📚 HISTORY GK |August Offer, Individual Satyagraha, Cripps Mission & Quit India Movement

 

📚 HISTORY GK 

August Offer, Individual Satyagraha, Cripps Mission & Quit India Movement

प्रतियोगी परीक्षाओं के लिए 100 महत्वपूर्ण MCQs + विस्तृत अध्ययन सामग्री

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 परिचय | Introduction

भारतीय स्वतंत्रता आंदोलन के इतिहास में 1940 से 1942 का काल अत्यंत महत्वपूर्ण था। यह वह समय था जब द्वितीय विश्व युद्ध के बीच ब्रिटिश सरकार भारत से राजनीतिक और सैन्य सहयोग चाहती थी, जबकि भारतीय राष्ट्रीय आंदोलन तत्काल राजनीतिक अधिकार और स्वतंत्रता की मांग को और अधिक मजबूत कर रहा था।

इस अवधि में तीन महत्वपूर्ण घटनाएँ हुईं—August Offer (1940), Individual Satyagraha (1940–41) और Cripps Mission (1942)। इन घटनाओं के बाद परिस्थितियाँ तेजी से बदलीं और अंततः Quit India Movement (भारत छोड़ो आंदोलन), 1942 शुरू हुआ।

Class 10th Science Chapter 15 – Our Environment and Sustainable Management | Producers, Consumers and Decomposers

Our Environment and Sustainable Management

Producers, Consumers and Decomposers

उत्पादक, उपभोक्ता एवं अपघटक

Class 10 CBSE Science | Foundation | Competitive Preparation

🌱 Producers, Consumers and Decomposers

1. Introduction | परिचय

An ecosystem contains many types of organisms. Based on how organisms obtain food and energy, they can broadly be grouped into producers, consumers and decomposers.

हिंदी: परितंत्र में विभिन्न प्रकार के जीव पाए जाते हैं। भोजन और ऊर्जा प्राप्त करने के तरीके के आधार पर इन्हें मुख्यतः उत्पादक, उपभोक्ता और अपघटक में बाँटा जाता है।

Sun → Producers → Consumers → Decomposers → Nutrients → Producers

CBSE Key Point: Producers, consumers and decomposers are interconnected. Together they help maintain energy transfer and nutrient cycling in an ecosystem.

2. Producers | उत्पादक

Producers are organisms capable of producing organic food from simpler inorganic substances. Most producers use sunlight as their energy source and perform photosynthesis.

हिंदी: उत्पादक वे जीव हैं जो सरल अकार्बनिक पदार्थों से अपना कार्बनिक भोजन बनाते हैं। अधिकांश उत्पादक सूर्य के प्रकाश की ऊर्जा का उपयोग करके प्रकाश-संश्लेषण करते हैं।

🌳

☀️ Light
Energy

→

🌱 Green Plant
Producer

→

🍎 Organic Food
Chemical Energy

3. Photosynthesis in Producers

Green plants contain chlorophyll, which absorbs light energy. This energy is used to synthesize glucose from carbon dioxide and water.

6CO₂ + 6H₂O + Light Energy → C₆H₁₂O₆ + 6O₂

The glucose produced may be used for respiration, growth and other life processes, or converted into storage materials such as starch.

Important: Producers are called autotrophs because they manufacture their own organic food.

4. Examples of Producers

Producer	Environment
🌾 Wheat, rice and other crops	Agricultural ecosystem
🌳 Trees	Forest ecosystem
🌿 Grass	Grassland ecosystem
🌱 Aquatic plants	Pond/lake ecosystem
🟢 Algae	Aquatic ecosystem

5. Why are Producers Important?

Producers are extremely important because they form the base of most food chains and are the main entry point of energy into ecosystems.

Major functions of producers:

• Manufacture organic food.
• Capture solar energy.
• Provide food to herbivores.
• Support higher trophic levels indirectly.
• Release oxygen during photosynthesis.
• Store chemical energy in organic matter.

6. Consumers | उपभोक्ता

Consumers are organisms that obtain food by feeding on producers or other organisms. They generally cannot manufacture organic food in the same way as producers.

Consumers are called heterotrophs because they depend directly or indirectly on other organisms for organic food.

🌱
Producer

→

🐇
Consumer

→

🐍
Higher Consumer

→

🦅
Top Consumer

7. Types of Consumers

Type	Food	Examples
Primary Consumers	Feed directly on producers.	Deer, rabbit, cow, grasshopper
Secondary Consumers	Feed on primary consumers.	Frog, lizard, small carnivorous fish
Tertiary Consumers	Feed on secondary consumers.	Snake, large predatory fish
Top Consumers	Occupy a high position in a food chain.	Eagle, tiger, lion

8. Primary Consumers | प्राथमिक उपभोक्ता

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

🌱
Grass

→

🐇
Rabbit

→

🦊
Fox

Grass = Producer

Rabbit = Primary Consumer

Examples: cow, deer, rabbit, goat, grasshopper and many zooplankton.

9. Secondary Consumers | द्वितीयक उपभोक्ता

Secondary consumers generally feed on primary consumers. They may be carnivores or omnivores depending on the food chain.

🌿
Plants

→

🦗
Grasshopper

→

🐸
Frog

Frog acts as a secondary consumer in this example.

10. Tertiary Consumers | तृतीयक उपभोक्ता

Tertiary consumers occupy a higher trophic position and feed on secondary consumers in a given food chain.

🌾
Grass

→

🦗
Insect

→

🐸
Frog

→

🐍
Snake

Snake is a tertiary consumer in this particular food chain.

11. Herbivores, Carnivores and Omnivores

Group	Definition	Examples
🌿 Herbivores	Animals that feed mainly on plants.	Cow, deer, rabbit
🥩 Carnivores	Animals that feed mainly on other animals.	Lion, tiger, snake
🍃🥩 Omnivores	Animals that consume both plant and animal food.	Humans, bears, crows

An organism can occupy different trophic positions depending on what it eats.

12. Omnivores and Multiple Trophic Levels

An omnivore may feed on both plants and animals. Therefore, its trophic position can vary according to its diet.

🌾
Plants

→

👨
Human

🌾

→

🐄

→

👨

The same organism may have different trophic positions in different food pathways.

