant. The seed of a plant is formed from the (A) Matured fruit (B) Ripened ovule (C) Matured flower (D) Ripened flower 50. Which part of the pistil develops into a seed after fertilization? (A) Ovary (B) Ovule (C) Style (D) Stigma 51. Seeds are formed from the (A) Ripened ovules (B) Ripened anthers (C) Modified roots (D) Modified stems 52. Different parts of a pistil help in the formation of fruits and seeds after fertilization. Which of the following statements regarding seeds is incorrect? (A) Seeds are ripened ovaries. (B) Seeds contain the embryo. (C) Seeds are present inside the fruit. (D) Seeds have a protective seed coat. 53. Statement-I: The outer layer of fruit wall is called Statement-II: Fruit protect the seeds from animals and unfavourable conditions (A) Statement-I is true, Statement-II is false (B) Statement-I is false, Statement-II is true (C) Both statements are true (D) Both statements are false 54. Statement-I: In mango and orange, the seeds are dispersed by water Statement-II: In Tribulus and Xanthium, the fruits are dispersed by animals (A) Statement-I is true, Statement-II is false (B) Statement-I is false, Statement-II is true (C) Both statements are true (D) Both statements are false SNAP SHOT 1. Multicellular organisms show a definite organisation of cells into tissues, organs, organ-systems and finally the organism. 2. A flowering plant consists of two parts - the root system and the shoot system. 3. The root system consists of the roots which may be of two types - tap root and fibrous root. 4. The shoot system consists of stem, leaves, flowers and fruits.

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Structure and Functions of plant parts 5. 6. 7. 8. 9.

10. 11.

12.

13.

14. 15.

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Roots, stem and leaves constitute the vegetative parts of the plant while flowers and fruits are the reproductive parts. Roots perform several functions - fix the plant to the ground, absorb water and minerals from the soil, and also bind the soil particles together. In some plants, roots are modified to perform additional functions of storage (carrot, turnip), support (banyan) or respiration (Rhizophora). The stem is divided into nodes and internodes and bears apical buds and axillary buds. The stem provides support, helps in conduction of water and minerals and photosynthesis, and in some cases it is modified to perform the additional function of storage (potato, ginger), support (grapevine) and photosynthesis (cactus). The leaf is a green flattened structure, meant for manufacturing food for the plant body by the process of photosynthesis. A leaf, typically, consists of three parts - leaf base, stalk or petiole and leaf blade or lamina. Besides performing the function of photosynthesis, leaves also carry out respiration and transpiration. In some cases, leaves are modified into spines or tendrils or modified to trap insects. The reproductive part, flower, consists of four sets of floral parts, arranged in whorls. These are calyx, corolla, stamens and carpels. Stamens represent the male reproductive organs, while carpel is the female reproductive organ. Male gamete is produced by pollen grains inside the anthers. Female gamete is present indide the ovule of an ovary. Transfer of pollen grains from the ripe anthers to the stigma is called pollination. Pollination within the same flower or between flowers of the same plant is called self pollination. Pollination that occurs between flowers from different plants of the same species is called cross pollination. Pollination is followed by fertilisation, which is the fusion of the male cell with the egg cell. Fertilization results in the formation of fruits and seeds. A fruit is a ripened ovary. It consists of (i) a wall called pericarp, and (ii) seeds. Dispersal of seeds and fruits may be brought about by wind, water or animals.

Summative Worksheet I. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.

Multiple choice questions. Which of the following has a tap root? (A) Maize (B) Wheat Which of the following possesses fibrous roots? (A) Balsam (B) Wheat Which of the following is a modified root? (A) Potato (B) Onion Which of the following is a modified stem? (A) Radish (B) Sweet potato Which of the following is a modified leaf? (A) Spines of cactus (B) Maize Banyan plant possesses (A) Supporting roots (B) Stem tendrils Veins are present in (A) Stems (B) Roots Pollen grains are produced in (A) Flowers (B) Ovaries Seeds are produced from the (A) Ovules (B) Ovary The pistil consists of (A) Anthers and filaments (C) Ovary, ovule, female gamete

(C) Pea

(D) Rice

(C) Marigold

(D) Tulsi

(C) Ginger

(D) Turnip

(C) Beet

(D) Turmeric

(C) Sugarcane

(D) Banyan

(C) Modified leaves

(D)Storage roots

(C) leaves

(D) seeds

(C) Anthers

(D) Fruits

(C) Stigma

(D)Pollen grains

(B) Style, stigma, ovary (D) Ovary, stigma, anther

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II. 1. 2. 3. 4. 5. 6. 7.

Fill in the blanks: A plant showing tap root is ________________. . An example of a plant with fibrous roots is ________________. Ginger is a modified________________. Onion is a modified ________________. In cactus, leaves are modified into ________________. Leaves are green as they contain ________________. In addition to a tap root, a banyan plant possesses roots arising from branches. These roots are meant for ________________. The vegetables such as carrot and radish that you eat are modified ________________. In pitcher plant, ________________ are modified for trapping insects. In the shoot system, leaves arise from ________________ on the stem. Plants synthesize food by the process of ________________ The root system arises from ________________in the embryo. Tiny pores present on the leaf surface are called ________________. The four whorls of a flower are ________________ and ________________. Pollen grain is produced in ________________. Ovules grow into ________________ and ovaries into ________________ after fertilisation. ________________ is the male reproductive organ of a flower. The transference of pollen grains from the anther to the stigma is called ________________. The ovary contains ________________. During germination, plumule gives rise to the ________________ and radicle gives rise to the ________________. Which of the following statements are true (T) and which ones are false (F)? Mark T or F Statements T/F 1. The sugarcane plant has fibrous roots. __________ 2. Sweet potato is a stem. __________ 3. Potato is a root. __________ 4. Leaves are reduced to spines in a cactus plant. __________ 5. Most flowers have colourful sepals. __________ 6. Internode is the leafless portion of stem. __________ 7. Shoot system consists of stem and its branches, leaves, flowers and fruits. __________ 8. Roots absorb water and minerals from the soil. __________ 9. The wheat plant has fibrous root system. __________ 10. Plants can carry out photosynthesis without carbon dioxide. __________ 11. Stamens make egg cells. __________ 12. A fertilized egg becomes a seed. __________ 13. Insect-pollinated flowers are brightly coloured. __________ 14. Wind-pollinated flowers produce pollen grains in large quantity. __________ Match the items in Column A with those in Column B : Column A Column B (a) Tap root (i) Support (b) Fibrous root (ii) Leaf (c) Tuberous root (iii) Flower (d) Supporting root (iv) Grape vine (e) Breathing roots (v) Mango (f) Rhizome (vi) Respiration (g) Stem tendril (vii) Maize (h) Leaf modification (viii) Ginger (i) Stomata (ix) Storage (j) Stamen (x) Pitcher plant Define the following terms: 1. Tissues 2. Organs 3. Venation 4. Gamete 5. Pollination 6. Fertilization 7. Zygote 8. Fruit 9. Regeneration 10. Seed

8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. III.

IV.

V.

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VI.

Find the odd one out, giving reasons. 1. Root, stem, flowers, leaves. 2. Tuber, bulb, rhizome, tendrils. 3. Petals, sepals, anthers, root. 4. Cross pollination, self pollination, wind pollination, water pollination. 5. Style, ovary stigma, filament. VII. Give the differences between the following: 1. Root and Stem 2. Node and Internode 3. Simple and Compound leaves 4. Seed and Fruit 5. Reticulate and Parallel venation 6. Self pollination and Cross pollination VIII. Answer the following questions: 1. Mention the two main systems found in plants. 2. Describe the root systems found in plants. Give examples. 3. What are the functions of roots? 4. Why certain plant parts are modified? 5. (a) Mention any two modifications found in roots. Give examples with diagrams. (b) Name two plants having supporting roots. 6. What are the main functions of the shoot? (a) Which plant organs are modified for storage of food in a potato and an onion? (b) Name the stem medifications found in potato, ginger and onion. 7. Name some modified roots and stems, which are eaten by man. 8. Describe the modifications found in a cactus plant. 9. Why is the stem of a cactus plant thick and green? What is the role of spines? 10. Give one example of a plant with stem tendrils. 11. Name two insectivorous plants. Which part of the plant body is modified in these plants? 12. Mention three functions of leaves. 13. With the help of diagrams, describe the structure of a leaf and a carpel. 14. Describe the different parts of a complete flower. 15. What part is played by stamens and carpels in reproduction? 16. In which part of the flower is the ovule found? 17. Name the three agents of pollination. 18. Where does fertilization occur in a flowering plant? 19. Describe the parts of a fruit. Draw a well-labelled diagram in support of your answer. 10. Outline the structure of a seed. Name its parts. IX. Here is the picture of a plant. Study the picture and answer the following questions: 1. Write the names of the different parts of the plant. 2. Which plant organ holds up the leaves and flowers? 3. Which plant organ makes food? 4. Which plant organ is needed for reproduction? 5. Which plant organ carries water to the leaves?

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By the end of this chapter, you will understand  Know about the sources and roles of different nutrients in food  Understand the characteristics of good health and the factors which help to maintain good health  Understand the significance of balanced diet  Take care of your teeth, eyes and hair  Take care of your own hygiene (personal hygiene)  Know about the community hygiene  Know about disposal and treatment of wastes  Learn the methods of purifying water  Know about the effects of pollution on health  Understand transmission, prevention and control of communicable diseases  Learn about the first aid methods in case of burns, bruises and cuts

HEALTH AND HYGIENE

Chapter -6

Learning Outcomes

1. INTRODUCTION Very often you would have heard your grandparents telling you that 'health is wealth'. This saying in very simple words highlights the importance of health. Health, in a broad sense of the word, is a state of well-being, and not merely the absence of a disease. A person may not be suffering from any disease, and yet one may not feel completely well. We call a person healthy if he enjoys good health most of the time. The World Health Organisation (WHO) has defined health as a "state of complete physical, mental and social well-being." Good health makes us happy and cheerful. It enables us to lead a happy life. Health is often upset by diseases. A disease or illness occurs when the body or any of its parts is not working correctly. Any disturbance in the working of the body produces a disease. A disease is, thus, opposite to health. Diseases may be due to (i) imbalances in the diet, or (ii) due to infection by microorganisms. 2. FOOD FOR HEALTH Food is essential for our body. We cannot survive without food. Food is required by the body for the following purposes: 1. For energy required to perform various functions to sustain life. 2. For growth;. Without proper food, your growth would not be possible. 3. For repair of damaged or injured body parts; when you get hurt, you damage the skin and the blood is lost. Repairs of such damaged parts takes place by addition of new cells. 4. For protection from diseases and infection. NUTRIENTS IN FOOD There are six essential constituents called nutrients in our food. These are: 1. Carbohydrates 2. Fats 3. Proteins 4. Mineral salts 5. Vitamins 6. Water In addition, roughage (fibre) is another important dietary constituent, which is required to prevent constipation. It is not enough that all these components are present in the diet. Ideally, our food should contain sufficient (i) energy-giving foods (like carbohydrates and fats), (ii) body-building or growth-promoting foods (like proteins), and (iii) protective foods (vitamins and minerals).

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Foods, thus, on the basis of their role in the body, are classified into three groups as energy-giving, body-building and protective foods. Carbohydrates  These are the common energy-giving compounds, and include sugars, starches and cellulose.  Foods rich in carbohydrates are potato, sweet potato, bread, rice, wheat, honey, common sugar, jaggery (gur) and milk. Fats  These are also energy-giving foods, producing more energy than carbohydrates.  Fat-rich foods are (i) milk products such as butter and cheese, (ii) vegetables oils such as coconut oil, groundnut oil, (iii) nuts, (iv) milk and (v) animal fat from meat. Proteins  These are body-building foods.  Proteins help the body in its growth, and repair of body cells and tissues.  They also protect and help the body to fight infections and regulate body functions.  Protein sources of plant origin include pulses (soyabean, peas) and to a lesser extent cereals. Meat, eggs, cheese, milk and fish provide proteins of animal origin. Mineral salts  Mineral salts are important for various body functions. They are required in small quantities and are obtained from the food we take in.  Minerals have no energy value.  Salts of calcium and phosphorus are required for making bones and teeth hard and for promoting clotting in our body.  Rich sources are milk, cheese, green leafy vegetables like spinach, pulses, meat and eggs.  Iron is essential for forming haemoglobin, a component of our blood, the deficiency of which causes anaemia.  Green leafy vegetables, eggs, groundnuts, and liver are good sources of iron.  Iodine, another mineral, controls the functioning of an important gland, thyroid.  Deficiency of iodine leads to goitre. Iodised salt, fish and seafood are the sources of this mineral. Vitamins :  These are very important for proper functioning of our bodies.  Vitamin-deficiency leads to diseases.  They are required by the body in very small quantities.  Green leafy vegetables, fruits, milk, eggs and cheese are rich in vitamins Water :  Water is indispensable. About 70 per cent of our body weight is that of water.  It helps the body in various functions. It is a means of transporting substances in the organism.  It helps to maintain a constant body temperature.  Water helps in the absorption of food and excretion of waste products from the body.

Formative Worksheet 1. 2.

Roughage (fibre) is another important dietary constituent, which is required to prevent (A) Diabetes (B) Constipation (C) Malaria (D) Typhoid The body-building or growth-promoting foods contain (A) Carbohydrates (B) Proteins (C) Vitamins (D) Minerals

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79 3.

4.

5.

6.

7.

8. 9. 10. 11. 12.

Statement-I: Carbohydrates provides us energy Statement-II: Proteins help the body in its growth, and repair of body cells and tissues. (A) Statement-I is true, Statement –II is false (B) Statement-I is false, Statement –II is true (C) Both statements are true (D) Both statements are false Match the following Column-I Column-II 1) Carbohydrate p) meat 2) Proteins q) groundnut oil 3) Fats r) spinach 4) Mineral salts s) potato (A) 1234/rpsq (B) 1234/sqpr (C) 1234/prqs (D) 1234/qsrp Assertion (A): The diet of anaemic patient should contain green leafy vegetables, eggs, groundnuts etc., Reason (R): Iodine deficiency leads to goitre (A) A is correct, R is the correct explanation of A (B) A is correct, R is the not the correct explanation of A (C) A is correct, R is incorrect (D) A is incorrect, R is correct (E) Both A and R are incorrect Statement-I: Mineral salts are required in large quantities by our body Statement-II: Vitamins salts are required in large quantities by our body (A) Statement-I is true, Statement –II is false (B) Statement-I is false, Statement –II is true (C) Both statements are true (D) Both statements are false Match the following Column-I Column-II 1) Carbohydrate p) leafy vegetables 2) Proteins q) jaggery 3) Fats r) pulses 4) Mineral salts s) milk (A) 1234/rpsq (B) 1234/sqpr (C) 1234/prqs (D) 1234/qsrp Which of the following is reaching carbohydrates? (A) Rice (B) Milk (C) Soya bean (D) Fish Which of the following is reaching proteins? (A) Rice (B) Milk (C) Soya bean (D) Fish Lack of iron in haemoglobin causes (A) Goitre (B) Typhoid (C) Malaria (D) Anemia Which of the following are required in small quantities by our body? (A) Vitamins (B) Minerals (C) Salts (D) All Which of the following helps in maintaining constant body temperature? (A) Carbohydrates (B) Fats (C) Water (D) Minerals

Conceptive Worksheet 1. 2. 3. 4.

5.

Food is required for (A) Energy (B) Growth (C) Repair (D) All The energy giving foods contain (A) Carbohydrates (B) Proteins (C) Vitamins (D) Minerals The foods that helping protection contain (A) Carbohydrates (B) Proteins (C) Vitamins (D) Minerals ____i_____ and ____ii_____ are required for making bones and teeth hard (A) i- Sodium ii- Magnesium (B) i- Calcium ii- Aluminium (C) i- Calcium ii- Phosphorus (D) i- Phosphorus ii- Magnesium Which of the following is reaching fats? (A) Rice (B) Milk

(C) Soya bean

(D) Fish

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Health and Hygiene 6.

