Class 10th Science Chapter 13 – Our Environment | Components of an Ecosystem

🌍 Our Environment

Components of an Ecosystem | Class 10 Science | CBSE + Foundation + Competitive

🌍 Our Environment | Components of an Ecosystem

1. What is an Ecosystem? | पारितंत्र क्या है?

Ecosystem: An ecosystem is a functional unit of nature in which living organisms interact with one another and with the non-living components of their surroundings.

हिंदी: प्रकृति की वह कार्यात्मक इकाई जिसमें जीवित जीव एक-दूसरे तथा अपने अजैविक पर्यावरण के साथ अंतःक्रिया करते हैं, पारितंत्र (Ecosystem) कहलाता है।

Basic Structure:

Ecosystem = Biotic Components + Abiotic Components + Interactions

2. Major Components of an Ecosystem | पारितंत्र के प्रमुख घटक

3. Biotic Components | जैविक घटक

Biotic components are the living organisms present in an ecosystem.

हिंदी: पारितंत्र में उपस्थित सभी जीवित घटकों को जैविक घटक कहते हैं।

Biotic Group	Main Function	Examples
Producers	Prepare food and capture energy	Green plants, algae
Consumers	Obtain food from other organisms	Deer, tiger, humans
Decomposers	Break down dead organic matter	Bacteria, fungi

4. Producers | उत्पादक

Producers are organisms that prepare their own food, mainly through photosynthesis.

हिंदी: वे जीव जो अपना भोजन स्वयं बनाते हैं, मुख्यतः प्रकाश संश्लेषण द्वारा, उत्पादक कहलाते हैं।

Examples: Green plants, algae and some photosynthetic microorganisms.

Producers form the first trophic level of a food chain.

5. Role of Producers in Ecosystem | उत्पादकों की भूमिका

• Capture solar energy.
• Prepare organic food.
• Provide food to herbivores.
• Support higher trophic levels indirectly.
• Release oxygen during photosynthesis.

Sunlight → Green Plants → Chemical Energy in Food

6. Consumers | उपभोक्ता

Consumers are organisms that cannot generally prepare their own food and depend directly or indirectly on other organisms.

हिंदी: वे जीव जो सामान्यतः अपना भोजन स्वयं नहीं बना सकते और भोजन के लिए प्रत्यक्ष या अप्रत्यक्ष रूप से अन्य जीवों पर निर्भर रहते हैं, उपभोक्ता कहलाते हैं।

Consumer Type	Food	Example
Primary Consumer	Producers	Deer, rabbit, grasshopper
Secondary Consumer	Primary consumers	Frog, small fish
Tertiary Consumer	Lower consumers	Snake, large predatory fish
Omnivore	Plants + animals	Human, bear

7. Primary Consumers | प्राथमिक उपभोक्ता

Primary consumers feed directly on producers. They are generally herbivores.

हिंदी: प्राथमिक उपभोक्ता सीधे उत्पादकों पर भोजन के लिए निर्भर रहते हैं। ये सामान्यतः शाकाहारी होते हैं।

Grass → Deer
Producer → Primary Consumer

8. Secondary Consumers | द्वितीयक उपभोक्ता

Secondary consumers feed mainly on primary consumers.

Example: Grass → Grasshopper → Frog
Producer → Primary Consumer → Secondary Consumer

9. Tertiary and Higher Consumers | तृतीयक एवं उच्च उपभोक्ता

Tertiary consumers occupy higher trophic positions and feed on lower-level consumers.

Example:
Grass → Grasshopper → Frog → Snake → Eagle

10. Decomposers | अपघटक

Decomposers are organisms that break down dead plants, animals and organic wastes into simpler substances.

हिंदी: जीवाणु और कवक जैसे जीव जो मृत पौधों, जन्तुओं तथा जैविक अपशिष्टों को सरल पदार्थों में तोड़ते हैं, अपघटक कहलाते हैं।

Examples: Bacteria and fungi.

Important: Decomposers play a major role in recycling nutrients.

11. Importance of Decomposers | अपघटकों का महत्व

• Decompose dead organisms.
• Break complex organic substances into simpler substances.
• Return nutrients to soil and environment.
• Support nutrient cycling.
• Prevent excessive accumulation of dead organic matter.

12. Abiotic Components | अजैविक घटक

Abiotic components are the non-living physical and chemical factors of an ecosystem.