13. Decomposers | अपघटक

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

The major decomposers include bacteria and fungi.

🌳
Plant

→

🐄
Animal

→

🍄 🦠
Dead Matter

→

♻️
Nutrients

→

🌱
Plants

14. How Decomposition Takes Place

Decomposers release enzymes onto dead organic material. Complex organic substances are broken down into simpler substances that can be returned to the environment.

Dead Organic Matter → Decomposition → Simpler Substances → Nutrient Recycling

Decomposition helps return elements and minerals to soil and other parts of the environment. These nutrients can subsequently become available to producers.

15. Importance of Decomposers

Decomposers perform several essential ecological functions:

• Break down dead organisms.
• Decompose organic wastes.
• Prevent excessive accumulation of dead matter.
• Return nutrients to the environment.
• Support nutrient cycling.
• Help maintain ecosystem functioning.

16. Detritivores vs Decomposers

Detritivores	Decomposers
Feed on dead organic matter or detritus.	Break down organic matter chemically using enzymes.
Often fragment dead material.	Convert complex organic matter into simpler substances.
Example: Earthworm.	Examples: Bacteria and fungi.

17. Producers vs Consumers

Producers	Consumers
Make organic food.	Obtain food from other organisms.
Usually autotrophic.	Generally heterotrophic.
Usually occupy the first trophic level.	Occupy higher trophic levels depending on diet.
Examples: plants and algae.	Examples: deer, frog, snake and eagle.

18. Consumers vs Decomposers

Consumers	Decomposers
Obtain food by feeding on organisms or organic matter.	Break down dead organic matter chemically.
Usually ingest food.	Often digest externally using enzymes.
Examples: deer, frog, tiger.	Examples: bacteria and fungi.

19. Complete Food-Energy Relationship

☀️ 🌱
Producers
Capture Energy

→

🐇
Primary
Consumers

→

🐍
Secondary
Consumers

→

🦅
Higher
Consumers

🍄 🦠
Decomposers

→

♻️
Nutrients

→

🌱
Producers

20. Producers, Consumers and Decomposers in a Forest

Category	Examples	Role
Producers	Trees, shrubs, grasses	Produce organic food and store energy.
Consumers	Deer, insects, birds, carnivores	Transfer energy through feeding relationships.
Decomposers	Bacteria, fungi	Break down dead organic matter and recycle nutrients.

21. Producers, Consumers and Decomposers in a Pond

Category	Examples
Producers	Algae, phytoplankton, aquatic plants
Consumers	Zooplankton, insects, fish, frogs
Decomposers	Bacteria and fungi

22. Energy Flow vs Nutrient Cycling

Energy Flow	Nutrient Cycling
Energy enters most ecosystems mainly through sunlight.	Nutrients are transferred between organisms and the environment.
Flow is unidirectional.	Matter can be recycled.
Energy is eventually dissipated as heat.	Nutrients can become available to producers again.

Remember: Energy flows; nutrients cycle.

23. Trophic Levels and These Three Groups

TL 1
🌱 Producers TL 2
🐇 Primary Consumers TL 3
🐸 Secondary Consumers TL 4
🦅 Higher Consumers

Decomposers act on dead organic matter from organisms at different trophic levels.

24. 10% Law and Producers–Consumers Relationship

According to the commonly taught 10% law, approximately 10% of the energy available at one trophic level is transferred to the next trophic level.

10,000 J → 1,000 J → 100 J → 10 J

This explains why energy available generally decreases at successive trophic levels and why food chains usually have limited length.

25. What if Producers Decrease?

If producers decrease significantly, less food and energy become available to primary consumers. This can affect secondary and higher consumers as well.

Therefore, destruction of vegetation can produce effects throughout a food web rather than affecting only plants.

26. What if Decomposers Disappear?

If decomposers disappeared, dead organic matter would accumulate and nutrient recycling would be severely disrupted.

Over time, reduced nutrient availability could affect producers and therefore the entire ecosystem.

27. What if a Top Consumer is Removed?

Removing a predator can change prey populations. For example, if a major predator declines, some prey populations may increase, potentially increasing pressure on their food resources.

This is an example of how interconnected food webs can respond to changes in one population.

28. Producers, Consumers and Sustainable Management

Sustainable ecosystem management requires protection of producers, balanced populations of consumers and maintenance of decomposer activity.

Component	Sustainable Management
Producers	Protect forests, grasslands, crops and aquatic vegetation.
Consumers	Protect habitats and avoid excessive exploitation of wildlife.
Decomposers	Maintain soil health and natural decomposition processes.