7. 8.

Which of the following is reaching mineral salts? (A) Rice (B) Milk

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(C) Soya bean

Goitre is caused due to deficiency of (A) Calcium (B) Iron (C) Iodine The percentage of water content in normal human body is (A) 40% (B) 50% (C) 60%

(D) Fish

(D) Magnesium (D) 70%

3. CHARACTERISTICS OF GOOD HEALTH A person is said to be healthy or having good health, if he/she is (i) Not suffering from diseases. (ii) Free from unnecessary anxiety. (iii) Free from social and physiological tensions. (iv) Free from mental problems. (v) Having good self confidence. (vi) Not handicapped physically. (vii) Able to work efficiently. A person with above characteristics is active, cheerful, energetic and good at work. Certain conditions have adversely affected an individual's ability to maintain good health. For example, excessive human population has created (i) Overcrowded living conditions. (ii) Environmental pollution due to increased number of industries, vehicles and overpopulation. (iii) Unhygienic living conditions (polluted air, unclean drinking water, etc.). (iv) Malnutrition. 4. (i) (iii) (v) (vii) (ix)

FACTORS FOR MAINTAINING GOOD HEALTH Proper nutrition and balanced diet (ii) Proper food habits Personal and domestic hygiene (iv)Adequate physical exercise Proper recreation, rest and sleep (vi) Clean food, water and air Keeping away from smoking, drugs and alcohol (viii) Timely vaccination Avoiding exposure to radiations (x) Proper health education.

BALANCED DIET Our body requires balanced quantities of different nutrients — proteins, carbohydrates, fats, vitamins and minerals — for its proper growth and maintenance. Deficiency of one or the other nutrient in the food leads to poor health and makes it prone to disease. In general, our daily food consists of chapattis, rice, curd or buttermilk (lassi), dal, vegetables and salad. These food items provide us all the nutrients required by the body. Carbohydrates and proteins are supplied by chapattis and rice. Dal and milk provide the proteins. Curd or buttermilk supply carbohydrates, proteins, minerals and vitamins. Minerals, proteins, carbohydrates and fibre and provided by the vegetables and salads. Thus, the food consumed provides us with all the nutrients. The problem, however, arises when we eat only rice, while others eat only chapattis or bread. No single food item supplies all the essential nutrients in the amounts needed by the body. Wrong food habits result in malnutrition, as the food taken is lacking or deficient in essential nutrients. Malnutrition simply means faulty nutrition. Poverty in our country is responsible for another nutritional deficiency disorder termed undernutrition; this is due to inadequate intake of food in terms of quantity. A mixed diet containing all the essential requirements in their right quantities is necessary for body's proper growth. Such a diet is known as the balanced diet. In a balanced diet, energy-giving foods, body-building foods and protective foods are present in correct proportions.

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A balanced diet, thus, provides the body with (a) All the essential nutrients, (b) All the materials necessary for proper growth and repair of body, and (c) Energy required by the body to carry out its life activities. Over-eating may also lead to diseases. Obesity is one such disease. This often leads to other problems like heart diseases and high blood pressure. ADEQUATE EXERCISE, REST AND SLEEP 1. Live a disciplined life. 2. Keep yourself away from tension, long hours of television viewing and long hours of continuous table work. 3. Take rest and regular sleep. 4. Undertake exercise regularly. Brisk walking, running, cycling, and swimming are some good exercises. Exercises help in improving blood circulation. They also help in keeping our lungs, heart and body muscle healthy. Exercise also helps in resisting infections and building up health. PERSONAL CLEANLINESS The basic aim of maintaining personal cleanliness is to keep the bacteria and other harmful microorganisms away from entering the body or infecting the food consumed by us. Otherwise, diseases can develop. Hygiene is defined as the science of health and the prevention of diseases. Following precautions need to be taken for maintaining personal hygiene: 1. Before and after taking meals, always wash your hands with soap water. 2. Clean your teeth after each meal and before going to bed. Otherwise tooth decay may take place. 3. Take bath regularly with clean water. 4. Do not grow long nails. Keep them short and clean. 5. Clothes, especially undergarments, should be changed daily and wearing of very tight clothes must be avoided. 6. Clean and regular toilet habits must be adopted for maintaining good health. One should not defecate in the open. After defecation, hands and feet should be cleaned with water and soap. 7. The feet should be cleaned everyday and well protected. Injuries due to bacteria like tetanus, hookworms and insects may be caused if barefoot walk is undertaken. Walking barefooted must be avoided. 8. Hair should be cleaned regularly with soap and water. Combing removes the dirt sticking to hair. The comb, too, should be cleaned regularly. 9. Eyes should be washed daily with clean and cold water. Rubbing of eyes with hands should be avoided to prevent the entry of germs into the eyes. 10. The waste food material and garbage should be disposed off properly. It should not be thrown in the open. Covered bins must be employed. 11. Oral hygiene, Eye Care and Hair Care: Oral hygiene, eye care and hair care are aspects of personal hygiene. Cleanliness is most essential for maintaining the above aspects. A few suggestions to be followed are as follows: 12. Oral Hygiene: Oral hygiene is mainly concerned with the care of teeth. Teeth are commonly seen to become yellow and suffer from cavity formation. The yellowing of teeth is due to a sticky film of saliva, food particles and bacteria, and is called plaque. Plaque and cavity formation are often caused by the consumption of sweets. Bacteria present in the plaque convert the sugar into an acid which dissolves away the enamel of the tooth. Ultimately a hole or cavity is formed in the tooth. Plaque affects the gums too. The plaque builds up in the region where the teeth meet the gums, and forms a space. Bacteria growing in this space cause the teeth to fall.

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Plaque formation and other diseases can be avoided by (i) not eating foods like sweets, chocolates and ice-creams (ii) consuming foods such as raw vegetables, carrots, spinach (palak), radish, cabbage and fresh fruits (the teeth and gums get good exercise when fibrous foods are eaten), (iii) brushing teeth thoroughly and regularly everyday in the morning and again before going to bed, and (v) using fluoride toothpaste.

TEETH Teeth, present in the mouth cavity, play an important role in biting and chewing the food. In an adult human being, there are four types of teeth — incisors, canines, premolars and molars. Fixed to the gums, each teeth has following three parts (Figure 6.1) :

Figure 6.1: A tooth in section (i) Root, the part embedded in the jaw, (ii) Crown, the top part projecting above the gums, and (iii) Neck, the part between the root and the crown. Internally, there are three parts of a tooth — enamel, dentine and the pulp cavity. Enamel is the white part of the tooth, and is the hardest substance in our body. Below the enamel, dentine is present. Inner to dentine is the soft pulp cavity which contains blood vessels and nerves EYE CARE Suggestions concerning eye care are given below: (i) Eyes should be protected from bright sunlight. (ii) Television should not be watched continuously for long hours. (iii) While reading, the book or magazine should be kept at a distance of at least 30 cm from the eyes. (iv) Reading in dim light, or while lying down should be avoided, as it puts strain on the eyes. (v) Rubbing of eyes with hands should be avoided so as to prevent injury and the entry of germs into the eyes. (vi) Eyes should be washed with plenty of clean and cold water. (vii) Eye problems like trachoma and conjunctivitis spread through contamination with hand and personal articles like towels and handkerchiefs. Use of personal articles of others must be avoided. (viii) Foods rich in vitamin A which is good for eye should be included in the diet. Such food items include milk, butter, cabbage, spinach, carrot, tomato and mango. Deficiency of vitamin A causes a disease called night blindness, in which a suffering person can see during the day, but not at night. HAIR CARE Three problems are generally faced by people in respect of hair. These are early falling of hair, early graying of hair and dandruff. Hair arises from the skin and receives nourishment through the skin. If due to some reason, the hair does not receive the nutrients, they start falling. Dandruff is the formation of white flakes on the head and hair.

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Following are some of the suggestions for maintaining good hair growth: (i) Hair and scalp should be kept clean and free from parasites such as lice by regular washing and combing. (ii) Comb and towel of other persons should not be used. (iii) Scalp should be massaged regularly, in order to enhance blood circulation to the hair roots. (iv) Diet rich in raw vegetables and a balanced diet should be consumed. (v) Use of colouring agents or dyes should be avoided. 6. CLEANLINESS OF THE SURROUNDINGS — COMMUNITY HYGIENE Community hygiene in recent years has become a serious problem. Unhygienic conditions prevail in our surroundings. There are several factors responsible for the sorry state of affairs prevailing in cities. FACTORS AFFECTING THE CLEANLINESS (i) Ever-increasing population leading to overcrowding becoming a burden on the limited natural resources; overcrowding has led to poor and unhygienic living conditions with small houses lacking proper ventilation, toilet and drainage facilities. (ii) Increasing urbanisation to cope up with the increasing population; more houses, roads, and other facilities are required; (iii) Increasing industrialization, again to cope up with the increasing population. In order to fulfil his needs, man has brought about excessive clearing of the forests (deforestation). Consequently, our environment has gone down to a great extent, and pollution has emerged as a serious concern of today. Pollution needs to be dealt with for maintaining personal as well as community hygiene. MEASURES TO BE FOLLOWED FOR MAINTAINING COMMUNITY HYGIENE 1. Garbage and other discarded items should not be thrown in the open. These items should be put in a closed container or dustbin. 2. The garbage dumps should be kept clean. Insecticides must be sprayed. 3. Water should not be allowed to stagnate, as it breeds mosquitoes. In case the stagnated water cannot be emptied out easily, as in case of water coolers, kerosene oil may be sprayed on the surface of the stagnated water. 4. Do not defecate in the open. 5. Open drains, if any, should be covered. 6. Drinking water should not be contaminated by bathing or by washing clothes. 7. Safe and clean water and pollution-free surroundings are a must for maintaining hygiene. 8. Trees should be planted. SANITATION — DISPOSAL AND TREATMENT OF WASTES Proper sanitation is a must for healthy living. One important factor for maintaining sanitation is the disposal of wastes. There are several methods and one or more of these may be adopted for disposal of wastes and thus maintaining proper sanitation. 1. Dumping : Waste materials are dumped in pits which are made far away from the residential areas and agricultural land. The pits are subsequently covered with soil or sand. 2. Composting : In this technique, the waste material like that of vegetables, agricultural wastes and animal wastes (dung, urine) is put in a pit, where it is allowed to decay and decompose. After a few months, compost is formed. The compost is used as manure. 3. Sewage Treatment Plants: This method is used in big cities by the local municipal bodies. The wastes from the houses are carried to the treatment plants through sewer lines. Waste water after treatment is recycled while the solid waste is converted into manure. Thus, community hygiene includes (i) provision of clean drinking water and (ii) efficient methods for garbage and sewage disposal. In addition, provision of health clinics and health workers to maintain and improve community health are required.

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7. POLLUTION AND HEALTH Increasing human population has drastically lowered the quality of the environment — air, water and land — in which we live. This is creating a lot of health hazards for the humans. Pollution, which has thus resulted, is the introduction of unwanted usually harmful substances into the environment. Addition of harmful gases and other particles in the air has resulted in air pollution. The harmful gases are being released from the factories, automobiles, thermal power plants, and many other sources. Air pollution causes diseases like asthma, bronchitis and irritation in the eyes and throat. Similarly, water pollution makes water unfit for drinking. Some of the factors which cause water pollution are disposal of sewage and discharge of industrial wastes into rivers, bathing of humans and animals in or near water sources, and excessive use of fertilizers and insecticides. Polluted water causes serious water-borne diseases like cholera, typhoid, dysentery and jaundice.

Formative Worksheet 13.

14. 15.

16.

17. 18. 19. 20. 21. 22. 23.

24.

Excessive human population has created (I) Overcrowded living conditions. (II) Environmental pollution due to increased number of industries, vehicles and overpopulation. (III) Unhygienic living conditions (polluted air, unclean drinking water, etc.). (IV) Malnutrition. Choose the right option (A) I, III, IV (B) I, II, IV (C) I, III (D) I, II, III, IV Over-eating may also lead to (A) Malaria (B) Typhoid (C) Constipation (D) Obesity Statement-I: For a healthy life, we need to work hard for long hours Statement-II: Exercise also helps in resisting infections and building up health. (A) Statement-I is true, Statement –II is false (B) Statement-I is false, Statement –II is true (C) Both statements are true (D) Both statements are false Assertion (A): We need to comb our hair regularly Reason (R): Combing removes the dirt sticking to hair (A) A is correct, R is the correct explanation of A (B) A is correct, R is the not the correct explanation of A (C) A is correct, R is incorrect (D) A is incorrect, R is correct (E) Both A and R are incorrect The yellowing of teeth is due to a sticky film of saliva, food particles and bacteria, and is called (A) Opaque (B) Plaque (C) Plague (D) All Plaque formation and other diseases can be avoided by not eating (A) Sweets (B) Chocolates (C) Ice-creams (D) All Which of the following should be present in our tooth paste to prevent plaque and cavities? (A) Carbide (B) Bromide (C) Fluoride (D) Iodide The part of the teeth that is embedded in the jaw is (A) Root (B) Crown (C) Neck (D) None Internally, teeth has (A) Enamel (B) Dentine (C) Pulp cavity (D) All For a healthy sight, our food should be rich in vitamin (A) Vit. A (B) Vit. B (C) Vit. C (D) Vit. D The formation of white flakes on the head and hair is called (A) Dandruff (B) Night blindness (C) Trachoma (D) Conjunctivitis Water pollution causes (A) Cholera (B) Typhoid (C) Dysentery (D) All

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Conceptive Worksheet 9.

10.

11.

12.

13. 14.

15. 16. 17. 18.

19.

21.

A person is said to be healthy or having good health, if he/she is (A) Not suffering from diseases. (B) Free from unnecessary anxiety. (C) Free from social and physiological tensions. (D) All A balanced diet, thus, provides the body with (A) All the essential nutrients, (B) All the materials necessary for proper growth and repair of body, and (C) Energy required by the body to carry out its life activities. (D) All the above Obesity leads to (A) Heart diseases (B) High blood pressure (C) AIDS (D) Both (A) and (B) Which of the following precautions need to be taken for maintaining personal hygiene? (A) Before and after taking meals, always wash your hands with soap water. (B) Clean your teeth after each meal and before going to bed. Otherwise tooth decay may take place. (C) Take bath regularly with clean water. (D) All the above Eyes should be washed daily with (A) Cold water (B) Hot water (C) Clean water (D) Salt water Assertion (A): Plaque and cavity formation are often caused by the consumption of sweets Reason (R): Bacteria present in the plaque convert the sugar into an acid which dissolves away the enamel of the tooth (A) A is correct, R is the correct explanation of A (B) A is correct, R is the not the correct explanation of A (C) A is correct, R is incorrect (D) A is incorrect, R is correct (E) Both A and R are incorrect Plaque formation and other diseases can be avoided by not consuming (A) Sweets (B) Raw vegetables (C) Chocolates (D) Ice-creams In an adult human being, there are ______ types of teeth (A) One (B) Two (C) Three (D) Four The part of the teeth that projects above the gums is (A) Root (B) Crown (C) Neck (D) None Which of the following is an eye problem? (A) Plaque (B) Cavities (C) Trachoma (D) Conjunctivitis Deficiency of vitamin A causes (A) Plaque (B) Night blindness (C) Trachoma (D) Conjunctivitis Air pollution causes (A) Asthma (B) Bronchitis (C) Irritation (D) All

8. TRANSMISSION OF DISEASES Diseases are either due to (i) Imbalances in the diet, or due to (ii) Infection by micro-organisms. The environment in which we live — air, water and soil — has plenty of micro-organisms. The micro-organisms enter our body through. (i) The air we inhale, (ii) The water we drink, and the food we eat, and (iii) Skin.