हिंदी: पारितंत्र के निर्जीव भौतिक एवं रासायनिक घटकों को अजैविक घटक कहते हैं।

Abiotic Factor	Importance
Sunlight	Major energy source for most ecosystems
Water	Essential for metabolic activities and life
Air	Provides gases such as oxygen and carbon dioxide
Soil	Provides minerals, water and support to plants
Temperature	Influences enzyme activity and survival
Minerals	Required for growth and metabolism

13. Sunlight | सूर्य का प्रकाश

Sunlight is the primary energy source for most ecosystems.

Plants use sunlight during photosynthesis to prepare food.

Sunlight → Photosynthesis → Chemical Energy

14. Water | जल

Water is essential for all known forms of life. It participates in metabolic reactions, transport, photosynthesis and temperature regulation.

हिंदी: जल जीवन की विभिन्न जैविक क्रियाओं, पदार्थों के परिवहन, प्रकाश संश्लेषण तथा तापमान नियंत्रण के लिए आवश्यक है।

15. Air and Atmospheric Gases | वायु एवं गैसें

Gas	Role in Ecosystem
Oxygen	Required for aerobic respiration.
Carbon dioxide	Used by green plants during photosynthesis.
Nitrogen	Important for proteins and nucleic acids after conversion into usable forms through nitrogen cycling.

16. Soil | मृदा

Soil provides physical support, water and minerals to plants and serves as a habitat for many organisms.

हिंदी: मृदा पौधों को सहारा, जल और खनिज प्रदान करती है तथा अनेक जीवों के लिए आवास भी है।

17. Temperature | तापमान

Temperature affects:

• Rate of chemical reactions.
• Enzyme activity.
• Growth and reproduction.
• Distribution and survival of organisms.

18. Interaction Between Biotic and Abiotic Components | जैविक एवं अजैविक घटकों की अंतःक्रिया

Biotic and abiotic components are interdependent.

For example, plants need sunlight, water, carbon dioxide, suitable temperature and minerals to grow. Animals depend on plants or other animals for food. Decomposers return nutrients to the environment.

Abiotic Factors → Producers → Consumers → Decomposers → Nutrients → Producers

19. Energy Flow in an Ecosystem | ऊर्जा प्रवाह

20. Trophic Levels | पोषण स्तर

Each step in a food chain is called a trophic level.

Trophic Level	Component	Example
1st	Producer	Grass
2nd	Primary Consumer	Deer
3rd	Secondary Consumer	Frog
4th	Higher Consumer	Snake/Eagle

21. Food Chain and Components | खाद्य श्रृंखला एवं घटक

Grass → Grasshopper → Frog → Snake → Eagle

Organism	Role	Trophic Level
Grass	Producer	1st
Grasshopper	Primary Consumer	2nd
Frog	Secondary Consumer	3rd
Snake	Higher Consumer	4th
Eagle	Top Consumer	Higher level

22. Ten Percent Law | दस प्रतिशत नियम

Approximately 10% of the energy available at one trophic level is transferred to the next trophic level.

Example:
1000 J → 100 J → 10 J → 1 J

This reduction in available energy limits the number of trophic levels in a food chain.

23. Food Web | खाद्य जाल

A food web is a network of interconnected food chains.

An organism may have more than one food source and may be eaten by more than one organism.

24. Natural and Artificial Ecosystems | प्राकृतिक एवं कृत्रिम पारितंत्र

Natural Ecosystem	Artificial Ecosystem
Develops naturally.	Created or maintained by humans.
Forest	Crop field
Pond	Aquarium
Lake	Garden

25. Ecosystem Components – Quick Revision Table

Component	Meaning	Examples
Biotic	Living components	Plants, animals, microorganisms
Abiotic	Non-living components	Water, air, soil, light
Producer	Prepares food	Green plants
Primary Consumer	Feeds on producers	Deer, rabbit
Secondary Consumer	Feeds on primary consumers	Frog
Decomposer	Breaks down dead matter	Bacteria, fungi