29. 30 MCQs with Answers

1. Which organisms are called producers?

A. Organisms that manufacture organic food

B. Organisms that only eat animals

C. Organisms that decompose dead matter

D. Organisms that cannot obtain energy

Answer: A

2. Which is a producer?

A. Tiger

B. Grass

C. Frog

D. Snake

Answer: B

3. Producers are generally:

A. Carnivores

B. Decomposers

C. Autotrophs

D. Detritivores

Answer: C

4. Which process is mainly responsible for food production in green plants?

A. Digestion

B. Photosynthesis

C. Decomposition

D. Excretion

Answer: B

5. Which organisms generally feed directly on producers?

A. Primary consumers

B. Tertiary consumers

C. Decomposers

D. Top predators only

Answer: A

6. A deer is generally a:

A. Producer

B. Decomposer

C. Herbivorous primary consumer

D. Tertiary consumer

Answer: C

7. Which is a secondary consumer in a suitable food chain?

A. Grass

B. Rabbit

C. Frog feeding on insects

D. Algae

Answer: C

8. Which is a major group of decomposers?

A. Birds

B. Mammals

C. Reptiles

D. Bacteria and fungi

Answer: D

9. Decomposers mainly act on:

A. Sunlight

B. Dead organic matter

C. Rocks only

D. Clouds

Answer: B

10. Decomposers help in:

A. Nutrient recycling

B. Producing sunlight

C. Stopping decomposition

D. Eliminating all consumers

Answer: A

11. Which animal is generally an omnivore?

A. Cow

B. Human

C. Grass

D. Algae

Answer: B

12. An animal feeding mainly on plants is called:

A. Carnivore

B. Omnivore

C. Herbivore

D. Decomposer

Answer: C

13. An animal feeding mainly on other animals is a:

A. Carnivore

B. Producer

C. Herbivore

D. Decomposer

Answer: A

14. Which group forms the base of most food chains?

A. Top consumers

B. Producers

C. Decomposers

D. Carnivores

Answer: B

15. Which substance is an important raw material for photosynthesis?

A. Carbon dioxide

B. Nitrogen gas only

C. Methane

D. Helium

Answer: A

16. Which pigment helps green plants capture light energy?

A. Haemoglobin

B. Chlorophyll

C. Melanin

D. Keratin

Answer: B

17. Which is an aquatic producer?

A. Algae

B. Tiger

C. Frog

D. Snake

Answer: A

18. Which statement about decomposers is correct?

A. They prevent nutrient cycling

B. They break down dead organic matter

C. They are always producers

D. They use sunlight to make all food

Answer: B

19. A rabbit in Grass → Rabbit → Snake is:

A. Producer

B. Primary consumer

C. Secondary consumer

D. Decomposer

Answer: B

20. In Grass → Grasshopper → Frog → Snake, frog is:

A. Producer

B. Primary consumer

C. Secondary consumer

D. Decomposer

Answer: C

21. In the same food chain, snake is:

A. Producer

B. Primary consumer

C. Secondary consumer

D. Tertiary consumer

Answer: D

22. Energy enters most ecosystems mainly through:

A. Decomposers

B. Sunlight captured by producers

C. Soil minerals

D. Consumers

Answer: B

23. Which statement is correct?

A. Energy flows and nutrients are recycled

B. Energy is completely recycled

C. Nutrients never return to the environment

D. Decomposers stop nutrient cycling

Answer: A

24. Which organism is a detritivore?

A. Earthworm

B. Grass

C. Eagle

D. Algae

Answer: A

25. Which group helps prevent accumulation of dead organic matter?

A. Producers only

B. Decomposers

C. Herbivores only

D. Top consumers only

Answer: B

26. Which is NOT a consumer?

A. Deer

B. Frog

C. Grass

D. Tiger

Answer: C

27. If producers decrease sharply, the first major effect is likely to be:

A. Increased food availability for herbivores

B. Reduced food availability for primary consumers

C. Immediate increase in all predators

D. Elimination of abiotic factors

Answer: B

28. What would happen if decomposers disappeared?

A. Nutrient recycling would be disrupted

B. Photosynthesis would increase automatically

C. Dead matter would disappear instantly

D. All consumers would become producers

Answer: A

29. Which group is mainly responsible for converting dead organic matter into simpler substances?

A. Producers

B. Herbivores

C. Decomposers

D. Top consumers

Answer: C

30. Which sequence is correct?

A. Consumers → Producers → Sun → Decomposers

B. Sun → Producers → Consumers → Decomposers

C. Decomposers → Sun → Consumers → Producers

D. Producers → Sun → Decomposers → Consumers

Answer: B

30. Subjective Questions with Answers

2 Marks 1. What are producers?

Producers are organisms that manufacture organic food from simpler substances, usually using sunlight. Green plants and algae are common producers.

2 Marks 2. Give two examples of producers.

Green plants and algae.

2 Marks 3. What are consumers?

Consumers are organisms that obtain food by feeding on producers or other organisms.

2 Marks 4. What are decomposers?

Decomposers are organisms such as bacteria and fungi that break down dead organic matter into simpler substances.

2 Marks 5. Name two major groups of decomposers.

Bacteria and fungi.

2 Marks 6. Define herbivore.

A herbivore is an animal that feeds mainly on plants or plant material.

3 Marks 7. Explain why producers are called autotrophs.

Producers manufacture their own organic food from simpler inorganic substances, mainly through photosynthesis. Therefore, they are called autotrophs.

3 Marks 8. Why are consumers called heterotrophs?

Consumers cannot manufacture organic food in the same way as producers and depend directly or indirectly on other organisms for food. Hence they are heterotrophs.

3 Marks 9. State three functions of decomposers.

They break down dead matter, prevent accumulation of organic wastes and return nutrients to the environment.

3 Marks 10. What is a primary consumer? Give two examples.

A primary consumer feeds directly on producers. Examples are deer and rabbit.

4 Marks 11. Differentiate between producers and consumers.

Producers manufacture organic food and generally occupy the first trophic level. Consumers obtain food by feeding on other organisms and occupy higher trophic levels depending on their diet.

4 Marks 12. Differentiate between consumers and decomposers.

Consumers obtain food by feeding on organisms or organic matter, whereas decomposers chemically break down dead organic matter and release simpler substances and nutrients.

4 Marks 13. Explain primary, secondary and tertiary consumers.

Primary consumers feed on producers. Secondary consumers feed on primary consumers. Tertiary consumers feed on secondary consumers in a given food chain.

4 Marks 14. Explain the importance of decomposers.

Decomposers break down dead organisms and organic waste, prevent accumulation of dead matter and help return nutrients to the environment.

4 Marks 15. Explain the role of producers in energy flow.

Producers capture solar energy and store it as chemical energy in organic food. This energy becomes available to consumers when they feed on producers.

5 Marks 16. Explain photosynthesis and its importance to producers.

During photosynthesis, green plants use light energy, carbon dioxide and water to synthesize glucose and release oxygen. The stored chemical energy supports the producer and other organisms that depend on it.

5 Marks 17. Explain different types of consumers with examples.

Primary consumers feed on producers, e.g. deer. Secondary consumers feed on primary consumers, e.g. frog. Tertiary consumers feed on secondary consumers, e.g. snake in a suitable food chain. Higher/top consumers occupy high trophic positions.

5 Marks 18. Explain the role of decomposers in nutrient cycling.

Decomposers break down dead plants, animals and organic wastes. This releases simpler substances and nutrients back into the environment, making them available for producers and supporting nutrient cycling.

5 Marks 19. Explain the relationship between producers, consumers and decomposers.

Producers manufacture organic food, consumers obtain energy by feeding on producers or other consumers, and decomposers break down dead matter and recycle nutrients. Thus all three groups are interconnected.

5 Marks 20. Explain the difference between energy flow and nutrient cycling.

Energy flows in one direction through trophic levels and is eventually dissipated as heat. Nutrients are transferred between organisms and the environment and can be recycled.