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These can cause diseases, once they enter the human body. On the basis of whether the diseases could be spread from one person to another or not, the diseases may be communicable or non-communicable. Communicable diseases can spread from one person to another by means of air, water, food, physical contact with diseased person and insects. Examples : Malaria, cholera, tuberculosis, AIDS. Non-communicable diseases cannot be transmitted from one person to another. Examples : Deficiency diseases like rickets, goitre, marasmus. MODES OF TRANSMISSION Communicable diseases may be transmitted from the source of infection of susceptible individual in many different ways: I. Direct Transmission (i) Direct contact : Infection may be transmitted by direct contact from skin to skin, muscosa to mucosa, mucosa to skin. Examples: disease transmitted by direct contact include leprosy, skin and eye infections, AIDS. (ii) Droplet infection: Spread by direct spray of droplets of saliva during coughing, sneezing, speaking and spitting. Examples: whooping, cough, tuberculosis, diphtheria, common cold. (iii) Contact with soil: For example, hookworm larvae, tetanus, mycosis. (iv) Inoculation into skin/mucosa: The micro-organisms may be inoculated directly into skin/mucosa. Examples: rabies virus by dog bite, hepatitis B virus through contaminated needles and syringes. (v) Through contaminated food and water, as in cholera and typhoid. II. Indirect Transmission This embraces a variety of mechanisms including the traditional five F's — flies, fingers, fomites, food and fluid. (i) Transmission of micro-organisms through water and food; e.g., acute diarrhoea, typhoid, cholera, polio, hepatitis A, food poisoning and intestinal parasites all are transmitted by water and food. (ii) Transmission by blood; e.g., hepatitis B, malaria. (iii) Transmission of micro-organisms by an arthropod/any living carrier; e.g., by mosquito — malaria, dengue, filaria housefly — typhoid, cholera, poliomyelitis sand fly — kala-azar rat flea — plague (iv) Fomites include soiled clothes, towels, handkerchiefs, cups, spoon, toys, Diseases transmitted by fomites — diphtheria, eye and skin infection. (v) Unclean hands and fingers; e.g., typhoid, intestinal parasites. PREVENTION AND CONTROL Communicable diseases can be prevented by following the principles of personal and community hygiene, like (i) drinking clean and safe water. (ii) eating freshly prepared food, stored properly and kept away from flies and mosquitoes (iii) breathing in fresh air (iv) using a handkerchief while sneezing or coughing (v) washing the personal articles of the infected person separately, and with hot water (vi) protecting from mosquito-bites by using nets or mosquito repellents, and (vii) undertaking vaccination Vaccination is a method to protect the body against diseases. The protection against diseases is achieved by the administration of a substance called vaccine into the body. A vaccine is a weakened or killed disease-causing germ that will not cause the disease. This is the basis of immunization. Immunization develops the ability in the human body to fight infection. Many dreaded diseases like cholera, polio and hepatitis can be effectively prevented by this method. These days, a nation-wide programme to eradicate polio called ____________________________________________________________________________________________________

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"National Pulse Polio Programme" has been undertaken in our country. Polio vaccine is given orally (through mouth) and is called OPV (oral polio vaccine). DPT is a triple vaccine given to a newborn baby for protection against diphtheria, pertussis (whooping cough) and tetanus. 9. FIRST AID BURNS In case of burns, it is not only the damage to the skin surface, it is the heat which penetrates deep which matters. The heat disrupts the circulation and results in severe scarring. So rapid cooling is important.

Figure: 6.2 Cut away clothing near burned area

Figure 6.3: Hold burn under cold running water

Figure 6.4: Where burns occur to parts of the body that cannot be immersed, .apply thick material soaked in cold water • When someone's clothing or hair catches fire, put the fire off with water, if available. Otherwise smother the flames with a thick towel or blanket. Do not let the victim run. • If you catch fire, wrap yourself in a blanket or coat, or roll on the floor or the ground. Remove clothing that has been soaked in hot oil or boiling water immediately. Do not remove dry, burned clothing or any clothing that is sticking to a burn. Remove all rings or bracelets that could impede circulation to or away from the burned tissue. Do not apply ointment, such as petroleum jelly or butter to a burn. Do not cover with flufly things like cotton that will stick to the burn. Gently wash it with a mild soap and rinse it with water thoroughly. Keep the burn area elevated above the level of the heart. Leave the burn area uncovered unless it is likely to get dirty or cause pain when it rubs against clothing. In that case, put a light sterile bandage over the burned area. Change the dressing daily. Do not pop the blisters. Burn blisters will burst on their own in a few days. Remove the dead skin with a clean cloth and soap. • If you burn your tongue with a hot drink or food take few grains of sugar. Ice cold water can also be used. • Avoid exposing burned areas to the sun. Cooling the burn: Cool the burn immediately for 15-20 minutes with ordinary cold water. This reduces inflammation (swelling) and pain. Ice water is not needed. A small part like a burnt finger tip is held under a running tap. A hand or arm is kept immersed in a sink or a basin of water. For parts of the body which cannot be immersed (like face, chest or abdomen), thick towel soaked in water can be applied over the burnt area. Merely pouring water over the burnt area is not very effective. Precautions 1. Infection should not develop. If it happens, contact a doctor. 2. Also make sure that the victim had a tetanus injection. BRUISES For treating a bruise, a cold pack or an ice pack is required. Cover the bruise with a cold pack or an ice pack (figure. 6.5) for a few hours. This reduces pain and swelling.

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Consult a physician if a bruise is very large or if it swells up, or if there is difficulty in moving the bruised limb.

Figure 6.5: Applying cold pack on shoulder CUTS (i) Expose the cut, removing whatever clothing may be necessary. (ii) Wash the cut with soapy water and then hold it under cold running water. Make sure that all dirt or other undersirable material is removed. Use a cotton swab if necessary. (iii) Dry the cut with sterile gauze. (iv) Apply mild tincture of iodine all over the cut and the surrounding skin. (v) After the blood flow stops, lower the cut with a clean, dry, soft and absorbent dressing. (vi) Raise the cut area above the level of the heart, if possible. (vii) Do not disturb the clot of blood formed over the cut. Precautions 1. Ensure that the cut is not infected. 2. Ensure that tetanus injection is given to the victim to prevent infection. A cut should be seen by a physician if it is 1 inch in length or if it is on the face or over a joint. FIRST-AID KIT You can buy an already assembled first-aid kit from your local drugstore, or you can gather the following items in a box. It is a good idea to tape fix the emergency numbers (of the local hospital emergency, your family doctor, local police department, fire department) to the lid of the box. Also, keep a first-aid manual in the box. Keep the kit out of the reach of the small children. Items to be kept in the kit (a) Tools : Thermometer, Flashlight, Hot water bottle, Ice bag, Scissors, Packet of needles, Cotton swabs, Safety matches. (b) Dressings : Adhesive bandages, Cotton dressings (gauze bandages), Elastic bandage, Absorbent cotton. (c) Medicines : Dispirin, Antibiotic ointment, Antivomiting tablets, Antacid tablets, Powdered activated charcoal (for swallowed poisons), Alcohol or spirit, Tincture of iodine.

Formative Worksheet 25.

26. 27. 28.

Diseases are caused due to (A) Imbalances in the diet (B) Infection by micro-organisms (C) Both (A) and (B) (D) None of these Which of the following is a communicable disease? (A) Rickets (B) Malaria (C) Marasmus (D) Goitre Which of the following is a non-communicable disease? (A) Rickets (B) Malaria (C) Marasmus (D) Goitre Which of the following diseases is transmitted by direct contact from skin to skin? (A) Rabies (B) Tuberculosis (C) Leprosy (D) Hepatitis B

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29.

Whooping cough is transmitted by (A) Direct contact (B) Droplet infection (C) Contact with soil (D) Inoculation into skin Rabies virus is transmitted by (A) Car bite (B) Dog bite (C) Snake bite (D) Rat bite Which of the following diseases are transmitted indirectly? (A) Cholera (B) Typhoid (C) Tetanus (D) Diarrhoea __________ is a method to protect the body against diseases (A) Immunization (B) Vaccination (C) Infection (D) None ____________ develops the ability in the human body to fight infection (A) Immunization (B) Vaccination (C) Infection (D) None OPV is given for (A) Polio (B) Diphtheria (C) Pertussis (D) Tetanus When someone's clothing or hair catches fire, put the fire off with (A) Acid (B) Water (C) Petrol (D) Kerosene Statement-I: If we catch fire, we need to apply ointment, such as petroleum jelly or butter to a burn Statement-II: If we catch fire, we need to cover with flufly things like cotton that will stick to the burn (A) Statement-I is true, Statement –II is false (B) Statement-I is false, Statement –II is true (C) Both statements are true (D) Both statements are false Which of the following should be done when there is a cut? (A) Expose the cut, removing whatever clothing may be necessary. (B) Wash the cut with soapy water and then hold it under cold running water. Make sure that all dirt or other undersirable material is removed. Use a cotton swab if necessary. (C) Dry the cut with sterile gauze. (D) All Marasmus is a (A) Communicable disease (B) Non-communicable diseases (C) Both (A) and (B) (D) None of these Which of the following diseases is transmitted by direct contact from skin to skin? (A) Rabies (B) Tuberculosis (C) Leprosy (D) AIDS Which of the following is transmitted through contaminated food and water? (A) Cholera (B) Typhoid (C) Tetanus (D) Mycosis

30. 31. 32. 33. 34. 35. 36.

37.

38.

39. 40.

Conceptive Worksheet 22. 23.

24. 25.

26.

The micro-organisms enter our body through. (A) Air (B) Water (C) Skin (D) All AIDS is a (A) Communicable disease (B) Non-communicable diseases (C) Both (A) and (B) (D) None of these Which of the following is transmitted by contact with soil? (A) Hookworm larvae (B) Tetanus (C) Mycosis (D) All Match the following Column-I (mode of transmission) Column-II (diseases) 1) Blood p) typhoid 2) Mosquito q) diphtheria 3) Clothes r) dengue 4) Hands s) hepatitis B (A) 1234/pqrs (B) 1234/qprs (C) 1234/srqp (D) 1234/qsrp A vaccine _________ disease causing germ. (A) Weakens (B) Kills (C) Activates (D) None

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Health and Hygiene 27.

28. 29.

30. 31.

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Which of the following can be prevented by immunization? (A) AIDS (B) Typhoid (C) Cholera Which of the following is given against diphtheria? (A) OPV (B) DPT If you catch fire (A) Wrap yourself in a blanket or coat (C) Both (A) and (B) For treating a bruise, ___________ is used (A) Salt pack (B) Sugar pack First aid kit should contain (A) Thermometer (C) Antibiotic ointment

(D) Fever

(C) HIV

(D) All

(B) Roll on the floor or the ground (D) None (C) Cold pack

(D) Hot pack

(B) Adhesive bandages (D) All

SNAP SHOT 1.

Health is a state of physical, mental and social well-being.

2.

Disease is due to any disturbance in the working of the body. Diseases may be due to (i) imbalances in the diet (deficiency of essential nutrients in the diet results in deficiency diseases) or due to (ii) infection by micro-organisms.

3.

Food is essential for living organisms. There are six essential nutrients in our foodcarbohydrates, proteins, fats, vitamins, minerals and water.

4.

Food items may be energy-giving (carbohydrates and fats), growth-promoting (proteins) or protective (vitamins and minerals).

5.

Proper nutrition, balanced diet, proper food habits, personal and domestic hygiene, physical exercise, adequate rest, clean food, water and air, and proper health education are required for maintaining good health.

6.

Intake of inadequate food or unbalanced diet leads to malnutrition. Obesity results from overnutrition.

7.

Personal hygiene refers to maintaining an individual's own health.

8.

Community hygiene refers to maintaining the health and well being of all the members of the community and their surroundings.

9.

Diseases transmitted from one person to another are called communicable diseases. Cholera, diphtheria, typhoid and plague are some such diseases.

10.

Communicable diseases are transmitted through contaminated food, water, air and insects.

11.

To prevent infections, several measures could be adopted — boiling the water, milk and storing in proper containers, consuming freshly prepared food, chlorination of drinking water, preventing contamination of food, and keeping the surroundings clean.

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Summative Worksheet I. 1.

2.

3.

4.

5.

6.

II. 1. 2. 3.

Multiple choice questions. Sugars and starches are (A) Energy-giving foods (B) Body-building foods (C) Protective foods (D) All of the above Energy-giving foods are (A) Carbohydrates and fats (B) Carbohydrates and vitamins (C) Only carbohydrates (D) Carbohydrates and minerals Proteins are (A) Energy-giving foods (B) Growth-promoting foods (C) Protective foods (D) All of the above Which of the following is a eye problem? (A) Plaque (B) Trachoma (C) Anaemia (D) Kwashiorkor Cholera and typhoid are (A) Water-borne diseases (B) Air-borne diseases (C) Genetic diseases (D) Deficiency diseases Diseases which cannot be transmitted from one person to another are called (A) Deficiency diseases (B) Non-communicable diseases (C) Communicable diseases (D) None of the above

4. 5. 6.

Fill in the blanks: The body-building function of food is related to the presence of ________________. Energy-giving foods are rich in carbohydrates and/or ________________. Nutrient balance can only be achieved by supplying all nutrients in the correct and _________ proportions. To stay healthy, we should eat a ________________ Foods can be classified as , ________________ , and ________________. Conjunctivitis is a disease that affects ________________.

III. 1. 2. 3. 5.

Find the odd one out, giving reasons. Potato, coconut oil, honey, bread Cheese, egg, milk, groundnut Iodised salt, fish, seafood, cheese Over-eating, obesity, anaemia, high blood pressure

IV. 1. 2. 3. 4. 5. 6.

Classify the following habits as good or bad: Cleaning teeth after every meal. ________________ Putting finger inside the nose. ________________ Wearing clean clothes. ________________ Not consuming chocolates. ________________ Using hair dyes. ________________ Using fluoride toothpaste. ________________

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V. 1. 2. 3. 4. 5. 6.

Why do we need to undertake the following? Keeping the cooked food covered Developing the habit of cleanliness Not walking barefooted Washing and combing hair regularly Washing hands before and after every meal Using sufficient light for reading and writing.

VI. 1. 2. 3. 4. 5. 6. 7. 8. 9.

Answer the following questions: Define health. List three functions of food. Name the various nutrients in food. Name the three groups of foods. What are the two major factors responsible for the development of diseases. What is meant by a balanced diet? Mention five characteristics of good health. What can be done to maintain good health? Write, briefly about the following : (i) Personal cleanliness (ii) Eye care (iii) Oral hygiene (iv) Clean water (v) Clean air (vi) Clean food (vii) Hygiene What are communicable diseases? Give five examples. How are communicable diseases spread? List four agents. What is the aim of chlorinating water? How does pollution affect our health? What first aid steps would you take for (i) Cuts, (ii) Bruises, and (iii) Burns?

10. 11. 12. 13. 14.

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By the end of this chapter, you will understand  Learn about the factors which support life on the planet Earth  Describe the components of the environment  Distinguish between biotic and abiotic components of the environment  Understand the interdependence among living organisms  Learn about the role of decomposers in the environment  Gain knowledge about food chains, food webs and energy pathways  Understand pollution, its types, causes, and control measures  Know about useful plant and animal products.

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Chapter -7

Learning Outcomes

1. EARTH AS A UNIQUE PLANET In the primary classes you have learnt that the Earth is an enormously big spherical ball. You may have wondered that to you Earth appears flat and not a spherical ball. It is because at any place on the surface of the Earth, we do not have full view of the Earth. However, the astronauts travelling in space-ships have observed the Earth from large distances and taken its photographs. These photographs show that Earth is a spherical ball (Figure. 7.1). The Earth revolves around the Sun in a nearly circular path, which is commonly called orbit of Earth. It completes one Figure 7.1: The Earth as seen from revolution around the Sun in 365¼ days. the moon

Figure 7.2: The orbit of the Earth around the Sun The Earth also rotates about an imaginary axis, as it moves along its orbit. Due to this rotation of the Earth, different parts of it face towards the Sun one by one. It is due to the rotation of the Earth that day and nights are formed. Furthermore, the axis of the Earth is tilted to its orbit at an angle of 23½ . This helps in the formation of seasons as the Earth moves along its orbit. The earth appears stationary.

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It is because all the things around us on the surface of Earth move at the same speed. Thus, to an observer, nothing appears to move relative to one another and hence, the Earth appears stationary. Our solar system (Figure. 7.3) has eight planets, namely Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune. Depending on their distance from the Sun, Earth is the third planet. It is a unique planet in the sense that it is the only planet in the solar system which supports life.

Figure 7.3: Solar system REASON FOR LIFE ON EARTH Look at figure. 7.3. You find that the planet Mercury is closest to Sun and Neptune, the farthest. Mercury being closest gets too much of sun's heat, and therefore no life is possible on this planet. Our planet Earth is indeed unique and the features which are favourable for the existence of life on this planet are as follows — 1. Presence of Essential Elements: Proteins are the building blocks of life. Proteins contain carbon, hydrogen, oxygen and nitrogen as the essential elements. The Earth contains these elements in sufficient amount. It is these elements which first combine to form simple molecules. The simple molecules then combine to form complex molecules of proteins. 2. Presence of Oxygen: The life can function only if there is a way to release controlled amount of energy within the body of living beings. This is possible only when oxygen reacts with food materials during respiration. The Earth has a large amount of oxygen in the atmosphere, which is essential for respiration. 3. Presence of Water: Water is extremely essential for all forms of living beings. Water regulates body temperature and also various body systems of living beings, such as nutrition, respiration, excretion, etc. The Earth has vast reserves of water, which is essential for. life. 4. Temperature of Earth: The temperature on the surface of planet Earth is neither too low nor too high. The temperature at most of the places on the Earth varies between 20°C and 48°C. In this temperature range, one or another life form can sustain itself 5. Presence of Atmosphere: Some of the rays coming from the Sun are extremely harmful to the living beings. These can cause instant death in some organisms. The atmosphere acts as a protective blanket. It absorbs the harmful radiations of the Sun. Furthermore, atmosphere helps in the even distribution of heat energy from the Sun and in the formation of important elements of weather, such as clouds, rains, snow, etc. 6. Right amount of Mass and Gravitational Force: The Earth has the right amount of mass. It is this mass which produces strong gravitational force. This force pulls the bodies on or above the surface of the Earth inwards. This not only keeps the things on the surface of the Earth in place, but also holds the atmosphere and the oceans in place.

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Right distance of the Earth from the Sun: The distance of the Earth from the Sun is 149,600,000 km. Most of the places on the surface of the Earth receive the right amount of solar heat and the temperature stays between - 20°C and 48°C. This temperature is just right for sustaining life.

2. STRUCTURE OF THE EARTH Firstly, there is the planet Earth itself, called the geosphere. The outer, rocky part around the Earth (the geosphere) is called the lithosphere. The depressions in the lithosphere are filled with vast oceans and are called the hydrosphere. About 70 per cent of earth's surface is hydrosphere. Surrounding the lithosphere is an envelope of air, known as the atmosphere. The atmosphere is divided into a number of layers, the lowest being the troposphere, followed by the stratosphere and finally the ionosphere which is 80 km from the surface of the Earth. Most of the weather formation takes place in the troposphere. Thus, the planet Earth consists of three parts — (i) Lithosphere, (ii) Hydrosphere and (iii) Atmosphere. Inside of the Earth (geosphere) is also made of layers (Figure. 7.4). At the centre is a solid inner core made up of iron and nickel under very large pressure. Surrounding the inner core is the outer core which is liquid in nature and is mostly made up of iron, nickel and sulphur. Surrounding the outer core is the mantle, which is 2900 km in thickness. It is made up of molten light materials, commonly called magma. The magma within the mantle rises up and falls down as a result of heating and cooling of magma. The most important layer of Earth from the point of view Figure 7.4: Inside the Earth of all living beings, including human beings, is its crust. The Earth's crust provides all the materials necessary for the growth and existence of life. The Earth's crust contains these materials in various forms such as rocks, soil, water and air. The materials which are found in the Earth's crust are called minerals. Coal, petroleum, natural gas, lime stone, sand, common salt, ores of metals are examples of common minerals. The minerals which are found in the fertile soil or water are essential for all living beings. The materials and minerals found within the Earth's crust play an important role in the lives of human beings especially for their comfort and leisure. Coal and petroleum products mined from the Earth's crust provide for the energy needs of human beings. Metals like gold, silver, copper, aluminium, iron are used in making jewellery and various kinds of machines and shutters. The sand, the clay and the lime stone are used for making pottery and cement. COMPOSITION OF THE ATMOSPHERE The atmosphere contains a mixture of the following gases : (i) Nitrogen 78% (approx.) (ii) Oxygen 21% (approx.) (iii) Carbon dioxide (0.03% to 0.04%) (iv) Noble gases 0.9% (v) Water vapour (approx. 4% of the total volume of air) Besides the above gases, the lower layers contain sulphur dioxide gas, carbon, dust particles, salts and pollen grains, etc. In the upper layers of air, the percentage of oxygen drops rapidly. It is on account of this reason that the mountaineers carry oxygen cylinders with them. Similarly, high altitude fliers carry oxygen cylinders. Compared to the size of Earth, the thickness of Earth's atmosphere is too small. 99% of air is found upto the height of 30 kilometres above the surface of Earth. The gases present in the atmosphere are important for life to exist. Oxygen is required for respiration and carbon dioxide is required by the plants for photosynthesis. Atmosphere also contains another gas called ozone which is extremely useful for living beings. Ozone prevents the harmful ultraviolet rays from reaching the Earth. It, thus, acts as a protective layer. www.bemedicos.com ____________________________________________________________________________________________________

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IMPORTANCE OF ATMOSPHERE 1. It acts as a protective blanket for the Earth. It absorbs most of the harmful radiations such as ultraviolet radiations and X-rays coming from the Sun. 2. Uneven heating of atmosphere sets up wind cycles. These wind cycles help in circulating the air and also cause rain. 3. The circulation of the air produces different climatic zones. This, in turn, has produced different kinds of plants and animals in different regions. 4. It is a source of oxygen, which is required for respiration by all the plants and animals. 5. It provides oxygen for burning the fuels for various domestic or industrial purposes.

Formative Worksheet 1.

2.

3. 4. 5.

6.

7.

8.

9.

10. 11. 12. 13.

Statement-I: It is due to the rotation of the Earth that day and nights are formed. Statement-II: The axis of the Earth is tilted to its orbit at an angle of 23½ . (A) Statement-I is true, Statement –II is false(B) Statement-I is false, Statement –II is true (C) Both statements are true (D) Both statements are false Assertion (A): The earth appears stationary. Reason (R): It is because all the things around us on the surface of Earth move at the same speed (A) A is correct, R is the correct explanation of A (B) A is correct, R is the not the correct explanation of A (C) A is correct, R is incorrect (D) A is incorrect, R is correct (E) Both A and R are incorrect The closest planet to the sun in solar system is (A) Mercury (B) Venus (C) Earth (D) Mars The largest planet of the solar system (A) Earth (B) Jupiter (C) Saturn (D) Uranus Statement-I: Life exists on the Mercury Statement-II: Life exist on the Earth (A) Statement-I is true, Statement –II is false (B) Statement-I is false, Statement –II is true (C) Both statements are true (D) Both statements are false Statement-I: The temperature on the surface of planet Earth is neither too low nor too high. Statement-II: Atmosphere is not present on Earth (A) Statement-I is true, Statement –II is false (B) Statement-I is false, Statement –II is true (C) Both statements are true (D) Both statements are false The temperature at most of the places on the Earth varies between (A)  10°C and 100°C (B)  20°C and 48°C (C) 50°C and 100°C (D)  200°C and 48°C The presence of atmosphere on earth helps in (A) absorption of harmful radiations coming from the sun (B) formation of clouds and rain (C) killing people (D) occurrence of earth quakes The distance of the Earth from the Sun is (A) 149,600,000,00 km (B) 149,600,000 km (C) 149,600,0 km (D) 149,600 km About _____ per cent of earth's surface is hydrosphere. (A) 40 (B) 50 (C) 60 (D) 70 Most of the weather formation takes place in the (A) Troposphere (B) Stratosphere (C) Ionosphere (D) Lithosphere The common element present in inner core and outer core of earth is (A) Iron (B) Nickel (C) Sulphur (D) Phosphorus The percentage of nitrogen present in earth’s atmosphere is (A) 0.03% to 0.04% (B) 0.9% (C) 21% (D) 78%

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97 14.

15.

16.

Match the following with respective composition of different gases in earth’s atmosphere. Column-I Column-II 1) Nitrogen p) 4% 2) Oxygen q) 0.03% 3) Carbon dioxide r) 21% 4) Water vapour s) 78% (A) 1234/srpq (B) 1234/qspr (C) 1234/prsq (D) 1234/srqp Assertion (A): Mountaineers carry oxygen cylinders with them while climbing higher altitudes. Reason (R): In the upper layers of air, the percentage of oxygen rises rapidly. (A) A is correct, R is the correct explanation of A (B) A is correct, R is the not the correct explanation of A (C) A is correct, R is incorrect (D) A is incorrect, R is correct (E) Both A and R are incorrect Assertion (A): Ozone present in earth’s atmosphere proves to be useful. Reason (R): Ozone prevents the harmful ultraviolet rays from reaching the Earth (A) A is correct, R is the correct explanation of A (B) A is correct, R is the not the correct explanation of A (C) A is correct, R is incorrect (D) A is incorrect, R is correct (E) Both A and R are incorrect

Conceptive Worksheet 1. 2. 3. 4. 5. 6.

7.

8. 9. 10. 11. 12.

The Earth revolves around the Sun in a nearly circular path, which is commonly called (A) Axis (B) Orbit (C) Orbital (D) None Earth completes one revolution around the Sun in (A) 365¼ days (B) 300 days (C) 265¼ days (D) 200 days Our solar system has _______ planets. (A) 6 (B) 7 (C) 8 (D) 9 Earth is _____ planet from the sun (A) First (B) Second (C) Third (D) Fourth The farthest planet from the sun in the solar system is (A) Mercury (B) Earth (C) Neptune (D) Uranus Which of the following is the reason for the existence of life on the Earth? (A) Presence of essential elements (B) Presence of oxygen (C) Presence of water (D) All the above Which of the following keeps the things on the surface of the Earth in place, but also holds the atmosphere and the oceans in place (A) Temperature (B) Oxygen (C) Gravitation of force (D) None The outer, rocky part around the Earth is called the (A) Geosphere (B) Hydrosphere (C) Lithosphere (D) None The lowest layer of atmosphere is (A) Troposphere (B) Stratosphere (C) Ionosphere (D) Lithosphere Mantle is made up of molten light materials, commonly called (A) Protoplasm (B) Cytoplasm (C) Magma (D) Matrix Which of the following is the least abundant in earth’s atmosphere? (A) Nitrogen (B) Oxygen (C) Carbon dioxide (D) Noble gases Oxygen is the _______ abundant element in earth’s atmosphere (A) First (B) Second (C) Third (D) Fourth

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3. ENVIRONMENT Moon is not a good place for life to exist. The Earth is the only planet in the Solar System where life is found. Plants and animals exist on the Earth because it has all the favourable conditions required for the survival of life. Even on the Earth, life is not found everywhere. The part of the Earth where plants and animals exist is called the biosphere. We find a variety of plants and animals occur in different places. While some of the plants and animals may be common, some may be different. At different, places different climatic conditions are prevalent. In some places, it may be too hot and in others it may be too cold. Similarly, some places may be dry while others may be having heavy rainfall. The plants and animals have become adapted to their surroundings. Look at the plants found in a lake and those in a desert area. The differences which you find relate to the environment of the plants. Air, water and soil form part of the surroundings of plants and animals including man. Living organisms do not live in isolation. All living things interact with one another and also interact with the non-living surroundings in which they live. The term environment is used to denote all living and non-living things. In other words, the living organisms and their surroundings constitute the environment. 4 .COMPONENTS OF THE ENVIRONMENT Environment broadly has three components: (a) Plants and animals, called biotic or living component; and (b) Non-living - air, water, light, temperature, clouds and soil, called abiotic or non-living component. (c) There is one more component of the environment, called the cultural component which consists of the human influences on the environment. Under natural conditions, both biotic and abiotic components together constitute the natural environment. Man is a dominant part of the natural environment, and is the only organism on this planet who has the capability to change the natural environment. Man's ever-increasing numbers and his greed to possess more and more physical comforts of life have greatly modified the natural environment. This modified natural environment or man-made environment is also termed sociocultural environment. Socio-cultural environment has adversely affected the quality of our environment. We do not have clean air to breathe, safe and clean water to drink. Instead, we have congested roads, a highly polluted atmosphere and a large number of tall buildings and industries to cope with the increasing population. TERMS RELATED TO THE COMPONENTS OF ENVIRONMENT The following terms are often used while studying the living organisms and their interaction with their surroundings. Habitat: The place where the organisms live is called the habitat. A plant or an animal is adapted to survive in its habitat. For example, the habitat of a lion is the forest. There are many types of habitats (Figure.7.5). Various physical factors like temperature, light, rainfall and soil conditions are not the same in different habitats. Population: A population is the total number of individuals (of plants or animals) of the same kind living in one area. Figure 7.5: Different habitat Community: A community is all the plants and animals that live together in one area or habitat. A community, thus, includes the different populations of plants and animals that exist in an area. The different populations depend on one another. For example, plants provide food to the animals. They keep the air fresh by returning oxygen to the surroundings. They also provide shelter to the animals from predators, heat and rain. In turn, animals provide carbon dioxide to the plants for manufacturing food (photosynthesis). Animals provide nutrients after their death and decay to the plants.

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Ecosystem: The plants and animals together with the non-living environment in a given habitat form an ecosystem. The plants and animals in an ecosystem interact with each other and with the environment to produce all the materials they need for their existence. Thus, an ecosystem is a selfcontained unit. 5. (i) (ii) (iii) and (iv)

LIVING OR BIOTIC COMPONENT The living component consists of plants and animals including humans. Plants, more specifically green plants which manufacture food, are called producers. Animals feed on plants directly or indirectly. Animals which feed directly on plants like cow goat, are called herbivores or plant eaters. Animals which eat herbivores, such as lion. Such animals are called carnivores or animal eaters. (v) Herbivores and carnivores are together called consumers, as these cannot manufacture their own food and consume plants or animals, as their food source. (vi) Some organisms which cannot be seen with the naked eye, called micro-organisms, form a part of the living component. Bacteria and fungi and such organisms. (vii) Green plants prepare food by the process called photosynthesis. Using carbon dioxide from the air and water from the soil, they prepare food in the presence of sunlight and green pigment, chlorophyll. Sunlight Carbondioxide  Water   Food  Oxygen Chlorophyll

 Carbohydrate 

(viii) Animals, on the other hand, are called heterotrophs as they cannot prepare their own food and depend on plants. (ix) In addition to producers and consumers, there is another category of living organisms which derive their food from the dead and decaying plants and animals. These are called decomposers, as they decompose the dead decaying matter. (x) Decomposers are important in the cycling of nutrients or minerals in nature (Figure. 7.7). (xi) Micro-organisms such as bacteria and fungi act as decomposers. (xii) These micro-organisms convert the dead bodies into simpler compounds like CO2, N2, H2O, H2S, etc. which enter the soil or are released into the atmosphere. (xiii) These simpler compounds can then be used again by the plants. This is how minerals are recycled in nature. Figure 7.7: Cycling of minerals by decomposers (xiv) Animals that feed on dead flesh are called scavengers. Examples : Hawk, crows, jackals, vultures. Plastic Bags! These days, you may have heard a lot about the ban on the use of plastic bags. Why so ? Why people are advised to use paper bags rather than plastic ones ? This has something to do with the role of decomposers. Certain items like vegetables, fruits, leaves, paper and cloth get easily decomposed, while others like plastic bags and bottles are not degradable. Paper, garbage and cloth are termed biodegradable and plastic is called non-biodegradable. Biodegradable items undergo cycling, whereas non-biodegradable ones cannot be recycled and adversely affect the environment and cause air pollution on being burnt.