26. 30 MCQs | Multiple Choice Questions

1. An ecosystem consists of:

A. Only plants

B. Only animals

C. Only microorganisms

D. Biotic and abiotic components

Answer: D

2. Which is a biotic component?

A. Water

B. Soil

C. Grass

D. Temperature

Answer: C

3. Which is an abiotic component?

A. Deer

B. Water

C. Grass

D. Fungi

Answer: B

4. Green plants are:

A. Producers

B. Primary consumers

C. Secondary consumers

D. Decomposers

Answer: A

5. Bacteria and fungi generally act as:

A. Producers

B. Decomposers

C. Herbivores

D. Primary consumers

Answer: B

6. A deer is generally a:

A. Producer

B. Decomposer

C. Primary consumer

D. Tertiary consumer

Answer: C

7. The first trophic level consists of:

A. Producers

B. Herbivores

C. Carnivores

D. Decomposers

Answer: A

8. The main energy source for most ecosystems is:

A. Soil

B. Water

C. Sun

D. Minerals

Answer: C

9. Primary consumers feed mainly on:

A. Decomposers

B. Producers

C. Carnivores

D. Abiotic factors

Answer: B

10. Decomposers help in:

A. Nutrient recycling

B. Stopping decomposition

C. Producing sunlight

D. Increasing trophic levels

Answer: A

11. Which is NOT a biotic component?

A. Plant

B. Bacteria

C. Soil

D. Animal

Answer: C

12. Which gas is directly used by plants during photosynthesis?

A. Oxygen

B. Carbon dioxide

C. Nitrogen gas directly

D. Hydrogen

Answer: B

13. Which is a primary consumer?

A. Tiger

B. Deer

C. Eagle

D. Snake

Answer: B

14. Which is a decomposer?

A. Mushroom

B. Deer

C. Grass

D. Eagle

Answer: A

15. Which is an artificial ecosystem?

A. Forest

B. Lake

C. Aquarium

D. River

Answer: C

16. Which is a natural ecosystem?

A. Aquarium

B. Forest

C. Crop field

D. Garden

Answer: B

17. A food chain begins generally with:

A. Producers

B. Carnivores

C. Decomposers

D. Tertiary consumers

Answer: A

18. A food web consists of:

A. One organism

B. Only producers

C. Interconnected food chains

D. Only decomposers

Answer: C

19. Each step of a food chain is called:

A. Habitat

B. Trophic level

C. Population

D. Community

Answer: B

20. Approximately what percentage of energy passes to the next trophic level?

A. 90%

B. 50%

C. 25%

D. 10%

Answer: D

21. Which component provides minerals to plants?

A. Soil

B. Tiger

C. Frog

D. Eagle

Answer: A

22. Which factor directly provides energy for photosynthesis?

A. Soil

B. Sunlight

C. Nitrogen

D. Temperature alone

Answer: B

23. Which organisms generally occupy the second trophic level?

A. Producers

B. Primary consumers

C. Decomposers

D. Abiotic factors

Answer: B

24. Which process returns nutrients from dead organisms to the environment?

A. Decomposition

B. Photosynthesis

C. Respiration only

D. Transpiration

Answer: A

25. Which is a physical factor?

A. Bacteria

B. Grass

C. Temperature

D. Deer

Answer: C

26. Energy flow through trophic levels is generally:

A. Unidirectional

B. Completely circular

C. Absent

D. Random only

Answer: A

27. Which organism occupies the producer level?

A. Grass

B. Rabbit

C. Frog

D. Snake

Answer: A

28. Which statement is correct?

A. Consumers prepare all their food themselves

B. Decomposers help recycle nutrients

C. Abiotic factors are living

D. Producers depend only on consumers

Answer: B

29. Which is a correct sequence?

A. Consumer → Producer → Sun

B. Sun → Producer → Consumer

C. Decomposer → Sun → Producer

D. Consumer → Sun → Producer

Answer: B

30. The most fundamental source of energy for most ecosystems is:

A. Soil

B. Water

C. Sunlight

D. Minerals

Answer: C

27. 30 Subjective Questions with Answers

2 Marks Q1. Define ecosystem.

An ecosystem is a functional unit of nature in which living organisms interact with one another and with the non-living environment.

2 Marks Q2. Name the two major components of an ecosystem.

The two major components are:
1. Biotic components.
2. Abiotic components.

2 Marks Q3. What are biotic components?

Biotic components are the living components of an ecosystem, such as plants, animals and microorganisms.

2 Marks Q4. What are abiotic components?

Abiotic components are non-living physical and chemical factors such as air, water, soil, sunlight and temperature.

2 Marks Q5. Define producer.

A producer is an organism that prepares its own food, generally by photosynthesis.

2 Marks Q6. What is a consumer?

A consumer is an organism that obtains food directly or indirectly from other organisms.

2 Marks Q7. Define decomposer.

A decomposer is an organism that breaks down dead organic matter into simpler substances.

2 Marks Q8. Give two examples of decomposers.

Bacteria and fungi.

3 Marks Q9. Write three examples of abiotic components.

Air, water and sunlight are abiotic components. Soil and temperature are also examples.

3 Marks Q10. Write three functions of producers.

1. Capture solar energy.
2. Prepare food.
3. Provide energy-rich food to consumers.

3 Marks Q11. Why are decomposers important?

They decompose dead organisms, recycle nutrients and prevent accumulation of dead organic matter.