6 Marks 21. Describe the role of producers, consumers and decomposers in a forest ecosystem.

Trees, shrubs and grasses act as producers. Herbivores, carnivores and omnivores act as consumers. Bacteria and fungi act as decomposers. Producers provide organic food, consumers transfer energy through feeding and decomposers recycle nutrients.

6 Marks 22. Explain how a food chain connects producers and consumers.

A food chain begins with a producer. A primary consumer feeds on the producer, followed by secondary and higher consumers. Thus food and energy are transferred through successive trophic levels.

6 Marks 23. What would happen to an ecosystem if decomposers disappeared?

Dead organic matter would accumulate and decomposition would be severely reduced. Nutrient recycling would be disrupted, eventually affecting soil nutrient availability, producers and higher trophic levels.

6 Marks 24. What would happen if producers were greatly reduced?

Primary consumers would have less food. Their populations could decline, followed by effects on secondary and higher consumers. Overall energy availability and food-web stability could be reduced.

6 Marks 25. Explain why decomposers are considered essential for sustainable ecosystems.

They recycle nutrients from dead organic matter and wastes. Without their activity, nutrients would not be efficiently returned to the environment, weakening long-term ecosystem productivity.

6 Marks 26. Explain herbivores, carnivores and omnivores with examples.

Herbivores feed mainly on plants, e.g. cow. Carnivores feed mainly on animals, e.g. tiger. Omnivores feed on both plant and animal matter, e.g. humans.

6 Marks 27. Explain the 10% law in relation to producers and consumers.

Approximately 10% of energy available at one trophic level is transferred to the next. Thus if producers have 10,000 J, primary consumers may receive about 1,000 J, secondary consumers about 100 J and tertiary consumers about 10 J.

6 Marks 28. Explain why producers form the base of most ecosystems.

Producers convert external energy, mainly sunlight, into chemical energy stored in organic food. Consumers depend directly or indirectly on this food, making producers the foundation of most food chains.

6 Marks 29. Explain how human activities can affect producers, consumers and decomposers.

Deforestation can reduce producers, habitat destruction can reduce consumers, and pollution or harmful chemicals can affect decomposers and soil processes. These changes can disturb energy flow, food webs and nutrient cycling.

6 Marks 30. Explain the complete sequence from sunlight to nutrient recycling.

Sunlight provides energy to producers. Producers store it in organic food. Consumers obtain this food directly or indirectly. Dead organisms and wastes are decomposed by bacteria and fungi, returning nutrients to the environment. Producers use these nutrients again.

31. Assertion–Reason Questions

1. Assertion: Producers occupy the first trophic level.
Reason: Producers capture energy and convert it into chemical energy stored in organic matter.

Answer: Both statements are true and the Reason correctly explains the Assertion.

2. Assertion: Decomposers are essential for nutrient cycling.
Reason: They break down dead organic matter.

Answer: Both statements are true and the Reason correctly explains the Assertion.

3. Assertion: Primary consumers feed directly on producers.
Reason: Producers form the first trophic level.

Answer: Both statements are true and the Reason correctly explains the Assertion.

4. Assertion: Energy is recycled completely in an ecosystem.
Reason: Energy is dissipated as heat during energy transfer.

Answer: Assertion is false, but Reason is true.

5. Assertion: If producers decline greatly, consumers can also be affected.
Reason: Consumers depend directly or indirectly on producers for organic food.

Answer: Both statements are true and the Reason correctly explains the Assertion.

32. HOTS Questions

HOTS 1: Why can destruction of forests affect animals that do not eat plants directly?

Animals at higher trophic levels depend indirectly on producers through food chains. A decline in producers can therefore reduce energy and food available throughout the food web.

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

They break down dead organic matter and help return nutrients to the environment, where the nutrients can be reused by producers.

HOTS 3: Can an omnivore occupy different trophic levels? Explain.

Yes. Its trophic position depends on what it eats. When it eats plants it may act as a primary consumer; when it eats herbivores it can occupy a higher trophic position.

HOTS 4: Why does removal of a predator sometimes cause an increase in its prey population?

Predators control prey populations through feeding. If predation decreases, prey may face less mortality and their population can increase, subject to other limiting factors.

HOTS 5: Why is nutrient recycling important for producers?

Plants require mineral nutrients for growth and metabolism. Recycling makes nutrients from dead organisms and wastes available again in the ecosystem.

33. Quick Revision Table

Component	Key Function	Examples
🌱 Producers	Manufacture organic food and capture energy.	Plants, algae
🐇 Consumers	Obtain food by feeding on organisms.	Deer, frog, snake, tiger
🍄 Decomposers	Break down dead organic matter and recycle nutrients.	Bacteria, fungi

34. One-Minute Revision

🌱 Producers = Autotrophs
Make organic food, mainly through photosynthesis.

🐇 Primary Consumers
Feed directly on producers.

🐸 Secondary Consumers
Feed on primary consumers.

🐍 Tertiary Consumers
Feed on secondary consumers in a given food chain.

🦅 Top Consumers
Occupy high trophic positions.

🍄 Decomposers
Bacteria and fungi break down dead organic matter.

⚡ Energy
Flows through trophic levels and is eventually dissipated as heat.

♻️ Nutrients
Are recycled through ecosystem processes.

35. Golden Points for CBSE Exam

1. Producers are generally autotrophs.

2. Green plants and algae are common producers.

3. Producers occupy the first trophic level.

4. Consumers are generally heterotrophs.

5. Primary consumers feed directly on producers.

6. Secondary consumers generally feed on primary consumers.

7. Tertiary consumers occupy a higher trophic position.

8. Herbivores feed mainly on plants.

9. Carnivores feed mainly on animals.

10. Omnivores consume both plant and animal matter.

11. Bacteria and fungi are major decomposers.

12. Decomposers help in nutrient recycling.

13. Energy flow is unidirectional.

14. Nutrients can be recycled.

15. Energy transfer generally decreases at successive trophic levels.

36. MCQ Answer Key

Q	Ans	Q	Ans	Q	Ans
1	A	11	B	21	D
2	B	12	C	22	B
3	C	13	A	23	A
4	B	14	B	24	A
5	A	15	A	25	B
6	C	16	B	26	C
7	C	17	A	27	B
8	D	18	B	28	A
9	B	19	B	29	C
10	A	20	C	30	B