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INTERACTIONS BETWEEN LIVING THINGS AND THE NON-LIVING SURROUNDINGS Living organisms (biotic component) require nutrients (abiotic components) for sustaining life. In an ecosystem, as discussed above, cycling of nutrients or minerals takes place from the living to non-living components and vice versa. This cycling of minerals is made possible through the activity of decomposers. The simpler substances so produced are taken up by the green plants, through the soil as well as through the atmosphere. Whether it is life on land or in water, energy produced by green plants in the form of food materials flows through the consumers, thus making animal life possible. Finally, the decomposers do their bit in releasing the nutrients from dead and decaying plant and animal life. Through this interaction between living and non-living components, an equilibrium is maintained in the biological world in terms of nutrients and energy.

Figure 7.8: A food chain shows the food relationship among plants and animals

FOOD CHAINS All living things need food to live. If they are starved of food, they get weak and finally die. As described above, plants are the food producers, while animals are food consumers. A food relationship exists between plants and animals. In this relationship, one living thing is consumed by another, and is shown by a food chain (Figures 7.8 and 7.9). A food chain is a diagram or a chain showing what animals eat, or a chain showing the process of "eating and being eaten". Each arrow in a food chain means "is eaten by". In the example given above, the grass or carrot is eaten by the rabbit, and the rabbit is eaten by the fox or lion. The last link of a food chain is occupied by the decomposers. Examples of food chains: (a) Plants  Human beings (b) Grass  [Rabbit/Deer/Sheep]  Lion (c) Grass  Insects  Birds (d) Algae  Insects  Small fish  Large fish (e) Grass  Insects  Frog  Snake  Eagle (See figure 7.9) (f) Small plants and animals in water  Small fish  Large fish In Figure 7.9 a grasshopper eats a plant, a frog eats the grasshopper, a snake eats the frog and a hawk eats the snake.

Figure 7.9: A food chain ____________________________________________________________________________________________________

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101 The general plan of a food chain, as evident from the above examples, is: Producers  Herbivores Small carnivores  Big carnivores.

FOOD WEB In nature, simple food chains do not operate. Rather, a number of food chains are interconnected. This is because green plants are eaten by several plant-eaters (herbivores). These plant-eaters are, in turn, eaten by several animal-eaters (carnivores). The animal-eaters may be eaten by other animal-eaters. In this way, many food chains become linked together to form a food web (Figure 7.10).

Figure 7.10: A food web ENERGY PATHWAYS In a food chain, transfer of energy takes place from one organism to another in the form of food transfer from producers to herbivores to carnivores. In other words, food chains show energy pathways or energy flow. In this energy flow, Sun is the primary source of energy (Figure 7.11). Energy from the Sun is used by plants to make food. This energy then goes to all animals through the food chain. Eventually the food stored in plants and animals is broken down to simple substances by decomposers. Plants make use of these simple substances as food. Figure. 7.11 shows how plants and animals depend on the Sun as their source of energy.

Figure 7.11: Energy flow: From the sun to the plants and animals

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Formative Worksheet 17. 18. 19.

20. 21.

22.

23.

24.

Which of the following components of a pond ecosystem is biotic in nature? (A) Detritus (B) Oxygen (C) Algae (D) Water Which of the following factors are biotic components of the ecosystem? (A) Soils (B) Fungi (C) Rocks (D) Minerals i and ii are the abiotic factors of the ecosystem. The information in which row completes the given statement? (A) i- Sunlight ii- Consumers (B) i- Wind ii- Decomposers (C) i- Water ii-Soil (D) i-Producers ii-Scavengers A constant flow of solar energy to various trophic levels is supplied by the (A) Carnivores (B) Omnivores (C) Herbivores (D) Producers Consumers are organisms that are dependent on other organisms for food. Which of the following organisms is not a consumer? (A) Cow (B) Lion (C) Plant (D) Rabbit The following food chain exists in an enclosed forest region. Plants → Rabbit → Fox Which of these is a consequence of the excessive hunting of rabbit population by humans? (A) The plant population remains unaffected (B) The food chain remains unaffected (C) The fox population decreases (D) The fox population increases Phytoplanktons → Zooplanktons → Small fishes → Large fishes → Killer whales The population of small fishes will increase with (A) An increase in the population of phytoplanktons (B) A decrease in the population of zooplanktons (C) A decrease in the population of killer whales (D) An increase in the population of large fishes In the given food chain, ____i___ is the producer and _____ii____ is the decomposer.

The information in which row completes the given statement? (A) i- Plant ii- Mouse (B) i-Eagle ii-Mouse (C) i-Plant ii-Mushroom (D) i-Eagle ii- Mushroom 25.

26.

In the given food chain, the decomposer is (A) Mushroom (B) Reindeer (C) Hyena The animals shown in the given figure form a part of a food chain.

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(D) Plant

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27.

What is the order in which energy flows in the food chain formed by the given organisms? (A) Shrew → Grasshopper → Plant → Hawk (B) Plant → Grasshopper → Shrew → Hawk (C) Shrew → Plant → Hawk → Grasshopper (D) Plant → Shrew → Hawk → Grasshopper The give food chain exists between plants, insects, lizard, snake, and hawk in a forest.

29.

Suppose an accidental spraying of a chemical in the forest leads to death of all the insects. Based on the given food chain, the death of insects will result in the increase in the population of the (A) Plant (B) Lizard (C) Snake (D) Hawk The illustration represents a food web operating in a forest. If the rat population decreases, then which of the following observations will be most probably true? (A) Decrease in the snake population (B) Decrease in the insect population (C) Increase in the hawk population (D) Increase in the fox population The illustration represents a marine food chain.

30.

If the penguin population decreases, then which of the following observations will be most probably true? (A) Increase in the killer whale population (B) Decrease in the phytoplankton population (C) Increase in the fish and the killer whale population (D) Decrease in the fish and the phytoplankton population The given illustration represents an ocean food web.

28.

Which two labels represent the producers in the given food web? (A) I and II (B) IV and V (C) VII and VIII

(D) X and XI

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Our Environment 31.

The given illustration represents a food chain operating in a forest.

32.

Which organism is the decomposer in the given food chain? (A) Rabbit (B) Fungi (C) Plant The illustration represents a food chain.

33.

34.

104

(D) Owl

If the population of the dragonfly larva increases, then which of the following observations will be most probably true? (A) Increase in the perch population (B) Decrease in the algae population (C) Decrease in the human population (D) Increase in the mosquito larva population In a forest, the illustrated food chain exists between the plants, insects, frog, snake, and the hawk populations.

If the frog population decreases because of some natural catastrophe, then which of the following recorded observations will be most probably true? (A) Decrease in the hawk population (B) Decrease in the insect population (C) Increase in the snake population (D) Increase in the plant population The illustration represents a food web operating in a forest.

Which organism is the producer in the given food web? (A) Hawk (B) Grass (C) Frog

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(D) Rat

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105 35.

The illustrated food chain operates in a forest.

36.

If most of the rat population died because of a disease, then which of the following observations would be most probably true? (A) The plant population will increase. (B) The grasshopper population will increase. (C) Both plant and hawk population will increase. (D) Both grasshopper and hawk population will increase. The illustration represents a food chain.

37.

Which organism is a decomposer in the given food chain? (A) Fox (B) Plant (C) Rabbit The illustration represents a food chain.

38.

The consumers in the given food chain are labeled as (A) I, II, III, and IV (B) II, III, IV, and V (C) IV, V, and VI (D) I, III, and VI The illustration represents a food chain operating in a forest.

39.

40.

(D) Mushroom

Which label represents the decomposer in the given food chain? (A) I (B) II (C) IV (D) V The highlighted portion in the food web represents a food chain. Which organism is the secondary consumer in the given food chain? (A) Mouse (B) Grass (C) Hawk (D) Snake The illustration represents a food web operating in grassland.

Which two labels represent the primary consumers in the given food? (A) I and II (B) II and III (C) IV and V

(D) V and VI

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41.

42.

43.

In the given food web, if there is an increase in the snake population, then there would be a decrease in the population of (A) Grasshoppers (B) Eagles (C) Ants (D) Rats The given food chain exists in a particular forest.

The competition for food will increase in the lion community by the introduction of (A) Plants (B) Eagles (C) Squirrels (D) Leopards Which of the following figures depicts the flow of energy in a terrestrial food chain? (A)

(B)

(C)

(D)

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The given figure shows an aquatic food chain.

45.

Who is the producer in the given food chain? (A) Larva (B) Algae (C) Perch Which organism is not a consumer in the given pond food chain?



46.

(A) Bear (B) Frog The given figure represents a food web.



(D) Dragonfly



(C) Crane

A decrease in the population of rabbits will greatly affect the population of (A) Hyenas (B) Snakes (C) Hawks

(D) Weed

(D) Frogs

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47.

The given figure shows a food web in a grassland ecosystem.

48.

In the given food web, the sources of energy for hawks are (A) Mice and sparrows (B) Sparrows and deer (C) Rabbits and mice (D) Deer and rabbits The given figure shows a food web in a particular forest.

49.

50.

The introduction of deer population in the given forest will result in (A) A decrease in fox population (B) An increase in rat population (C) An increase in owl population (D) A decrease in rabbit population The given figure shows a farm food chain. Plant  Grasshopper  Mouse  Snake Eagle In the given food chain, a decrease in mice population will cause an increase in the population of (A) Locusts (B) Snakes (C) Plants (D) Eagles The given figure represents the energy pyramid of a food chain.

Which of the following changes will not be noticed if all the secondary consumers in the given food chain die? (A) Decrease in the population of the tertiary consumers (B) Increase in the population of the primary consumers (C) Decrease in the population of the top consumers (D) Increase in population of the producers

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Which of the following organisms is a source of energy for the sparrow?

52.

(A) Squirrel (B) Spider The given figure shows a food web.

53.

(C) Aphid

(D) Oak

The transfer of energy is the least between (A) Owl and fox (B) Rabbit and fox (C) Mouse and owl (D) Rabbit and mouse If 200 J of energy is present at the plant level, then the amount of energy received by the eagle will be

(A) 200 J

(B) 20 J

(C) 2 J

(D) 0.2 J

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Conceptive Worksheet 13.

19.

Biotic and abiotic components interact with each other in an ecosystem. Which of the following components of a grassland ecosystem is abiotic in nature? (A) Grass (B) Deer (C) Lion (D) Soil Among soil, water, plants, rocks, and insects, the biotic components of the ecosystem are (A) Soil and water (B) Insects and soil (C) Water and plants (D) Plants and insects Producers are organisms that produce organic material from inorganic material and provide energy to animals directly or indirectly. Which of the following organisms is not a producer? (A) Chemosynthetic bacteria (B) Blue-green algae (C) Phytoplanktons (D) Zooplanktons Producers occupy which trophic level? (A) First (B) Second (C) Third (D) Fourth Producers are organisms that manufacture their own food. Which of the following organisms is not a producer? (A) Mango tree (B) Apple tree (C) Bacteria (D) Algae The population of which of the following animals would decrease with an increase in the tiger population of a forest ecosystem? (A) Fox (B) Deer (C) Snake (D) Hyena Take the given food chain into account

20.

Which of the following processes is depicted by the given arrow diagram? (A) Transfer of energy between organisms (B) Increase in the production of energy by organisms (C) Increase in the transfer of energy between organisms (D) Transfer of energy between biotic and abiotic components of the ecosystem The given figure shows a food chain operating in a terrestrial habitat.

14.

15.

16. 17.

18.

Which organism is the primary consumer in the given food chain? (A) Owl (B) Plant (C) Rabbit

(D) Fungus

In the given food chain, the producer is (A) Bacteria (B) Rabbit

(D) Plant

21.

(C) Hyena

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The illustration represents a forest food chain.

23.

If the population of squirrel increases, then which of the following observations will be most probably true? (A) The population of plants will increase. (B) The population of the fox will increase. (C) The population of snake and fox will decrease. (D) The population of snake and plants will decrease ___i__ and ___ii___ are the consumers in the given food chain.

24.

The information in which row completes the given statement? (A) i- Plants ii-reindeer (B) i-Reindeer ii-Mushroom (C) i-Mushroom ii-Hyena (D) i-Reindeer ii-Hyena The illustration shows a food web operating in a pond.

If the crane population decreases because of excessive hunting by humans, then which of the following observations will be most probably true? (A) The frog population will decrease. (B) The butterfly population will increase. (C) The fish and frog population will increase. (D) The bear and the butterfly population will increase.

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26.

27.

28.

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The illustration represents a marine food chain.

If the killer whale population increases, then which of the following observations will be most probably true? (A) Increase in the seal population (B) Increase in the shrimp population (C) Decrease in the shrimp and the seal population (D) Decrease in the shrimp and the phytoplankton population The illustration represents a food web. Which label represents the producer in the given illustration? (A) I (B) II (C) III (D) IV Decomposers are organisms that decompose the remains of dead plants and animals to aid the recycling of matter.

Which organism is the decomposer in the given food chain? (A) Caribou (B) Grass (C) Wolf The illustration represents a food web.

(D) Fungi

If the snake population decreases, which of the following observations will be most probably true? (A) The frog population will increase. (B) The grasshopper population will increase. (C) The hawk and the rat population will decrease. (D) The hawk and the frog population will decrease.

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29.

Consumers are the organisms that cannot manufacture their own food and are dependent on other organisms for food. The illustration represents a food chain.

30.

Which of the following pairs of organisms represents the consumers in the given food chain? (A) Plant and beetle (B) Lizard and beetle (C) Plant and bacteria (D) Lizard and bacteria The illustration represents a food web operating in an ocean.

31.

Which organism is a producer in the given food web? (A) Phytoplankton (B) Killer whale (C) Small fish The illustration represents a food chain.

(D) Squid

Which organisms are consumers in the given food chain? (A) Plants and caribou (B) Caribou and wolf (C) Wolf and bacteria (D) Fungi and plants

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The illustration represents a food web.

33.

Which organism is the primary consumer in the given food web? (A) Frog (B) Plants (C) Insects The illustration represents a marine food chain.

34.

114

(D) Pigeon

Which organism is the producer in the given food chain? (A) Algae (B) Sea lion (C) Bacteria (D) Small fish The highlighted portion of the given food web represents one of the food chains operating in the food web.

Which organism is the tertiary consumer in the given food chain? (A) Ant (B) Fox (C) Snake

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(D) Cougar

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The illustration represents a food chain.

36.

Which organism is the decomposer in the given food chain? (A) Fox (B) Plant (C) Fungi The illustration represents a food chain operating in an ocean.

37.

Which organism is the decomposer in the given food chain? (A) Crab (B) Mussel (C) Bacteria (D) Phytoplankton The illustration shows an ocean food web.

38.

If the population of shrimp decreases, then which of the following populations would decrease? (A) Fish (B) Crab (C) Lobster (D) Zooplankton The given figure represents a food web in a forest.

In the given food web, snakes obtain energy from (A) Foxes and owls (C) Owls and rabbits

(D) Caterpillan

(B) Frogs and foxes (D) Rabbits and frogs

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39.

