🌍 Our Environment
Introduction to Environment and Ecosystem | Class 10 Science | CBSE + Foundation + Competitive
🌍 Our Environment | Introduction to Environment and Ecosystem
1. What is Environment? | पर्यावरण क्या है?
Environment:
Environment refers to everything surrounding an organism that affects its life, growth, survival and activities.
हिंदी: किसी जीव के चारों ओर उपस्थित वे सभी जैविक तथा अजैविक घटक जो उसके जीवन, वृद्धि, अस्तित्व और क्रियाओं को प्रभावित करते हैं, मिलकर पर्यावरण कहलाते हैं।
Environment refers to everything surrounding an organism that affects its life, growth, survival and activities.
हिंदी: किसी जीव के चारों ओर उपस्थित वे सभी जैविक तथा अजैविक घटक जो उसके जीवन, वृद्धि, अस्तित्व और क्रियाओं को प्रभावित करते हैं, मिलकर पर्यावरण कहलाते हैं।
Environment includes:
- Living organisms — plants, animals, microorganisms.
- Non-living factors — air, water, soil, temperature, sunlight, minerals.
- Interactions between living and non-living components.
2. Components of Environment | पर्यावरण के घटक
| Component | Meaning | Examples |
|---|---|---|
| Biotic Components | Living components | Plants, animals, bacteria, fungi |
| Abiotic Components | Non-living physical and chemical factors | Air, water, soil, light, temperature, minerals |
Memory Trick:
Biotic = Bio = Life → Living
Abiotic = A + Biotic → Non-living
Biotic = Bio = Life → Living
Abiotic = A + Biotic → Non-living
3. Biotic Components | जैविक घटक
Biotic components are the living organisms present in an ecosystem.
हिंदी: किसी पारितंत्र में उपस्थित सभी जीवित घटक जैविक घटक कहलाते हैं।
हिंदी: किसी पारितंत्र में उपस्थित सभी जीवित घटक जैविक घटक कहलाते हैं।
| Group | Examples |
|---|---|
| Plants | Grass, trees, crops, algae |
| Animals | Deer, tiger, birds, insects |
| Microorganisms | Bacteria, fungi, microscopic organisms |
4. Abiotic Components | अजैविक घटक
Abiotic components are the non-living physical and chemical factors of the environment.
हिंदी: पर्यावरण के निर्जीव भौतिक एवं रासायनिक घटकों को अजैविक घटक कहते हैं।
हिंदी: पर्यावरण के निर्जीव भौतिक एवं रासायनिक घटकों को अजैविक घटक कहते हैं।
Important abiotic factors include:
☀️ Sunlight
💧 Water
🌬️ Air
🌡️ Temperature
🌱 Soil
🧂 Minerals
💦 Humidity
☀️ Sunlight
💧 Water
🌬️ Air
🌡️ Temperature
🌱 Soil
🧂 Minerals
💦 Humidity
5. 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 परस्पर क्रिया करते हैं, पारितंत्र (Ecosystem) कहलाता है।
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 परस्पर क्रिया करते हैं, पारितंत्र (Ecosystem) कहलाता है।
Ecosystem = Biotic Components + Abiotic Components + Interactions
6. Examples of Ecosystem | पारितंत्र के उदाहरण
| Natural Ecosystem | Artificial Ecosystem |
|---|---|
| Forest | Crop field |
| Pond | Garden |
| Lake | Aquarium |
| River | Artificial pond |
| Grassland | Managed agricultural system |
7. Structure of an Ecosystem | पारितंत्र की संरचना
8. Producers | उत्पादक
Organisms that prepare their own food, generally through photosynthesis, are called producers.
हिंदी: वे जीव जो अपना भोजन स्वयं बनाते हैं, सामान्यतः प्रकाश संश्लेषण द्वारा, उत्पादक कहलाते हैं।
हिंदी: वे जीव जो अपना भोजन स्वयं बनाते हैं, सामान्यतः प्रकाश संश्लेषण द्वारा, उत्पादक कहलाते हैं।
Examples: Green plants, algae and certain photosynthetic microorganisms.