Our Environment and Sustainable Management
Producers • Consumers • Decomposers
Class 10 CBSE Science | Foundation | Competitive Preparation

Class 10th Science Chapter 15 – Our Environment and Sustainable Management | Ecosystem and Its Components

Our Environment and Sustainable Management

Ecosystem and Its Components

Class 10 CBSE Science | Foundation | Competitive Preparation

🌍 Ecosystem and Its Components | परितंत्र एवं इसके घटक

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

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

हिंदी: परितंत्र प्रकृति की एक कार्यात्मक इकाई है जिसमें जीव एक-दूसरे के साथ तथा अपने भौतिक एवं अजैविक पर्यावरण के साथ परस्पर क्रिया करते हैं।

Ecosystem = Biotic Components + Abiotic Components + Their Interactions

CBSE Exam Point: केवल जीवों का समूह ecosystem नहीं कहलाता। जीवों तथा उनके भौतिक पर्यावरण के बीच होने वाली पारस्परिक क्रियाएँ भी ecosystem का आवश्यक भाग हैं।

2. Basic Structure of an Ecosystem

🌳 Structure of Ecosystem

☀️ 🌧️ 🌡️
Abiotic Components
Light • Air • Water • Soil

↔

🌱 🌿
Producers
Plants & Algae

→

🐇 🐍 🦅
Consumers
Animals

→

🍄 🦠
Decomposers
Bacteria & Fungi

All these components interact continuously.

3. Main Components of an Ecosystem

An ecosystem has two major categories:

• Abiotic components – non-living physical and chemical factors.
• Biotic components – living organisms.

Major Component	Sub-components	Examples
Abiotic	Physical factors	Light, temperature, rainfall, humidity
Abiotic	Chemical factors	Water, oxygen, carbon dioxide, minerals, salts
Biotic	Producers	Green plants, algae
Biotic	Consumers	Herbivores, carnivores, omnivores
Biotic	Decomposers	Bacteria, fungi

4. Abiotic Components | अजैविक घटक

Abiotic components are the non-living factors of an ecosystem. They influence the survival, growth, reproduction and distribution of organisms.

Important Abiotic Factors

Factor	Role in Ecosystem
☀️ Sunlight	Provides energy for photosynthesis and influences daily/seasonal biological activities.
🌡️ Temperature	Affects metabolic activities, growth and distribution of organisms.
💧 Water	Essential for life processes and influences the types of organisms found in an ecosystem.
🌬️ Air	Provides gases such as oxygen and carbon dioxide required by organisms.
🌱 Soil	Provides support, water and minerals to plants and acts as habitat for many organisms.
🪨 Minerals	Required by plants and animals for various biological functions.
🌧️ Rainfall	Influences water availability, vegetation and ecosystem productivity.

5. Biotic Components | जैविक घटक

Biotic components are the living organisms present in an ecosystem. They are commonly grouped into producers, consumers and decomposers.

🌱
Producers
Autotrophs

🐄 🐅
Consumers
Heterotrophs

🍄 🦠
Decomposers
Bacteria & Fungi

6. Producers | उत्पादक

Producers are organisms that manufacture their own food, mainly through photosynthesis. Green plants and algae are important producers in many ecosystems.

Carbon dioxide + Water + Light Energy → Glucose + Oxygen

Plants convert light energy into chemical energy stored in organic food molecules. Therefore, producers form the primary entry point of energy into most ecosystems.

Examples: Grass, trees, crops, algae and many aquatic plants.

7. Consumers | उपभोक्ता

Consumers cannot manufacture their own food from inorganic substances in the same way as producers. They obtain organic food by feeding on plants or other organisms.

Consumer Type	Meaning	Example
Primary Consumer	Feeds directly on producers; generally herbivorous.	Deer, rabbit, grasshopper
Secondary Consumer	Feeds on primary consumers.	Frog, small carnivorous fish
Tertiary Consumer	Feeds on secondary consumers in a food chain.	Snake, large predatory fish
Top Consumer	May occupy a high trophic position with few or no natural predators in that food chain.	Eagle, tiger

8. Herbivores, Carnivores and Omnivores

Type	Food Habit	Examples
Herbivore	Feeds mainly on plants.	Cow, deer, rabbit
Carnivore	Feeds mainly on other animals.	Lion, tiger, snake
Omnivore	Feeds on both plant and animal matter.	Human, bear, crow

An omnivore may occupy more than one trophic level depending on what it eats.

9. Decomposers | अपघटक

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

Their activities help return nutrients to the environment, where producers can use them again.

♻️ Nutrient Recycling

🌱
Plants

→

🐇
Animals

→

🍄 🦠
Decomposers

→

🌱
Nutrients in Soil

→

🌿
Plants

Important: Decomposers are essential for nutrient cycling. Without decomposition, dead organic matter would accumulate and nutrients would not be efficiently returned to the ecosystem.

10. Detritivores and Decomposers – Difference

Detritivores	Decomposers
Feed on dead organic matter or detritus.	Break down complex organic matter chemically using enzymes.
Examples include earthworms and some insects.	Examples include bacteria and fungi.
Help fragment organic material.	Help chemically decompose organic matter and release nutrients.

11. Interaction Among Ecosystem Components

The components of an ecosystem are interconnected. Producers provide food and oxygen, consumers transfer energy through feeding relationships, and decomposers recycle nutrients.

Sun → Producers → Consumers → Decomposers → Nutrients → Producers

Energy flow and nutrient cycling are related but not identical. Energy flows through an ecosystem and is eventually dissipated as heat, whereas nutrients are recycled.

12. Energy Flow in an Ecosystem

In most ecosystems, solar energy is captured by producers and transferred through different trophic levels.

☀️ Energy Flow

☀️
Sun

→

🌱
Producers

→

🐇
Primary Consumers

→

🐍
Secondary Consumers

→

🦅
Higher Consumers

Energy flow is unidirectional.

13. Trophic Levels

A trophic level represents the feeding position of an organism in a food chain.