Who are the producers in the given food chain?

40.

(A) Salmons (B) Herrings The given figure represents a food web.

41.

Who is the producer in the given food web? (A) Rabbit (B) Plant (C) Deer The given figure represents the food web of a river.

(C) Zooplanktons (D) Phytoplanktons

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(D) Fox

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42.

43.

A decrease in trout population will lead to (A) A decrease in the population of algae and diatoms (B) An increase in the population of herons and shrimps (C) A decrease in the population of small fish and worms (D) An increase in the population of leeches and dragonflies Which organism will be the most affected if the mouse is removed from the given food web?

(A) Eagle (B) Snake (C) Hyena (D) Sparrow Which of the following organisms in the illustrated food web receives the least amount of energy?

(A) Plant

(B) Hyena

(C) Rabbit

(D) Mouse

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45.

118

The given figure shows the aquatic food web of a particular region. Humans begin consuming more snails in the said region.

The over fishing of snails by humans will greatly affect the (A) Trout population (B) Crayfish population (C) Cyprinid population (D) White sucker population Phytoplanktons are an important part of ocean food chains. They are found in high productivity zones of an ocean. An increase in ocean temperature during specific times causes the death of phytoplanktons.

If all phytoplanktons die in the given food chain, then (A) All members of the food chain will continue to survive (B) Only zooplankton population will continue to survive (C) All members of the food chain will be affected (D) Only small fish population will be affected

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119 46.

47.

48.

49.

In the illustrated food web, direct transfer of energy occurs from the

(A) Small fishes to the killer whale (B) Small fishes to the krill (C) Seal to the killer whale (D) Krill to the seal A food chain depicts the flow of energy from one trophic level to another. Which of the following represents the percentage of energy transfer from one trophic level to the next? (A) 100% (B) 50% (C) 25% (D) 10% The given figure shows a tidal food web. The sedimented algae population decreases because of some disease, and the population of wading birds increases as a result of migration.

An immediate effect of the given situation will be (A) An increase in the population of shore birds (B) A decrease in ]population of shrimps (C) An increase in the population of worms (D) A decrease in the population of fishes The given pyramid shows a terrestrial food chain wherein 10,000 J of energy is present at the level of primary producers.

The amount of energy present at the level of mice is (A) 10,000 J (B) 1,000 J (C) 100 J

(D) 10 J

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6. ABIOTIC COMPONENTS The abiotic component of the environment is influenced by a number of factors. Temperature, light, water, air (oxygen and carbon dioxide), rocks, soil are all factors which influence the existence and survival of organisms. These factors are often called physical factors, constituting the physical environment of the organisms. TEMPERATURE The temperature is measured by a device called thermometer and is a measure of the degree of hotness. Most plants and animals grow well in warm places, but some need a cold climate. For example, polar bears and penguins are found in cold places. They cannot survive in warm (tropical) jungles. On the other hand, tigers and elephants live in warm jungles, and are not found in cold places. Pine trees are found in cold places such as the slopes of mountains or in cold (temperate) countries. Plants and animals growing in cold places may not be able to withstand the high temperatures of deserts. In India, cows and buffaloes are used for milk. Cows can tolerate hot weather whereas buffaloes cannot bear the summer heat. It is for this reason that you often see buffaloes cooling themselves in a pond, and not the cows. This adaptation to weather conditions is related to skin colour. Adaptations of Camel Camel, popularly known as "the ship of the desert", can tolerate high temperature of deserts. Camel has adapted, and developed mechanisms to live in hot weather. Some of these adaptations are given below: (i) It is capable of adjusting its body temperature to that of the surrounding desert habitat and thereby the water loss by perspiration and other means is drastically minimised. The human body temperature is 37 °C and if we are in a desert (where the temperature could be as high as 45 °C) we perspire a lot and it may even lead to dehydration of the body. This is because we have no ability to cope up with the high temperature of surroundings unlike camel. The camel copes with external high temperature by raising its own body temperature upto 42 °C. (ii) Camel can live without food or water at a stretch for as many as 10 days. When there is no water available to drink, it passes about half a litre of urine which is 10-20 times less than what is passes when water is available. (iii) When water is available, the animal can drink about 3 buckets of water (50 litres) at one time and this water in not stored in a particular part of its body but is evenly distributed all over the animal's body in tissues. Adaptations of cacti and opuntia Plants like cacti (Figure. 7.12) and opuntia have adapted to live in hot desert areas. The stem in these plants has become spongy, so as to store water. Leaves have been reduced to spines in order to reduce loss of water from the plant's surface. The function of the leaf has been taken over by the stem which has become green.

Figure 7.12: A cactus plant LIGHT Green plants need light to make food. They also need light to grow. They do not grow in dark places. In the absence of light, the leaves turn yellow. Animals such as earthworms, centipedes, millipedes do not like light. They move away from light. These animals are usually found in dark places such as under a log of wood, in a leaf litter or under the ground (inside the soil).

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The ultimate source of light and energy is the Sun. Flowers in Portuhca (dhoop khirri)plant bloom after sunrise and close down after sunset. Similarly, in Bauhinia (kachnar) leaves open during daytime and close or fold during night.

Figure 7.13: Temperature requirements of plants and animals WATER All living organisms need water for their sustenance. This life- sustaining natural resource covers 4/5th of the earth's surface. It makes up 60-70 per cent of our body weight. Water is required for growing crops, in industry and for human existence (drinking, cooking, cleaning etc.). Of the total water available in the country, 97 per cent is found in oceans (marine mm water) and only 3 per cent represents fresh water found in rivers, lakes and streams. Rain and snow are the principal sources of fresh water. Adaptations by water plants Cacti and camels are among the few plants and animals which can live in dry places like deserts. They have special water-storing organs in their bodies or other modifications as discussed above. Just as plants and animals have adapted to live in water-scarce areas, they have also developed mechanisms to exist in water only. Plants like water lily, Lemna and Eicchornia occur in water with floating leaves. Leaves in water lily are large and circular, floating on the surface of water (Figure 7.14). Also, a waxy waterproof coating is present which prevents their decay in water. In plants like Hydrilla, the leaves are present inside water. The leaves in such plants are long and thin (Figure 7.15) so that the strong water currents are not able to tear them apart.

Figure 7.14: Water lily

Figure 7.15: Hydrilla

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AIR Animals and plants require oxygen to stay alive. In the absence of oxygen, most organisms cannot respire and produce energy. As a result they die.

(a) Dandelion fruit with hair (b) Maple fruit with wings Figure 7.16: Adaptations in fruits Plants, in addition to oxygen, also require carbon dioxide to make food. This carbon dioxide is present in the air, and is produced by plants and animals during the process of respiration. The cycling of oxygen and carbon dioxide between the biotic and abiotic components is essential to keep their balance in nature. These days, this balance of gases in nature has been upset by the activities of humans. Carbon dioxide concentration in the atmosphere is going up, leading to an increase in temperature and thus warming of earth (global warming). This has very serious consequences for the existence of even our own race. This explains why we need to plant more and more trees. Air, when strong in the form of air currents, is called wind. Wind plays an important role in the dispersal of seeds and fruits. Seeds and fruits dispersed by wind are either very small and light or they possess certain adaptations like wings and hair (Figure. 7.16). Wind also helps in pollination. Wind-pollinated plants have developed mechanisms to ensure pollination by wind. As a large quantity of pollen grains are wasted, the plants produce sufficiently large quantity of small light pollen grains which can be easily blown by wind. Wind, however, causes the spread of harmful bacteria and spores of plants causing diseases and allergy. Strong winds also uproot trees, break branches and spread fires. In hilly areas, trees develop branches only on one side. In coastal areas, the leaves become deeply incised or serrated to reduce the effect of wind. This is what you observe in palm trees (Figure 7.17) like that of coconut found in coastal areas.

Figure 7.17: Leaves in a palm tree Wind also helps in the dispersal of pollutants. In the absence of wind, smoke forms a layer in the atmosphere. This is more pronounced during winters. This thick layer of smoke causes eye irritation, headache and other problems in human beings. Sometimes smog is formed when smoke mixes with fog. SOIL Without soil, most of the plants would not exist. And in the absence of plants, other forms of life would not exist. Soil consists of the following components: (1) Soil particles of different sizes (like stones or gravel, sand, silt, clay) - particle size in sand is bigger than silt and clay particles, but smaller than gravel.

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Organic matter or humus (3) Soil water (4) Soil air (5) Soil organisms. Organic matter (humus) provides fertility to the soil and is formed by the death and decay of plants and animals. The best soil for growing plants is one which is a mixture of clay, silt and sand. Such a soil is called a loam soil. Soil serves several functions - provides anchorage to the plants, provides water and nutrients to the plants, and allows soil organisms like earthworms, bacteria, insects and burrowing mammals to live inside it. For growing crops, man provides additional manures and fertilizers artificially to the soil, enriching its mineral content. 7. INTERDEPENDENCE AMONGST LIVING ORGANISMS All living things depend on other living things, directly or indirectly. For example, a deer needs grass to live, and a lion needs deer to live. In this example, a deer is directly dependent on grass, and the lion's dependence on grass is indirect. In a similar manner, all the plants, birds, reptiles, fish, insects, etc., are connected to each other, and depend, directly or indirectly, on each other. In other words, it also means that the survival of all the living things is dependent on each other. For a living thing to survive, it must exist in a certain proportion, and allow other living things to exist. Living things cannot afford to exist without any check. For instance, if there are too many lions, they will kill all the deer. On the other hand, if there are too many deer, they will eat too much grass, and not leave any grass for the other animals. Thus, different living organisms must exist to survive and allow others to survive. The result is a complete balance in nature. DEPENDENCE OF ANIMALS ON PLANTS Animals depend upon plants in various ways. 1. For Food: All animals depend for their food, directly or indirectly, on green plants (Figure. 7.18). 2. For Oxygen: Plants give out oxygen during the process of photosynthesis. The oxygen, so liberated, is used by animals and plants for their respiration. 3. For Shelter: Some animals depend on plants for shelter. They make their homes in holes in the trees. Some birds build their nests in the trees. Many insects like the grasshopper, moth, ants, beetle live in trees. Monkeys also live in trees.

Figure 7.18: Interdependence of Plants and Animals DEPENDENCE OF PLANTS ON ANIMALS 1. For Carbon dioxide. Plants need carbon dioxide to prepare food through photosynthesis. This carbon dioxide comes from animals during respiration (Figure 7.18). 2. For Pollination. In some plants, pollination is brought about by insects, birds and bats. Without pollination, formation of seeds in these plants would not be possible. 3. For Seed dispersal. Seed dispersal in many plants is through animals and even man. Fruits are eaten by animals such as the birds that carry them to distant places. Finally, the seeds are passed out in their excreta without any damage. Some seeds possess spines or hooks that enable them to stick to the body of animals and thereby help in their being carried from one place to the other. Finally man himself is a great disseminator of seeds, especially of those which he uses, for his food and other needs.

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DEPENDENCE OF HUMANS ON PLANTS AND ANIMALS

1.

FOR FOOD

124

(a) From plants (i) Cereals — Rice, wheat, maize, barley (ii) Pulses — Moong, gram, beans, arhar (iii) Vegetables — Onion, potato, spinach, brinjal, radish, carrot, beet root (iv) Fruits — Mango, apple, banana, grapes, pine-apple, orange (v) Beverages — Tea, coffee (vi) Sugar — Sugarcane (vii) Spices — Turmeric (haldi), pepper, chilli, clove (loung) (viii) Oil seeds — Groundnut, coconut, mustard (b) From animals (i) Milk — Cows, buffaloes, goats (ii) Eggs — Hen (iii) Meat or Fish — Goats, sheep, fish (iv) Honey — Honey bees 2.

FOR CLOTHING (a) (b)

3.

4. 5. 6. 7. 8. 9. 10.

From plants Fibres from cotton and jute From animals (i) Leather — Hide (skin) of buffaloes, sheep, rabbits and even snakes. (ii) Silk — Silk moth insects (cocoons) (iii) Wool — Fur of sheep

For Medicines — Most of the medicines are obtained from plants. (i) Penicillin — Fungus Penicillium (ii) Quinine — Bark of Cinchona (cure for malaria) For Timber or Wood (Furniture, housing, ship, etc.) Trees such as teak, sal, deodar. For Paper Wood pulp of bamboos and eucalyptus. For Rubber (For tyres, shoes, mattresses, etc.) Latex from rubber tree. For Perfumes, Dyes, Resins For Fuel For Ornamental and Landscape Purposes. A number of plants are grown in gardens and other places for aesthetic beauty. Other Uses (i) Plants prevent soil erosion by wind or water. (ii) Certain plants like legumes enrich soil fertility. (iii) A number of animals like horses, donkeys and bullocks are used for transportation, for ploughing fields, etc. (iv) Animals like dogs provide security to human beings.

9. ROLE OF HUMANS IN THE BALANCE IN NATURE: ECOLOGICAL CRISIS Some of the ways in which man's actions have upset the natural balance are as follows: 1. Indiscriminate felling of trees and clearing of forests (deforestation) has led to soil erosion and floods. Many animals have been rendered homeless by the destruction of forests. Availability of food has also been affected. As a result, many animals have moved from forests to areas inhabited by man, and have become man-eaters.

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Deforestation has also adversely affected the climate. Temperatures have risen, carbon dioxide concentration has increased, and rainfall has decreased. Hunting of animals has led to a disturbance in the food chains, thus upsetting the ecosystem. Killing of tigers on a large scale has increased the number of herbivores such as deer. These deer destroy the crops in turn. Population explosion and excessive industrialization have led to pollution of air, water and soil. Indiscriminate and excessive use of insecticides and pesticides like DDT (DDT does not undergo degradation) have led to their accumulation in the bodies of fish through water, and it ultimately reaches man. DDT being toxic may prove harmful in due course of time. In human beings DDT causes severe health problems. In birds, it prevents the formation of egg shell. As a result eggs break before they are hatched. Thus, man who uses DDT to protect his crops, is himself faced with destruction by the same chemical. The above-mentioned activities of man have brought about a crisis in the physical environment, that is, land, water and air.

2.

3. 4.

Formative Worksheet 54. 55. 56. 57. 58. 59. 60. 61.

62. 63.

64. 65.

Which of the following factors affect the abiotic components of environment? (A) Temperature (B) Light (C) Light (D) All Polar bears and penguins are found in (A) Hot places (B) cold places (C) Warm places (D) Deserts Pine trees are found in (A) Hot places (B) cold places (C) Warm places (D) Deserts The camel copes with external high temperature by raising its own body temperature upto (A) 42 °C (B) 84°C (C) 126 °C (D) 252 °C Which of the following plants are found in deserts? (A) Opuntia (B) Cacti (C) Rose (D) Tamarind Which of the following do not like light? (A) Earthworms (B) Centipedes (C) Millipedes (D) Housefly This life- sustaining natural resource covers ______of the earth's surface. (A) 1/2 (B) 3/4 (C) 4/5 (D) 1/3 Assertion (A): The leaves of hydrilla are long and thin. Reason (R): The strong water currents are not able to tear them apart. (A) A is correct and R is the correct explanation of A. (B) A is correct and R is not the correct explanation of (C) A is correct and R is wrong. (D) A is wrong and R is correct. (E) Both A and B are incorrect. Which of the following fruit has wings? (A) Dandelion (B) Maple (C) Mango (D) Apple Statement - I: Air, when strong in the form of air currents, is called wind. Statement – II: Wind plays an important role in the dispersal of seeds and fruits. (A) Statement - I is true, Statement - II is false.(B) Statement - I is false, Statement - II is true. (C) Both statements are true. (D) Both statements are false. Animals depend upon plants for (A) Food (B) Oxygen (C) Shelter (D) All Match the following Column-I Column-II 1. Cereals p. Mango, apple, banana, grapes, pine-apple, orange 2. Pulses q. Onion, potato, spinach, brinjal, radish, carrot, beet root 3. Vegetables r. Moong, gram, beans, arhar 4. Fruits s. Rice, wheat, maize, barley (A) 1234/pqrs (B) 1234/spqr (C) 1234/srqp (D) 1234/psrq

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Our Environment 66.