Role: Producers convert solar energy into chemical energy stored in food.
Role: Producers convert solar energy into chemical energy stored in food.
9. Consumers | उपभोक्ता
Organisms that depend directly or indirectly on other organisms for food are called consumers.
हिंदी: वे जीव जो भोजन के लिए प्रत्यक्ष या अप्रत्यक्ष रूप से अन्य जीवों पर निर्भर रहते हैं, उपभोक्ता कहलाते हैं।
हिंदी: वे जीव जो भोजन के लिए प्रत्यक्ष या अप्रत्यक्ष रूप से अन्य जीवों पर निर्भर रहते हैं, उपभोक्ता कहलाते हैं।
| Type | Meaning | Example |
|---|---|---|
| Primary Consumer | Feeds mainly on producers | Deer, rabbit, grasshopper |
| Secondary Consumer | Feeds on primary consumers | Frog, small fish |
| Tertiary Consumer | Feeds at higher consumer level | Snake, large predatory fish |
| Omnivore | Feeds on plants and animals | Human, bear |
10. Decomposers | अपघटक
Organisms such as bacteria and fungi that break down dead organic matter into simpler substances are called decomposers.
हिंदी: जीवाणु और कवक जैसे वे जीव जो मृत जैविक पदार्थों को सरल पदार्थों में तोड़ते हैं, अपघटक कहलाते हैं।
हिंदी: जीवाणु और कवक जैसे वे जीव जो मृत जैविक पदार्थों को सरल पदार्थों में तोड़ते हैं, अपघटक कहलाते हैं।
Importance of decomposers:
- Break down dead organisms.
- Return nutrients to the environment.
- Help maintain nutrient cycles.
- Prevent excessive accumulation of dead organic matter.
11. Food Chain | खाद्य श्रृंखला
A food chain is a sequence of organisms through which food and energy are transferred as one organism eats another.
हिंदी: जीवों की वह क्रमिक श्रृंखला जिसमें एक जीव दूसरे जीव को खाता है और भोजन तथा ऊर्जा का स्थानांतरण होता है, खाद्य श्रृंखला कहलाती है।
हिंदी: जीवों की वह क्रमिक श्रृंखला जिसमें एक जीव दूसरे जीव को खाता है और भोजन तथा ऊर्जा का स्थानांतरण होता है, खाद्य श्रृंखला कहलाती है।
Grass → Grasshopper → Frog → Snake → Eagle
The arrow generally indicates the direction of transfer of food/energy.
ध्यान दें: तीर भोजन एवं ऊर्जा के स्थानांतरण की दिशा बताता है।
ध्यान दें: तीर भोजन एवं ऊर्जा के स्थानांतरण की दिशा बताता है।
12. Food Web | खाद्य जाल
A network of interconnected food chains in an ecosystem is called a food web.
हिंदी: किसी पारितंत्र में परस्पर जुड़ी हुई अनेक खाद्य श्रृंखलाओं के जाल को खाद्य जाल कहते हैं।
हिंदी: किसी पारितंत्र में परस्पर जुड़ी हुई अनेक खाद्य श्रृंखलाओं के जाल को खाद्य जाल कहते हैं।
A food web usually provides greater stability because organisms may have more than one food source or predator relationship.
13. Trophic Level | पोषण स्तर
Each step or level in a food chain is called a trophic level.
हिंदी: खाद्य श्रृंखला में प्रत्येक चरण या स्तर को पोषण स्तर कहते हैं।
हिंदी: खाद्य श्रृंखला में प्रत्येक चरण या स्तर को पोषण स्तर कहते हैं।
| Trophic Level | Organism |
|---|---|
| First | Producers |
| Second | Primary consumers |
| Third | Secondary consumers |
| