Practise Class 8 Science Chapter 12 – How Nature Works in Harmony with this easy NCERT Curiosity worksheet. Includes important questions and revision exercises to strengthen understanding of ecosystems, nature and interactions among living organisms and prepare effectively for class tests and exams.

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Class 8 Science Worksheet

Chapter 12 – How Nature Works in Harmony

Curiosity | Practice Worksheet

Name: __________________________

Class: __________

Date: __________

Section A – Multiple Choice Questions

1. Which of the following is an abiotic component of an ecosystem?

□ (a) Grass

□ (b) Fish

□ (c) Sunlight

□ (d) Bacteria

2. A group of organisms of the same type living in an area is called a:

□ (a) Community

□ (b) Population

□ (c) Ecosystem

□ (d) Habitat

3. Which organism is a producer?

□ (a) Deer

□ (b) Tiger

□ (c) Green plant

□ (d) Mushroom

4. Which organisms help in decomposition?

□ (a) Fungi and bacteria

□ (b) Deer and hare

□ (c) Eagles and snakes

□ (d) Butterflies and bees

5. Which of the following shows a food chain?

□ (a) Grass → Grasshopper → Frog → Snake

□ (b) Frog → Grass → Snake → Grasshopper

□ (c) Snake → Grass → Frog → Eagle

□ (d) Eagle → Grass → Frog → Snake

6. Which interaction benefits both organisms?

□ (a) Parasitism

□ (b) Mutualism

□ (c) Competition

□ (d) Predation

7. Which of the following is an example of commensalism?

□ (a) Tick and dog

□ (b) Bee and flower

□ (c) Orchid and tree

□ (d) Tiger and deer

8. The position of an organism in a food chain is called its:

□ (a) Habitat

□ (b) Trophic level

□ (c) Population

□ (d) Community

Section B – Fill in the Blanks

1. A place where an organism lives is called its .

2. Living components of an ecosystem are called components.

3. Non-living components of an ecosystem are called components.

4. Green plants are called because they make their own food.

5. Organisms that break down dead matter are called .

6. A network of interconnected food chains is called a .

7. Transfer of pollen from one flower part to another is called .

8. An interaction in which both organisms benefit is called .

Section C – True or False

1. Sunlight is a biotic component. ________

2. Plants are usually producers in an ecosystem. ________

3. A community contains only one population. ________

4. Decomposers help recycle nutrients. ________

5. A food web contains several interconnected food chains. ________

6. In parasitism, both organisms benefit. ________

7. Mangrove forests can help protect coastal areas. ________

8. Humans do not depend on ecosystems. ________

Section D – Match the Following

Column A	Column B
1. Producer	A. Breaks down dead matter
2. Decomposer	B. Both organisms benefit
3. Mutualism	C. Makes its own food
4. Population	D. Network of food chains
5. Food web	E. Same type of organisms living in an area

Answers:

1. ______ 2. ______ 3. ______ 4. ______ 5. ______

Section E – Very Short Answer Questions

1. What is a habitat?

2. Give two examples of abiotic components.

3. What is a population?

4. What is an ecosystem?

5. What are decomposers?

6. What is a food chain?

7. What is a food web?

8. What is mutualism?

Section F – Short Answer Questions

1. Differentiate between biotic and abiotic components with two examples each.

2. How are population and community different?

3. Why are decomposers important in an ecosystem?

4. Why are plants important for animals in an ecosystem?

5. How can a change in one population affect other organisms?

6. What is the difference between a food chain and a food web?

Section G – Food Chain Practice

1. Complete the food chain:

Grass → __________ → Frog → __________ → Eagle

2. Arrange the following organisms in the correct feeding order:

Snake, Grass, Eagle, Frog, Grasshopper

3. Identify the producer in the following food chain:

Wheat → Mouse → Snake → Eagle

4. What would happen if snakes suddenly disappeared from the food chain?

5. Construct one food chain using the following organisms:

Grass, Deer, Tiger, Plants

Section H – Think and Answer

1. A pond has many fish. The fish population suddenly decreases. What changes might occur in the pond ecosystem?

2. Why can cutting down forests affect animals living far away from the forest?

3. Why can overuse of pesticides harm organisms other than pests?

4. How can planting flowering plants help butterflies and bees?

5. Why are mangrove forests important for coastal regions?

Section I – Case Study

A farmer noticed that the number of frogs around his fields had decreased. After some time, he noticed more insects damaging his crops. He started using more pesticides to control the insects.

Answer the following:

(a) Why did the insect population increase?

(b) How were frogs connected with the insect population?

(c) How might excessive pesticide use affect the ecosystem?

Section J – Application Based Questions

1. A school garden has many plants but very few butterflies. Suggest three possible reasons and three solutions.

2. A pond contains plants, fish, frogs, insects, microorganisms, water, sunlight and soil. Explain why this can be called an ecosystem.

3. If all decomposers disappeared from a forest, what would happen after a long time?

4. Why can the disappearance of one species affect several other species?

Section K – Higher Order Thinking Questions

1. Suppose all insects disappeared from a grassland. Predict two changes that could occur in the ecosystem.

2. Imagine a forest where there are producers but no consumers. Would the ecosystem remain balanced? Explain.

3. A farmer grows only one crop year after year and uses large amounts of chemical fertilisers. What problems could arise?

4. How can humans use ecosystems without destroying them?

Section L – Create Your Own Food Web

Use the following organisms to draw a food web:

Grass, Grasshopper, Mouse, Frog, Snake, Hare, Eagle

Section M – Ecosystem Around Me

Observe any place near your home or school and complete the table.

Component	Your Observation
Plants
Animals
Microorganisms
Water
Soil
Sunlight
Other observations

How are the living and non-living components connected in this place?

Section N – Challenge Yourself

1. If the number of grasshoppers in a grassland increases greatly, what may happen to grass and frogs?

2. If there are fewer flowering plants in an area, how might this affect bees and butterflies?

3. Why should wetlands and forests be protected even when humans do not directly use them?

4. Explain how one small change in an ecosystem can sometimes create many other changes.

Section O – Quick Revision

Term	Meaning
Habitat	Place where an organism lives.
Biotic	Living components.
Abiotic	Non-living components.
Population	Same type of organisms living in an area.
Community	Different populations living together.
Ecosystem	Biotic and abiotic components interacting.
Producer	Makes its own food.
Consumer	Gets food from other organisms.
Decomposer	Breaks down dead matter.
Food chain	Shows who eats whom.
Food web	Interconnected food chains.
Mutualism	Both organisms benefit.
Commensalism	One benefits and the other is unaffected.
Parasitism	One benefits and the other is harmed.

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Class 8 Science Chapter 12 – How Nature Works in Harmony | NCERT Curiosity Worksheet