Match the following Column-I 1. Penicillin 2. Quinine 3. Timber 4. Paper (A) 1234/pqrs

126

Column-II p. Bark of Cinchona q. Teak r. bamboos and eucalyptus s. Fungus Penicillium (B) 1234/spqr (C) 1234/srqp

(D) 1234/psqr

Conceptive Worksheet 50.

Statement - I: The temperature is measured by a device called manometer. Statement – II: The degree of hotness or coldness of a body is called temperature. (A) Statement - I is true, Statement - II is false.(B) Statement - I is false, Statement - II is true. (C) Both statements are true. (D) Both statements are false. 51. Tigers and elephants are found in (A) Antartica (B) Cold places (C) Warm jungles (D) Deserts 52. Which of the following is called ‘ship of the desert’? (A) Tiger (B) Lion (C) Elephant (D) Camel 53. Camel can live without food or water at a stretch for as many as (A) 20 days (B) 15 days (C) 10 days (D) 5 days 54. Assertion (A): Leaves of desert plants have been reduced to spines Reason (R): This is to reduce loss of water from the plant's surface (A) A is correct and R is the correct explanation of A. (B) A is correct and R is not the correct explanation of (C) A is correct and R is wrong. (D) A is wrong and R is correct. (E) Both A and B are incorrect. 55. Which of the plant’s Flowers bloom after sunrise and close down after sunset? (A) Rose (B) Jasmine (C) Portuhca (D) Chrysanthemum 56. Which of the following plant has floating leaves? (A) Lemna (B) Eicchornia (C) Opuntia (D) Asparagus 57. Which of the following fruit has hairs? (A) Dandelion (B) Maple (C) Mango (D) Apple 58. The increase in carbon dioxide level in atmosphere leads to (A) Air pollution (B) Water pollution (C) Global warming (D) Land pollution 59. Smog is a mixture of fog and (A) Smoke (B) Water (C) Air (D) None 60. Plants depend on animals for (A) Carbon dioxide (B) Pollination (C) Seed dispersal (D) All 61. Match the following Column-I Column-II 1. Beverages p. Tea, coffee 2. Sugar q. Turmeric (haldi), pepper, chilli, clove (loung) 3. Spices r. Groundnut, coconut, mustard 4. Oil seeds s. Sugarcane (A) 1234/pqrs (B) 1234/spqr (C) 1234/srqp (D) 1234/psqr 10. POLLUTION Pollution is nothing but an undesirable change in the natural quality of the environment that may adversely affect man and other living beings. The agents which cause pollution are called pollutants. Man is mainly responsible for pollution. TYPES OF POLLUTION There are five major types of pollution: 1. Air pollution 2. Water pollution 4. Noise or sound pollution 5. Radioactive pollution

3. Land or soil pollution

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127

6th Biology

Pollutants, on the basis of their nature, can be of two types: 1. Bio-degradable 2. Non-biodegradable. Bio-degradable pollutants are those which get decomposed by the activity of micro- organisms. So, if used within limits, pollution is avoided. Example : Organic matter like manure, garbage Non-biodegradable pollutants, on the other hand, do not decompose and thus accumulate in the atmosphere. Finally, these pollutants reach the body of living organisms through the food chain causing immense harm and even death. Examples : DDT, plastics, lead, mercury. AIR POLLUTION Air pollution is the contamination of air with smoke, dust and harmful gases. These contaminants are the pollutants of air. Causes 1. Excessive burning of fossil fuels like coal, kerosene, petrol and diesel. 2. Smoke from vehicles. 3. Smoke from factories and thermal power stations. 4. Deforestation (cutting down of trees). Effects 1. Disorders of the respiratory system (bronchitis and asthma). 2. Irritation in the eyes, nose and throat. Control Measures 1. Use of smokeless fuels to be encouraged and that of fossil fuels to be avoided. 2. Growing trees (afforestation) to purify air. 3. Installation of tall chimneys with filters in factories so that their emissions are given out high up in the atmosphere. WATER POLLUTION Water pollution is the contamination of water with pollutants like sewage, industrial wastes and other harmful materials. Causes 1. Discharge of sewage and detergents into lakes and rivers. 2. Human activities like bathing and washing of clothes. 3. Discharge of industrial wastes, fertilizers and pesticides. 4. Defecation by humans and animals in or near water sources. 5. Oil spills from oil tankers. Effects 1. Serious water-borne diseases like typhoid, cholera, jaundice and dysentery in humans. 2. Aquatic plant and animal life is damaged or killed. Control Measures 1. Sewage treatment — by physical and chemical means. 2. Recycling of industrial wastes. 3. Use of biological fertilizers and pesticides. 4. Provision for proper sanitary and hygienic conditions. LAND/SOIL POLLUTION Contamination of the land or soil with wastes like garbage, fertilizers, pesticides, metals and plastics is called land or soil pollution. Causes 1. Improper disposal of garbage, glass bottles, plastics, metals, paper, medical wastes (syringes, cotton), etc. 2. Excessive use of fertilizers, pesticides and insecticides to increase crop yield. 3. Dumping of radioactive wastes. www.bemedicos.com ____________________________________________________________________________________________________

Our Environment

128

Effects 1. Useful soil micro-organisms are destroyed. 2. Plant growth is affected. Control Measures 1. Proper disposal of garbage, away from residential areas. 2. Converting biodegradable wastes into useful products. 3. Excessive use of artificial fertilizers, pesticides and insecticides to be avoided; the use of natural alternatives which are biodegradable to be encouraged. 4. Use of plastics to be banned. 5. Recycling technologies to be used. SOUND/NOISE POLLUTION Prolonged loud noise from different sources is called sound or noise pollution; it causes mental and physical harm. Causes 1. Use of pressure horns; blaring of bands and loudspeakers during marriages and festivals 2. Radio, television 3. Bursting of crackers 4. Cars, motorcycles, aeroplanes Effects 1. Damage to ears; may cause partial deafness. 2. Sleeplessness 3. Affects nervous system and causes mental depression Control Measures 1. Ban on the use of high volume loudspeakers and excessive use of horns. 2. Ban on crackers 3. Putting a legal ban 4. Initiating public awareness compaigns. In brief, it must be realised that man and nature need each other, and by hurting one, we wound the other. So, conserve and preserve Nature. GENERAL MEASURES TO CHECK POLLUTION 1. Do not cut trees, rather plant trees. 2. Do not destroy flora (plants) and fauna (animals), to maintain the proper ecological balance. 3. Use bio-degradable substances, as far as possible. 4. Solid waste materials should not be thrown in water or in your surroundings. These materials should be properly disposed off. 5. Waste materials should be recycled. Recycled paper is a step in this direction. 6. Use of solar cookers and biogas should be encouraged. This would reduce the pressure on the burning of fossil fuels like coal. 7. Strict check on the emissions from automobile exhausts should be enforced. 8. Industries should be made to strictly adhere to the anti-pollution steps, laid down by the government. 9. Chimneys of the industries should be very tall, so that their emissions are given out high up in the atmosphere. 10. Industries should not be located in residential areas.

Formative Worksheet 67.

68.

An undesirable change in the natural quality of the environment that may adversely affect man and other living beings is called (A) Global warming (B) Pollution (C) Green house effect (D) None Which of the following are non bio-degradable pollutants? (A) Manure (B) Garbage (C) DDT (D) Plastics

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6th Biology

129 69. 70.

71.

72. 73. 74.

75. 76.

77. 78.

79. 80.

Which of the following are air pollutants? (A) Smoke (B) Dust (C) Sulphur dioxide (D) All Which of the following leads to air pollution? (A) Smoke from vehicles (B) Smoke from factories and thermal power stations (C) Deforestation (D) All Which of the following controls air pollution? (A) Smoke from vehicles (B) Smoke from factories and thermal power stations (C) Deforestation (D) Growing trees Discharge of sewage and detergents into lakes and rivers leads to (A) Air pollution (B) Water pollution (C) Land pollution (D) All Cholera and typhoid are caused due to (A) Air pollution (B) Water pollution (C) Land pollution (D) All Which of the following controls water pollution? (A) Sewage treatment (B) Recycling of industrial wastes (C) Use of biological fertilizers and pesticides (D) Proper sanitary and hygienic conditions Excessive use of fertilizers, pesticides and insecticides to increase crop yield leads to (A) Air pollution (B) Water pollution (C) Land pollution (D) All Land pollution leads to (A) Destruction of soil micro-organisms (B) Plant growth is affected (C) Both (D) None Prolonged loud noise from different sources leads to (A) Air pollution (B) Land pollution (C) Sound pollution (D) All Which of the following leads to land pollution? (A) Radio, television (B) Bursting of crackers (C) Cars, motorcycles (D) All Partial deafness is caused due to (A) Air pollution (B) Land pollution (C) Sound pollution (D) All Which of the following is caused due to noise pollution? (A) Sleeplessness (B) Asthma (C) Dysentery (D) All

Conceptive Worksheet 62. 63. 64. 65. 66. 67.

68.

Which of the following are bio-degradable pollutants? (A) Manure (B) Garbage (C) DDT Lead is a _____ pollutant. (A) Biodegradable (B) Non-biodegradable (C) Both Excessive burning of fossil fuels like coal, kerosene, petrol and diesel leads to (A) Air pollution (B) Water pollution (C) Land pollution Bronchitis and asthma are caused due to (A) Air pollution (B) Water pollution (C) Land pollution Which of the following are water pollutants? (A) Sewage (B) Industrial wastes (C) Both Which of the following leads to water pollution? (A) Bathing and washing of clothes in rivers or ponds (B) Discharge of industrial wastes, fertilizers and pesticides into water (C) Oil spills from oil tankers (D) All Which of the following is caused due to water pollution (A) Bronchitis (B) Asthma (C) Jaundice

(D) Plastics (D) None (D) All (D) All (D) None

(D) Dysentery

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Our Environment

130

69.

Which of the following are land pollutants? (A) Garbage (B) Fertilizers (C) Pesticides (D) All 70. Which of the following leads to land pollution? (A) Improper disposal of garbage, glass bottles (B) Dumping of radioactive wastes (C) Converting biodegradable wastes into useful products (D) Banning of use of plastics 71. Which of the following controls land pollution? (A) Proper disposal of garbage, away from residential areas. (B) Converting biodegradable wastes into useful products. (C) Banning of use of plastics (D) All 72. Which of the following controls noise pollution? (A) Ban on the use of high volume loudspeakers and excessive use of horns. (B) Burning of crackers (C) Initiating public awareness campaigns (D) Use of pressure horns SNAP SHOT 1. Earth is a unique planet in the solar system, as it has features which permit life to exist on this planet. 2. Earth consists of lithosphere, hydrosphere and atmosphere. 3. Environment comprises living and non-living components which interact with one another. 4. The part of the Earth where living organisms are found is called the biosphere. 5. There is a close interaction of the living organisms (biotic component) with the non-living environment (abiotic component). The biotic and the abiotic components together constitute an ecosystem. 6. In addition, there is a third component of the environment — the cultural component which consists of the human influences on the environment. 7. The biotic component consists of producers (plants), consumers (herbivores and carnivores) and decomposers (micro-organisms like bacteria and fungi). 8. Plants are called producers as they prepare their own food by photosynthesis. 9. Animals are called consumers as they depend on others for food. 10. The abiotic component comprises mainly of air, water and soil. 11. Food relationships exist between the organisms, in the form of food chains and food webs. 12. In the biotic component, energy flow starts from the sun -> producers -» herbivores -» consumers. 13. The physical abiotic factors influence the distribution of plants and animals. 14. Man has upset the natural environment. The man-made environment is termed socio-cultural environment. 15. In nature, survival of living things is dependent on each other. There exists a complete balance in nature between the living things. Human beings, however, have upset this balance for their growing personal needs and desire to possess more and more by deforestation (feeling of trees), hunting (killing animals), overpopulation and excessive industrialization. Thise activities have led to pollution of air, land and water. 16. There is an urgent need to conserve and preserve NATURE.

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131

Summative Worksheet I. 1.

2.

3.

4.

5.

6.

Multiple choice questions. The atmosphere consists of (A) Troposphere, stratosphere, ionosphere (B) Biosphere, geosphere, lithosphere (C) Only biosphere (D) Only geosphere The gas in the atmosphere which prevents harmful ultraviolet rays from reaching the earth is (A) Carbon dioxide (B) Ozone (C) Oxygen (D) Carbon monoxide The part of the Earth where like exists is called (A) Atmosphere (B) Hydrosphere (C) Biosphere (D) Lithosphere The biotic components of the environment are (A) Producers (B) Carnivores (C) Herbivores (D) All the above Vultures play the role of ___________ in the environment. (A) Herbivoures (B) Scavengers (C) Carnivores (D) Decomposers Increase in concentration of ___________ gas has led to global warming. (A) Ozone (B) Sulphur dioxide (C) Nitrogen (D) Carbon dioxide

II. 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.

Fill in the blanks: The two major components of environment are ___________ and ___________. The process of 'eating and being eaten' is termed as ___________. Animals that feed on dead flesh are called ___________. Organisms which feed on dead and decaying bodies are called ___________ Interlinked food chains constitute a ___________ The food chain consists of producers and ___________. Bacteria and fungi act as ___________ in the environment. The primary source of energy for all living organisms is the ___________. Plastic bags cannot be recycled because they are ___________. Vegetables, leaves and fruits are easily decomposed because they are ___________. Three examples of scavengers in the environment are ___________,and ___________.

III. 1. 2. 3. 4. 5. IV. 1. 2. 3. 4. 5.

Which of the following statements are true (T) and which ones are false (F)? Mark T or F. Green plants respire by taking in both carbon dioxide and oxygen. The ultimate source of energy for all organisms is the green plant. The interaction of living organisms with the non-living environment constitutes the ecosystem. The survival of all living things is dependent on each other. Organisms which feed on dead and decaying bodies are called scavengers. Give differences between the following: Environment and Surroundings Food chain and Food Web Producers and Consumers Herbivores and Carnivores Decomposers and Scavengers.

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Our Environment

V.

VI. 1. 2.

3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20.

Define the following terms: 1. Ecology 2. Ecosystem 4. Energy flow 5. Scavengers 7. Community 8. Food chain.

132

3. Environmental factors 6. Population

Answer the following questions: Name the different kinds of living organisms which exist in our environment. How are the following adapted to live in their respective environment? (i) A cactus plant (ii) Camel (iii) Water lily (iv) Hydrilla (v) Palms Name two biodegradable materials. Name one non-biodegradable material. Name two scavengers. Name the raw materials used by plants to manufacture their food. Which gas is released during the process of photosynthesis? How have the socio-cultural activities influenced our environment? Write on the cultural component of the environment. Write in brief about the components of the environment. Write the brief about the abiotic components of the environment? Give examples of three food chains operating in nature. Why are plants called producers? What is meant by a food web? Explain with the help of a simple diagram. What would happen if any of the links is missing in the food chain? “Life would be impossible without plants”. Explain. Explain the importance of recycling in the environment. Mention the role played by the decomposers in an ecosystem. Justify the statement ‘No living organism can live by itself’. Name three pollutants each of air, water and soil.

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1.LIFE ON EARTH FORMATIVE WORKSHEET Q.No Key Q.No Key Q.No Key Q.No Key

1 A 11 A 21 C 31 A

2 B 12 C 22 D 32 ABCD

3 D 13 A 23 D 33 B

4 D 14 A 24 D 34 D

5 A 15 D 25 D 35 C

6 C 16 C 26 D 36 A

7 A 17 D 27 D 37 D

8 A 18 C 28 D 38 D

9 B 19 C 29 D 39 B

10 C 20 C 30 D 40 D

CONCEPTIVE WORKSHEET 1.