3 Marks Q12. Differentiate between biotic and abiotic components.

Biotic	Abiotic
Living components	Non-living components
Plants, animals, bacteria	Air, water, soil, temperature

3 Marks Q13. What are primary consumers?

Primary consumers feed directly on producers. They are generally herbivores such as deer, rabbit and grasshopper.

4 Marks Q14. Explain the major components of an ecosystem.

An ecosystem has two major components: biotic and abiotic. Biotic components include producers, consumers and decomposers. Abiotic components include air, water, soil, light, temperature and minerals. These components interact with each other.

4 Marks Q15. Explain the role of producers in an ecosystem.

Producers capture solar energy and convert it into chemical energy through photosynthesis. They form the first trophic level and provide food to herbivores and indirectly to higher consumers.

4 Marks Q16. Explain the role of consumers.

Consumers depend on other organisms for food. They transfer energy from producers to higher trophic levels and form important links in food chains and food webs.

4 Marks Q17. Explain the role of decomposers.

Decomposers break down dead organic matter into simpler substances. They return nutrients to the environment and help maintain nutrient cycles.

4 Marks Q18. Explain the importance of abiotic components.

Abiotic components provide the physical and chemical conditions necessary for life. Sunlight provides energy, water supports metabolic processes, soil provides minerals and temperature affects growth and survival.

5 Marks Q19. Explain how biotic and abiotic components are interdependent.

Plants require sunlight, water, carbon dioxide, minerals and suitable temperature. Animals depend on plants or other animals for food. Decomposers return nutrients to soil and water. Thus, living organisms continuously interact with non-living components.

5 Marks Q20. Explain the different types of consumers.

Primary consumers feed on producers and are generally herbivores. Secondary consumers feed mainly on primary consumers. Tertiary or higher consumers occupy higher trophic levels. Omnivores can consume both plant and animal food.

5 Marks Q21. Explain energy flow through an ecosystem.

Energy enters most ecosystems from sunlight. Producers capture it and store it as chemical energy. Consumers obtain this energy by feeding on producers or other consumers. Energy decreases at successive trophic levels because much is used in life processes and released as heat.

5 Marks Q22. Explain the ten percent law.

According to the ten percent law, approximately 10% of the energy available at one trophic level is transferred to the next. For example, 1000 J may result in about 100 J, then 10 J and then 1 J at successive levels.

5 Marks Q23. Explain food chain with an example.

A food chain represents the transfer of food and energy from one organism to another.

Example:
Grass → Grasshopper → Frog → Snake → Eagle

5 Marks Q24. Differentiate between food chain and food web.

Food chain: A single pathway of food and energy transfer.

Food web: A network of interconnected food chains showing multiple feeding relationships.

6 Marks Q25. Describe the components of an ecosystem in detail.

An ecosystem consists of:

1. Producers: Green plants and algae that prepare food.
2. Consumers: Herbivores, carnivores and omnivores that obtain food from other organisms.
3. Decomposers: Bacteria and fungi that break down dead organic matter.
4. Abiotic factors: Air, water, soil, sunlight, temperature and minerals.

All these components interact to maintain ecosystem functioning.

6 Marks Q26. Explain the importance of producers, consumers and decomposers.

Producers introduce energy into the biological system by capturing sunlight. Consumers transfer energy through feeding relationships. Decomposers break down dead matter and recycle nutrients. Together these groups maintain energy transfer and nutrient cycling.

6 Marks Q27. Explain how an ecosystem maintains itself.

An ecosystem functions through interactions among producers, consumers, decomposers and abiotic components. Producers capture energy, consumers transfer it through food chains, and decomposers recycle nutrients. Abiotic factors such as water, soil, sunlight and temperature provide essential conditions for these processes.

6 Marks Q28. Explain why decomposers are essential for ecosystem balance.

Without decomposers, dead organic matter would accumulate and nutrients would not be efficiently returned to the environment. This would reduce nutrient availability for producers and disturb ecosystem functioning. Therefore decomposers are essential for nutrient cycling.

6 Marks Q29. Explain the relationship among producers, consumers and decomposers.

Producers make food and store energy. Consumers obtain this food directly or indirectly. When organisms die, decomposers break down their remains and release nutrients back into the environment. Producers use these nutrients again. Thus, these groups are interconnected.