🌱 TL 1
Producers

🐇 TL 2
Primary Consumers

🐍 TL 3
Secondary Consumers

🦅 TL 4
Tertiary Consumers

Producers occupy the first trophic level. Primary consumers occupy the second, secondary consumers the third and so on.

14. Food Chain Example

🌱 Simple Food Chain

🌿
Grass

→

🐇
Rabbit

→

🐍
Snake

→

🦅
Eagle

Grass → Rabbit → Snake → Eagle

Arrow shows the direction of food/energy transfer.

15. Food Web

A food web is a network of interconnected food chains. It represents multiple feeding relationships within an ecosystem.

Food webs are generally more complex than individual food chains because organisms may have more than one food source and may be eaten by several organisms.

A food web can provide alternative feeding pathways and can contribute to ecosystem stability.

16. Habitat and Niche

Habitat is the physical place or environment where an organism normally lives.

Niche refers broadly to the role of an organism in an ecosystem, including how it uses resources and interacts with other organisms and its environment.

Habitat	Niche
Where an organism lives.	How an organism lives and its ecological role.
Example: Pond.	Example: A frog feeding on insects and serving as prey for larger organisms.

17. Pond Ecosystem

🌊🐟🌿

Example: Pond Ecosystem

Abiotic: Water, sunlight, dissolved oxygen, minerals, temperature and mud.

Producers: Algae and aquatic plants.

Consumers: Zooplankton, insects, fish, frogs and other animals.

Decomposers: Bacteria and fungi.

18. Forest Ecosystem

A forest ecosystem contains trees, shrubs, herbs, animals, microorganisms, soil, air, water, sunlight and temperature conditions.

Component	Examples
Producers	Trees, shrubs, grasses
Consumers	Deer, insects, birds, carnivores
Decomposers	Bacteria, fungi
Abiotic	Soil, water, light, temperature, air

19. Natural and Artificial Ecosystems

Natural Ecosystem	Artificial Ecosystem
Develops naturally without being created and maintained entirely by humans.	Created or strongly managed by humans.
Forest, pond, lake, ocean.	Crop field, aquarium, garden.
Usually has complex natural interactions.	Often requires human inputs and management.

20. Ecosystem Services

Ecosystems provide many benefits to humans, often called ecosystem services.

Service	Example
Provisioning	Food, freshwater, timber and other resources.
Regulating	Climate regulation, water purification and pollination.
Cultural	Recreation, education and cultural values.
Supporting	Nutrient cycling, soil formation and primary production.

21. Why are Ecosystems Important?

Ecosystems:

• Support biodiversity.
• Provide food and resources.
• Enable nutrient cycling.
• Support energy flow.
• Help regulate environmental conditions.
• Provide habitats for organisms.
• Support agriculture and human livelihoods.
• Provide ecosystem services.

22. What Happens When an Ecosystem is Disturbed?

Ecosystems can be disturbed by pollution, deforestation, habitat destruction, invasive species, overexploitation, climate changes and other pressures.

Disturbance can alter food webs, population sizes, nutrient cycling, habitats and ecosystem functions.

For example, removal of a predator may increase the population of its prey. This may then increase pressure on vegetation and affect other organisms.

23. Balance Between Biotic and Abiotic Components

☀️💧🌱
Abiotic Factors

↔

🌿
Producers

↔

🐇🐍🦅
Consumers

↔

🍄🦠
Decomposers

Continuous interactions maintain ecosystem processes.

24. Ecosystem and Sustainable Management

Sustainable management requires understanding ecosystem components and their interactions. Human activities should be planned so that important ecological functions and resource availability are maintained over the long term.

Ecosystem Concern	Sustainable Approach
Forest loss	Forest conservation, restoration and responsible use.
Water depletion	Efficient use, recharge and watershed management.
Soil degradation	Soil conservation and appropriate land-use practices.
Biodiversity loss	Habitat protection and conservation.
Waste accumulation	Reduce, reuse, recycle and safe disposal.

25. Important Differences

Concept 1	Concept 2	Main Difference
Biotic	Abiotic	Living vs non-living components.
Producer	Consumer	Produces organic food vs obtains food by feeding.
Consumer	Decomposer	Feeds on organisms/material vs chemically breaks down dead organic matter.
Food chain	Food web	Single feeding pathway vs interconnected pathways.
Habitat	Niche	Place where organism lives vs ecological role.
Energy flow	Nutrient cycling	Energy moves through ecosystem and dissipates; nutrients are recycled.