(a)

All these things possess mass, shape and occupy space.

(b)

Both the living and the non-living things have a structural unit - cells in the living and molecules in the non-living things.

(c)

Cells do not exist in non-living things.

2.

Amoeba, yeast, and bacteria are unicellular organisms. mango plant, rose plant, pea plant, man, housefly, dog and cat are multicellular organisms.

3.

This is absorbed from the atmosphere (air) by the leaves through minute pores (called stomata) present on their surface

4.

The green plants utilize (i) carbon dioxide from air, (ii) water and minerals from soil, and (iii) sunlight to prepare their food.

5.

Organisms that can prepare their own food material are called autotrophs and the mode of nutrition is called autotrophic nutrition. Organisms that depend on other organisms like plants and animals for their food are called heterotrophs. And the mod of nutrition is called heterotrophic nutrition.

6.

(i) Response: A response is an activity in the living body that results from a stimulus. (ii) Stimulus: Anything which produces a response in an organism is called stimulus. (iii) Phototrophic: Bending of plant towards sunlight is called phototrophic movement. (iv) Geotrophic: Growth of roots downward into the soil is called geotropic movement.

7.

(i) Urine, sweat and carbon dioxide (ii) Carbon dioxide and water vapour

8.

Growth, if present, in non-living things is external as it takes place by adding matter externally and it is reversible. Growth in living things takes place by the addition of new body material called protoplasm, and is thus internal.

9.

Only living things reproduce i.e., they have the ability to produce their young ones. Hence, cat, mango tree and rose plant have ability to reproduce.

10.

In animals, the life cycle consists of birth, growth, reproduction and death. The period during which an organism completes its life cycle is called its life span.

Key

134

11.

3. Respiration

Living Things Are made up of cells. Require food for growth and development. Show respiration.

4. Growth

Is permanent and irreversible.

1. Cellular Organisation 2. Nutrition

5. Excretion 6. Reproduction 7. Response to stimuli (responsiveness) 8. Life cycle

Non-living Things Lack cellular organisation. Not required. No respiration. Lack growth; even if present it is reversible.

Removal of waste materials takes place. Takes place.

No excretion. No reproduction.

Present.

Absent.

Consists of birth, growth, reproduction and death.

Lack a life cycle.

12.

The organisms are that are very small and cannot be seen with naked eye are called micro organisms. Bacteria, some fungi (like yeast, Aspergillus, Penicillium), some algae (like Chlamydomonas, Oscillatoria, diatoms), and some protozoans (like Amoeba, Plasmodium).

13.

With the help of a microscope.

14.

Plants, being fixed to the soil, do not move from place to place. They lack organs for locomotion. Some plants, too, can move, but only very slowly. Daisies and other flowers move their petals when they close them at night and open them in the morning. Leaves of some plants like touch-me-not suddenly curl up on being touched.

15. Plants

Animals

Nutrition : Most plants can manufacture their own food (they contain a green pigment called chlorophyll) — autotrophic in nutrition.

Animals cannot make their own food (lack chlorophyll) — heterotrophic in nutrition.

Locomotion: They are generally fixed to the soil; lack organs for locomotion.

Show locomotion; possess organs for locomotion.

Growth: Growth is unlimited and localised.

Growth is limited and diffused.

Cell structure: Possess a cell wall; chloroplasts are present.

Lack a cell wall; chloroplasts are lacking.

SUMMATIVE WORKSHEET Multiple choice questions. Q.No Key

1 D

2 A

3 C

4 B

5 B

Fill in the blanks 1. Biology 2. 3. Unicellular organisms 4. 5. Respiration 6. 7. Respiration 8. Write true or false in front of the statements given below: 1. False 2. False 3. False

Cell Cells Sponges and Seanemones Chlorophyll

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6th Biology

135

2.CLASSIFICATION OF LIVING BEINGS FORMATIVE WORKSHEET Q.No Key Q.No Key Q.No Key Q.No Key Q.No Key Q.No Key

1 B 11 A 21 CD 31 B 41 A 51 D

2 C 12 C 22 C 32 C 42 C 52 D

3 C 13 ABCD 23 D 33 D 43 C 53 B

4 A 14 B 24 D 34 D 44 D 54 A

5 B 15 D 25 D 35 C 45 C 55 BC

6 D 16 C 26 C 36 C 46 C 56 B

7 B 17 B 27 C 37 D 47 D 57 B

8 A 18 C 28 B 38 D 48 C 58 C

9 D 19 D 29 D 39 C 49 A

10 A 20 B 30 C 40 B 50 D

17 D 17 D 27 D 37 A

18 D 18 B 28 D 38 C

19 D 19 D 29 D 39 C

20 ABC 20 C 30 C 40 D

7 B

8 A

9 A

10 A

CONCEPTIVE WORKSHEET Q.No Key Q.No Key Q.No Key Q.No Key Q.No

11 D 11 A 21 D 31 D 41 A

12 C 12 D 22 A 32 A 42 D

13 A 13 B 23 B 33 C 43 A

14 C 14 A 24 A 34 B 44 A

15 C 15 ABCD 25 A 35 A 45 B

16 D 16 C 26 B 36 B 46 D

SUMMATIVE WORKSHEET Multiple choice questions. Q.No Key Q.No Key

1 B 11 D

2 C 12 B

3 C 13 B

4 B 14 A

5 A

6 A

Fill in the blanks: 1. Algae 2. Amoeba 3. Carolus Linnaeus 4. frog 5. Bird 6. Arthropoda 7. Amphibia 8. Starfish 9. Algae 10. Fungi Find the odd-one out. Give reasons. 1. Chlamydomonas. 2. Bacteria. 3. Chlamydomonas. 4. Cycas 5. earthworm. 6. crab. 7. crocodile. 8. Snake Which of the following statements are true (T) and which ones are false (F)? Mark T or F. (i) F (ii) F (iii) T (iv) T (v) F (vi) F (vii) F ______________________________________________________________________________________________________________________________

Key

136

3.SOIL FORMATIVE WORKSHEET

1. 2. 3. 4. 5. 6. 14. (a) (b) (c) (d)

Q.No Key

1 *

2 *

3 *

4 *

5 *

6 *

7 A

8 D

9 A

10 B

Q.No

11

12

13

14

15

16

17

18

19

20

Key Q.No Key

C 21 B

B 22 C

D 23 C

* 24 D

* 25 A

C 26 B

A 27 B

C 28 D

C

A

(a) slow (b) physical and chemical weathering (a) humus (b) Top soil (a) Physical (b) Texture (a) Clayey (b)Lime (a) Terrace (b) Conservation (a) deforestation (b) Organic

(c) Physical

Soil is the uppermost layer of the Earth’s crust and is usually composed of a thin layer of mineral particles, A layer of dead and decayed plant and animal remains called humus. A vertical section that shows the distinct layers of soil or horizons when we cut straight down into the soil is known as a soil profile. Weathering is the disintegration of rocks on the Earth’s surface caused by exposure to natural forces such as wind, water, frost, roots of plants, etc.

15. Sandy soil More than two thirds of  sandy soil is sand, and about one-tenth is clay

Clayey soil More than two-thirds of  clayey soil is clay.

Loamy soil Loamy soil has sand and silt in equal amount, about two-fifth each. One-fifth of loamy soil is clay.



It is made up of large  particles with large air spaces

It has high humus content



The porosity of the soil  prevents retention of water.



It is well suited for fruit  and vegetable cultivation

It is made up of fine  particles with small air spaces  This soil retains moisture and becomes very sticky when wet  Dry clayey soil becomes hard and forms deep cracks. To improve this soil, chalk can be added



It is porous and also holds moisture

It is good for cultivation of crops and gardening

CONCEPTIVE WORKSHEET Q.No Key

1 B

2 A

3 C

4 A

5 B

6 A

Q.No

11

12

13

14

15

16

Key

D

C

C

C

C

C

7 B

8 D

9 A

10 A

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6th Biology

137 SUMMATIVE WORKSHEET Multiple choice questions. Q.No 1 2 3 4 5 Key B C D A A Write true or false in front of the statements given below (i) T (ii) F (iii) T (iv) (v) T (vi) T (vii) T (viii) Fill in the blanks: 1. less than 0.002 mm 2. ‘A’ horizon or top soil 3. top soil 4. ‘C’ horizon 5. Afforestation 6. iron oxides 7. A horizon or top soil

T F

4.FOSSILS FORMATIVE WORKSHEET Q.No Key Q.No Key

1 C 11 A

2 C 12 D

3 C 13 B

4 D 14 B

5 B 15 A

6 C 16 B

7 B

8 B

9 B

10 D

7 A

8 B

9 D

10 B

CONCEPTIVE WORKSHEET Q.No Key Q.No Key

1 A 11 B

2 B 12 D

3 B 13 A

4 A 14 A

5 B 15 A

6 D

SUMMATIVE WORKSHEET Multiple choice questions. 1.

C

2.

B

Fill in the blanks: 1. 2. 3.

Sedimentary Coal, petroleum, natural gas non renewable

5. STRUCTURE AND FUNCTIONS OF PLANT PARTS FORMATIVE WORKSHEET Q.No Key Q.No Key Q.No Key Q.No Key Q.No Key Q.No Key Q.No Key

1 B 11 D 21 B 31 A 41 C 51 D 61 D

2 C 12 D 22 C 32 A 42 A 52 C 62 D

3 D 13 B 23 C 33 B 43 B 53 D 63 B

4 C 14 C 24 B 34 A 44 A 54 C 64 D

5 C 15 A 25 D 35 C 45 B 55 D 65 B

6 B 16 D 26 B 36 C 46 A 56 B

7 A 17 A 27 A 37 D 47 B 57 A

8 D 18 B 28 A 38 B 48 A 58 D

9 C 19 A 29 D 39 A 49 C 59 B

10 A 20 A 30 D 40 C 50 A 60 C

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Key

138 CONCEPTIVE WORKSHEET Q.No Key Q.No Key Q.No Key Q.No Key Q.No Key Q.No Key

1 C 11 A 21 B 31 D 41 C 51 B

2 B 12 A 22 A 32 A 42 D 52 A

3 C 13 A 23 D 33 A 43 B 53 C

4 A 14 A 24 C 34 A 44 D 54 B

5 C 15 D 25 C 35 B 45 D

6 A 16 ABCD 26 B 36 B 46 A

7 B 17 D 27 D 37 D 47 A

8 D 18 C 28 D 38 D 48 B

9 A 19 A 29 A 39 C 49 B

10 BC 20 A 30 C 40 C 50 B

7 C

8 C

9 A

10 B

SUMMATIVE WORKSHEET Multiple choice questions. Q.No Key

1 C

2 B

3 B

4 D

5 A

6 A

Fill in the blanks: 1.

Mustard Other answers: gram, pea, balsam, tulsi, marigold, rose, oleander, mango and neem,

2.

Wheat Other answers: maize, millets, other grasses, sugarcane and banana

3.

stem

4.

stem

5.

spines

6.

chlorophyll

7.

Support

8.

roots

9.

leaves

10.

Node

11.

photosynthesis

12.

radical

13.

Stomata

14.

Calyx, corolla, stamen and carpel

15.

Anthers

16.

Seeds, Fruits

17.

Stamens

18.

Pollination

19.

Ovules

20.

shoot system, root system

Which of the following statements are true (T) and which ones are false (F)? Mark T or F 1. True 2. False 3. False 4. True 5. False 6. True 7. True 8. True 9. True 10. False 11. False 12. False 13. True 14. True Match the items in Column A with those in Column B : 1. a – v, b – vii, c – ix, d –i , e-vi – f– viii, g – iv, h – x, i –ii , j – iii Find the odd one out, giving reasons. 1. 2. 3. 4. 5.

root. tendrils. root. self pollination filament.

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6th Biology

139

6. HEALTH AND HYGIENE FORMATIVE WORKSHEET Q.No Key Q.No Key Q.No Key Q.No Key

1 B 11 D 21 D 31 D

2 B 12 C 22 A 32 B

3 C 13 D 23 A 33 A

4 B 14 D 24 D 34 A

5 B 15 B 25 C 35 B

6 D 16 A 26 B 36 D

7 D 17 B 27 ACD 37 D

8 A 18 D 28 C 38 B

9 C 19 C 29 B 39 CD

10 D 20 A 30 B 40 AB

7 C 17 B 27 C

8 D 18 CD 28 B

9 D 19 B 29 C

10 D 20 * 30 C

5 A

6 B

9 B 19 C 29 B

10 D 20 D 30 A

CONCEPTIVE WORKSHEET Q.No Key Q.No Key Q.No Key Q.No Key

1 D 11 D 21 D 31 D

2 A 12 D 22 D

3 CD 13 AC 23 A

4 C 14 A 24 D

5 B 15 B 25 C

6 BD 16 D 26 AB

SUMMATIVE WORKSHEET Multiple choice questions. Q.No Key

1 A

2 A

3 B

4 C

Fill in the blanks: 1. 4. 6.

proteins balanced diet eyes

2. 5.

Fats 3. Balanced carbohydrates, fats and proteins

III. Find the odd one out, giving reasons. 1. coconut oil 2. Groundnut 4. anaemia Classify the following habits as good or bad: 1. good 2. Bad 4. good 5. Bad

3.

cheese

3. 6.

good good

7. OUR ENVIRONMENT FORMATIVE WORK SHEET Q.No Key Q.No Key Q.No Key

1 C 11 A 21 C

2 A 12 AB 22 C

3 A 13 D 23 A

4 B 14 D 24 C

5 B 15 C 25 A

6 A 16 A 26 B

7 B 17 C 27 A

8 AB 18 B 28 A

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Key

140 Q.No Key Q.No Key Q.No Key Q.No Key Q.No Key

31 B 41 D 51 C 61 A 71 D

32 A 42 D 52 A 62 B 72 B

33 A 43 C 53 D 63 C 73 B

34 B 44 B 54 D 64 D 74 ABCD

35 B 45 D 55 B 65 C 75 C

36 D 46 A 56 B 66 B 76 C

37 B 47 A 57 A 67 B 77 C

38 D 48 D 58 AB 68 CD 78 D

39 D 49 A 59 ABC 69 D 79 C

40 B 50 D 60 C 70 D 80 A

7 C 17 C 27 D 37 A 47 D 57 A 67 D

8 C 18 B 28 A 38 D 48 D 58 C 68 CD

9 A 19 A 29 B 39 D 49 C 59 A 69 D

10 C 20 C 30 A 40 B 50 B 60 D 70 AB

5 B

6 D

CONCEPTIVE WORK SHEET Q.No Key Q.No Key Q.No Key Q.No Key Q.No Key Q.No Key Q.No Key Q.No Key

1 B 11 C 21 D 31 B 41 D 51 C 61 D 71 D

2 A 12 B 22 B 32 C 42 B 52 D 62 AB 72 AC

3 C 13 D 23 D 33 A 43 B 53 C 63 B

4 C 14 D 24 C 34 B 44 B 54 A 64 A

5 C 15 D 25 B 35 C 45 C 55 C 65 A

6 D 16 A 26 A 36 C 46 C 56 AB 66 C

SUMMATIVE WORKSHEET Multiple choice questions. Q.No Key

1 A

2 B

3 A

4 D

Fill in the blanks: 1.

biotic and abiotic 2.

food chain

3.

scavengers

4.

decomposers

5.

food web

6.

consumers

7.

decomposers

8.

Sun

9.

non-biodegradable

10.

biodegradable

11.

Hawk, crows, jackals, vultures

Which of the following statements are true (T) and which ones are false (F)? 1. 4.

True True

2. 5.

False False

3.

True

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