1.ECOLOGY – The study of the interaction of living organisms with each other and their surrounding is called ecology.

2.ENVIRONMENT –Everything that surrounds organisms and influences its life.

a)      Biotic components of environment – The living organisms e.g. Plants and animals.

b)      Abiotic components of environment –the nonliving components like air, light, etc.

3.ECOSYSTEM – All interacting organism in area =together with the nonliving constituents of environment. ( Functional unit of an environment)

4.PRODUCERS – They make the energy from sunlight available to the rest of the ecosystem.

5.CONSUMERS – Animals cannot manufacture their own food. They are called consumers.

6.BIODEGRABLE – Substances that are broken down by the action of bacteria or saprophytes. e. g. Paper.

7.NONBIODEGRABLE– Substances that are not broken down by the action of bacteria or saprophytes. e.g. Plastic.

8.FOOD CHAIN – The process of one organism eating the other.


9.FOODWEB — It is a network of food links between populations in a community.

10.10% LAW OF ENERGY FLOW – The energy available at any trophic level in a food chain is 10% of the previous one.

11.BIOLOGICAL MAGNIFICATION – Progressive accumulation of nonbiodegradable waste at various trophic levels of food chain. HIGHER ORDER THINKIN SKIILS (HOTS) QUESTIONS

1. Write any two ways of energy flow through an ecosystem.

2. Differentiate between biodegradable and non biodegradable with respect to the effect of biological processes on them and the way they affect our environment.

3. Which level shows the maximum biological magnification? Why?

4. Why is pond self-sustaining unit while an aquarium may not be? Justify the answer.

5. Arrange grasshopper, frog, grass, eagle and snake in the form of food chain.

6. If 1000 KJ energy is available at producer level, how much energy will be available at first carnival level?

7. Why do most food chains have 3-5 steps only?

8. Select the biodegradable items from the list given blow-

Polythene bags, old clothes, wilted flowers, pencil shavings, glass bangles, bronze statue, vegetable peels.

9. What will be impact on ecosystem if bacteria and fungi are removed from the Environment?

10. Express your feelings on the picture given down below. What will happen if all?

Carnivores are eliminated from the environment? What measures will you take to save? Tiger?


Very short answer questions:

NOTE: Each question carries one mark.


1.      Ozone layer is destroyed by

a)      SO2                       b) Smog                 c) CFC                                    d) CO2

2.      Which of the following is biodegradable?

a)      Cow dung             b) Plastic                     c) DDT            d) Radioactive wastes

3.      Vegetables peels, waste paper, wood carvings and egg shells can be used to make

a)      Bricks                    b) Compost                 c) Urea                        d) None of these

4.      Which of the following is constituent of food chain?

a)      Grass, wheat and mango                     b) Grass, goat and human

c) Goat, cow and elephant                        d) Grass, fish and goat

5. Acid rain is caused by precipitation of

a)      Oxides of sulphur       b) CFCs           c)  Ozone                     d) CO2



1)      Classify the flowing as decomposers and producers Green plants, bacteria, fungi, algae, blue green algae.

2)      Distinguish between producers and consumers.

3)      Name two environment friendly practices.



  1. How is ozone depletion caused? Name the compounds causing it.
  2. What is meant by biodegradable waste? Which of the following are biodegradable? Agriculture residue, plastic, insecticides, sewage.
  3. What is being done to avoid ozone depletion? ( Three steps)
  4. What is meant by a trophic level? Why do we have a greater number of organisms at lower levels?

Long answer (5 marks)

5.   Describe any five modes of disposal of wastes.



  1. Ozone layer is destroyed by ­­­­­­­­­­­­­­­­­__________________.
  2. Ecology is the study of the interaction of _______ with each other and their surroundings.
  3. Decomposers are also called ________________.
  4. Water, air, light and temperature are the examples of _______components.
  5. Consumers ________ manufacture their own food and depend on plants and other animals for their feed.
  • Seminar: Children discuss ways and  means to reduce the problems given below:

a)      Ozone depletion                             b) Garbage disposal

  • Symposium:

Environment problems: Groups mention the problems they are facing in day today life.

  • Group discussion

Role of students in bringing awareness among community members on ill effects of polythene bags.

  • Activities:

a)      To study the ill effects of using some chemical like CFCS, nitrogenous fertilizers, DDT etc.

b)      Field trips: Visit to a botanical garden.

1.Role play of food chain and food web by class students.

2.Skit /Action Song on Banning of plastics.

3.Write a passage on ‘Autobiography of plastics.

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