26. 30 MCQs with Answers

1. An ecosystem is:

A. Only a group of animals

B. Only a group of plants

C. A functional unit involving organisms and their physical environment

D. Only the non-living environment

Answer: C

2. Which is an abiotic component?

A. Temperature

B. Grass

C. Deer

D. Bacteria

Answer: A

3. Which is a biotic component?

A. Water

B. Soil

C. Sunlight

D. Fungi

Answer: D

4. Green plants are generally:

A. Decomposers

B. Producers

C. Secondary consumers

D. Tertiary consumers

Answer: B

5. The main source of energy for most ecosystems is:

A. Soil

B. Water

C. Sun

D. Minerals

Answer: C

6. Which organisms mainly act as decomposers?

A. Bacteria and fungi

B. Deer and rabbit

C. Tiger and lion

D. Grass and algae

Answer: A

7. A primary consumer generally feeds on:

A. Decomposers

B. Producers

C. Secondary consumers

D. Abiotic factors

Answer: B

8. Which is an example of an omnivore?

A. Grass

B. Deer

C. Human

D. Fungi

Answer: C

9. Which factor is abiotic?

A. Temperature

B. Bacteria

C. Grass

D. Fish

Answer: A

10. Decomposers are important because they:

A. Stop nutrient cycling

B. Produce sunlight

C. Break down dead organic matter

D. Consume only living plants

Answer: C

11. The first trophic level is occupied by:

A. Producers

B. Primary consumers

C. Secondary consumers

D. Decomposers

Answer: A

12. A rabbit in the food chain Grass → Rabbit → Snake is a:

A. Producer

B. Primary consumer

C. Secondary consumer

D. Decomposer

Answer: B

13. A food web is:

A. A single feeding pathway

B. A non-living component

C. A network of interconnected food chains

D. A type of mineral

Answer: C

14. Which component returns nutrients to the environment?

A. Producers only

B. Consumers only

C. Decomposers

D. Sunlight

Answer: C

15. Which is a natural ecosystem?

A. Aquarium

B. Crop field

C. Garden

D. Forest

Answer: D

16. Which is an artificial ecosystem?

A. Ocean

B. Aquarium

C. Natural forest

D. Natural lake

Answer: B

17. Habitat refers to:

A. The place where an organism normally lives

B. Only its food

C. Only its predators

D. Its genetic material

Answer: A

18. Niche mainly refers to:

A. The colour of an organism

B. The role of an organism in its ecosystem

C. Only the physical size of habitat

D. Only its body temperature

Answer: B

19. Which statement about energy flow is correct?

A. Energy is recycled completely

B. Energy flow is unidirectional

C. Energy flows only through decomposers

D. Energy originates from soil

Answer: B

20. Which statement about nutrients is correct?

A. Nutrients are never recycled

B. Nutrients can be recycled through ecosystems

C. Nutrients are produced by sunlight

D. Nutrients exist only in animals

Answer: B

21. Which organism is most likely a producer?

A. Algae

B. Frog

C. Snake

D. Eagle

Answer: A

22. Which is a secondary consumer in a suitable food chain?

A. Grass

B. Rabbit

C. Frog feeding on insects

D. Algae

Answer: C

23. Which process is directly associated with decomposers?

A. Photosynthesis

B. Decomposition

C. Pollination only

D. Respiration of plants only

Answer: B

24. Which ecosystem has water as its major physical medium?

A. Aquatic ecosystem

B. Desert ecosystem

C. Grassland only

D. Forest only

Answer: A

25. Which factor directly affects photosynthesis?

A. Sunlight

B. Plastic

C. Noise only

D. Glass only

Answer: A

26. Which statement is correct?

A. Consumers manufacture all their food from inorganic substances

B. Producers form an important entry point of energy into most ecosystems

C. Decomposers never affect nutrients

D. Abiotic factors are living organisms

Answer: B

27. Which one is NOT an abiotic factor?

A. Water

B. Temperature

C. Soil

D. Earthworm

Answer: D

28. A food chain usually begins with:

A. A producer

B. A tertiary consumer

C. A decomposer

D. A top predator

Answer: A

29. Which statement about a food web is correct?

A. It contains only one feeding relationship

B. It contains interconnected feeding relationships

C. It contains only producers

D. It contains no consumers

Answer: B

30. Which combination is correct?

A. Producer—grass

B. Consumer—sunlight

C. Decomposer—water

D. Abiotic—rabbit

Answer: A

27. 30 Subjective Questions with Answers

2 Marks 1. Define an ecosystem.

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

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

The two major components are biotic components and abiotic components.

2 Marks 3. What are abiotic components? Give two examples.

Abiotic components are non-living factors of an ecosystem. Examples are water and temperature.

2 Marks 4. What are biotic components?

Biotic components are living organisms present in an ecosystem, such as plants, animals and microorganisms.

2 Marks 5. Define producer.

A producer is an organism, usually a green plant or alga, that produces organic food using an external energy source such as sunlight.

2 Marks 6. Name two decomposers.

Bacteria and fungi.

3 Marks 7. Explain the role of producers in an ecosystem.

Producers manufacture organic food, usually through photosynthesis. They store energy in organic matter and provide food directly or indirectly to consumers.

3 Marks 8. Explain the role of decomposers.

Decomposers break down dead organic matter and organic wastes. They release nutrients back into the environment and help recycle matter.

3 Marks 9. Differentiate between biotic and abiotic components.

Biotic components are living organisms, such as plants and animals. Abiotic components are non-living factors, such as air, water, temperature and soil.

3 Marks 10. What are consumers? Give three examples.

Consumers are organisms that obtain organic food by feeding on plants or other organisms. Examples include deer, frog and tiger.

3 Marks 11. What is a food chain?

A food chain is a sequence of organisms through which food and energy are transferred as one organism feeds on another.

3 Marks 12. What is a food web?

A food web is a network of interconnected food chains representing multiple feeding relationships in an ecosystem.

4 Marks 13. Explain the main components of an ecosystem.

An ecosystem consists of abiotic and biotic components. Abiotic components include light, water, air, soil, temperature and minerals. Biotic components include producers, consumers and decomposers.

4 Marks 14. Explain primary, secondary and tertiary consumers.

Primary consumers feed on producers and are generally herbivores. Secondary consumers feed on primary consumers. Tertiary consumers feed on secondary consumers and occupy a higher trophic position.

4 Marks 15. Explain why decomposers are essential to ecosystems.

Decomposers break down dead organic matter, prevent its accumulation and return nutrients to the environment. These nutrients can then be taken up by producers.

4 Marks 16. Differentiate between a food chain and food web.

A food chain shows a relatively simple linear feeding pathway. A food web consists of interconnected food chains and shows multiple feeding relationships.

5 Marks 17. Describe the structure of a pond ecosystem.

Abiotic components include water, sunlight, temperature, dissolved gases and minerals. Producers include algae and aquatic plants. Consumers include zooplankton, insects and fish. Decomposers include bacteria and fungi.

5 Marks 18. Explain energy flow in an ecosystem.

Solar energy is captured by producers and transferred to consumers through feeding relationships. Some energy is lost as heat at each transfer. Therefore, energy flow through an ecosystem is unidirectional.

5 Marks 19. Explain trophic levels with an example.

Trophic level indicates feeding position. Producers are at TL1, primary consumers at TL2, secondary consumers at TL3 and tertiary consumers at TL4. Example: Grass → Rabbit → Snake → Eagle.

5 Marks 20. Explain the relationship between producers, consumers and decomposers.

Producers make food, consumers obtain food by feeding on organisms, and decomposers break down dead organic matter. Together they participate in energy transfer and nutrient cycling.

6 Marks 21. Explain all major components of an ecosystem with examples.

Abiotic components include light, water, air, soil, temperature and minerals. Biotic components include producers such as plants, consumers such as animals and decomposers such as bacteria and fungi. These components interact continuously.

6 Marks 22. Explain the importance of abiotic factors in an ecosystem.

Light provides energy for photosynthesis, water is essential for life processes, temperature affects metabolism, soil provides minerals and support, and air supplies important gases. These factors influence survival and distribution of organisms.