6 Marks Q30. Write a complete note on the components of an ecosystem.

An ecosystem contains biotic and abiotic components. Biotic components include producers, consumers and decomposers. Producers capture solar energy and make food. Consumers transfer energy through feeding relationships. Decomposers break down dead matter and recycle nutrients. Abiotic components include air, water, soil, sunlight, temperature and minerals. Continuous interaction among these components maintains ecosystem functioning.

28. Assertion–Reason Questions

Assertion (A): Producers occupy the first trophic level.
Reason (R): Producers prepare food using energy from sunlight.

Answer: Both A and R are true, and R correctly explains A.

Assertion (A): Decomposers are important for nutrient cycling.
Reason (R): They break down dead organic matter.

Answer: Both A and R are true, and R correctly explains A.

Assertion (A): Water is an abiotic component.
Reason (R): Water is a non-living physical factor of an ecosystem.

Answer: Both A and R are true, and R correctly explains A.

Assertion (A): Energy increases at higher trophic levels.
Reason (R): Only a small fraction of energy is transferred to the next trophic level.

Answer: Assertion is false, but Reason is true.

Assertion (A): Primary consumers generally feed directly on producers.
Reason (R): Primary consumers are generally herbivores.

Answer: Both A and R are true, and R correctly explains A.

29. HOTS | Higher Order Thinking

HOTS 1: What would happen if producers disappeared from an ecosystem?

The main entry of energy into the food chain would be disrupted. Herbivores would lose their food source, followed by higher consumers. The ecosystem would eventually collapse.

HOTS 2: Why are decomposers called nature's recyclers?

They break down dead organic matter and return nutrients to the environment, making these nutrients available again to producers.

HOTS 3: Why does energy decrease at successive trophic levels?

Organisms use energy for respiration, growth, movement and other activities. Much of the energy is released as heat, so only a small portion reaches the next trophic level.

HOTS 4: Why can changes in abiotic factors affect an entire ecosystem?

Abiotic factors determine the conditions in which organisms live. A major change in temperature, water availability or soil conditions can affect producers and consequently all dependent consumers.

HOTS 5: What may happen if decomposers are removed from an ecosystem?

Dead matter would accumulate and nutrient recycling would decline. Producers would eventually face reduced nutrient availability, affecting the entire food chain.

30. Important Diagrams and Rules

Remember these diagrams for examination:

🌞 Sun → 🌱 Producers → 🐇 Primary Consumers → 🐸 Secondary Consumers → 🐍 Higher Consumers

♻️ Dead Matter → Decomposers → Nutrients → Producers

Core Rule:
Approximately 10% energy passes from one trophic level to the next.

31. Golden Points | परीक्षा के लिए महत्वपूर्ण

✔ Ecosystem has biotic and abiotic components.

✔ Producers form the first trophic level.

✔ Green plants are the major producers.

✔ Primary consumers generally eat producers.

✔ Bacteria and fungi are important decomposers.

✔ Decomposers recycle nutrients.

✔ Sunlight is the major energy source for most ecosystems.

✔ Energy flow is unidirectional.

✔ Approximately 10% energy is transferred to the next trophic level.

✔ Food web consists of interconnected food chains.

32. One-Minute Revision

Ecosystem → Biotic + Abiotic + Interaction

Biotic → Producers + Consumers + Decomposers

Abiotic → Air + Water + Soil + Light + Temperature + Minerals

Producer → Makes food

Consumer → Gets food from other organisms

Decomposer → Breaks down dead matter

Food Chain → One feeding pathway

Food Web → Interconnected food chains

Energy → Sun → Producers → Consumers

Ten Percent Law → About 10% energy passes to next trophic level

33. Concept Map | अवधारणा मानचित्र

34. Final Summary

An ecosystem is a functional unit of nature consisting of interacting biotic and abiotic components.

The biotic components include producers, consumers and decomposers. Producers such as green plants prepare food and capture solar energy. Consumers obtain food from producers or other consumers. Decomposers such as bacteria and fungi break down dead organic matter and recycle nutrients.

The abiotic components include sunlight, air, water, soil, temperature and minerals. These factors provide the physical and chemical conditions necessary for life.

All these components are interconnected. Energy generally flows from the Sun to producers and then through successive trophic levels, while nutrients are continuously recycled through decomposition and other natural processes.

Core Concept:
🌞 Sun → 🌱 Producers → 🐇 Consumers → 🦅 Higher Consumers

♻️ Decomposers → Nutrient Recycling → Producers

🌍 Class 10 Science | Our Environment

Components of Ecosystem • Biotic • Abiotic • Producers • Consumers • Decomposers • Energy Flow • Trophic Levels • Food Chain • Food Web

CBSE + Foundation + Competitive Preparation