6 Marks 23. Explain the role of consumers in an ecosystem.

Consumers transfer energy and organic matter between trophic levels. Herbivores consume producers, carnivores consume other animals and omnivores may consume both. Their feeding relationships help regulate populations and form food chains/webs.

6 Marks 24. Explain why energy flow and nutrient cycling are different.

Energy enters most ecosystems mainly from sunlight, passes through trophic levels and is eventually dissipated as heat. Nutrients such as carbon, nitrogen and minerals are continually transferred among organisms and the physical environment and can be recycled.

6 Marks 25. Explain natural and artificial ecosystems with examples.

Natural ecosystems develop through natural processes, such as forests, lakes and oceans. Artificial ecosystems are created or strongly managed by humans, such as crop fields, gardens and aquariums.

6 Marks 26. Explain the importance of food webs.

Food webs show interconnected feeding relationships. They provide multiple pathways for transfer of energy and matter and can make an ecosystem less dependent on a single feeding relationship.

6 Marks 27. What are ecosystem services? Explain with examples.

Ecosystem services are benefits provided by ecosystems. Examples include food and freshwater, pollination, climate regulation, water purification, recreation, nutrient cycling and soil formation.

6 Marks 28. Explain how human activities can disturb an ecosystem.

Deforestation, pollution, habitat destruction, overexploitation, invasive species and other pressures can change populations, food webs, nutrient cycles and habitats. Such disturbances may reduce biodiversity and ecosystem functions.

6 Marks 29. Explain the importance of ecosystem knowledge for sustainable management.

Understanding ecosystem components helps identify resource limits, important species and ecological interactions. It allows human activities to be planned so that resource use, biodiversity and ecosystem functions are maintained over time.

6 Marks 30. Explain the complete relationship: Sun → Producers → Consumers → Decomposers → Nutrients.

The Sun supplies energy for photosynthesis. Producers convert this energy into chemical energy in organic food. Consumers obtain this food directly or indirectly. Decomposers break down dead matter and return nutrients to the environment. Producers can use these nutrients again, completing an important nutrient cycle.

28. Assertion–Reason Questions

1. Assertion: Producers occupy the first trophic level.
Reason: Producers capture energy and convert it into chemical energy stored in organic matter.

Answer: Both Assertion and Reason are true, and Reason correctly explains the Assertion.

2. Assertion: Decomposers are important for nutrient cycling.
Reason: Decomposers break down dead organic matter.

Answer: Both Assertion and Reason are true, and Reason correctly explains the Assertion.

3. Assertion: Energy flow in an ecosystem is cyclic.
Reason: Energy is completely recycled after being used by organisms.

Answer: Both statements are false. Energy flow is unidirectional and energy is dissipated as heat.

4. Assertion: Food webs contain several interconnected food chains.
Reason: Organisms can have more than one feeding relationship.

Answer: Both Assertion and Reason are true, and Reason correctly explains the Assertion.

5. Assertion: Abiotic components influence organisms in an ecosystem.
Reason: Factors such as temperature, water and light affect organism survival and growth.

Answer: Both Assertion and Reason are true, and Reason correctly explains the Assertion.

29. HOTS Questions

HOTS 1: What may happen if decomposers disappear from an ecosystem?

Dead organic matter would accumulate and nutrient recycling would be severely disrupted. Producers would eventually have less access to recycled nutrients.

HOTS 2: Why can removing one species affect several other species in a food web?

Species are interconnected through feeding relationships. Removing one species can alter food availability and population sizes of organisms that depend on it directly or indirectly.

HOTS 3: Why can a pond ecosystem become disturbed when pollutants enter the water?

Pollutants can change water chemistry, harm organisms, disrupt food chains and reduce ecosystem functions such as decomposition and nutrient cycling.

HOTS 4: Why are producers essential even though they may not be consumed directly by every animal?

Producers form the base of most food chains. Energy and organic matter reach higher consumers directly or indirectly through feeding relationships.

HOTS 5: Why is a food web generally more representative of nature than a simple food chain?

Most organisms interact with multiple species and may have several food sources or predators. A food web represents these interconnected feeding relationships more realistically.

30. One-Minute Revision

🌍 Ecosystem: Functional unit of organisms + physical environment.

☀️ Abiotic: Non-living components such as light, water, soil and temperature.

🌱 Producers: Make organic food, mainly through photosynthesis.

🐇 Consumers: Obtain food by feeding on organisms.

🍄 Decomposers: Break down dead organic matter and recycle nutrients.

🌿 TL1: Producers.

🐇 TL2: Primary consumers.

🐍 TL3: Secondary consumers.

🦅 TL4: Tertiary consumers in a simple four-level chain.

🔗 Food Chain: Linear feeding pathway.

🕸️ Food Web: Interconnected food chains.

⚡ Energy: Flows one way through an ecosystem.

♻️ Nutrients: Recycled through ecosystem processes.

31. Golden Points for CBSE Exam

1. Ecosystem = biotic components + abiotic components + interactions.

2. Producers form the first trophic level.

3. Green plants and algae are important producers in many ecosystems.

4. Consumers obtain organic food from other organisms.

5. Bacteria and fungi are major decomposers.

6. Decomposers help in nutrient recycling.

7. Food chain is a linear feeding pathway.

8. Food web is a network of interconnected food chains.

9. Energy flow is unidirectional.

10. Nutrients can be recycled.

11. Habitat means the place where an organism lives.

12. Niche refers to the ecological role and resource-use pattern of an organism.

13. Pond and forest are examples of natural ecosystems.

14. Aquarium and crop field are examples of artificial ecosystems.

15. Sustainable management requires maintaining important ecosystem functions and resources.

32. Quick MCQ Answer Key

Q	Ans	Q	Ans	Q	Ans
1	C	11	A	21	A
2	A	12	B	22	C
3	D	13	C	23	B
4	B	14	C	24	A
5	C	15	D	25	A
6	A	16	B	26	B
7	B	17	A	27	D
8	C	18	B	28	A
9	A	19	B	29	B
10	C	20	B	30	A

Class 10 CBSE Science
Our Environment and Sustainable Management | Ecosystem and Its Components
CBSE • Foundation • Competitive Preparation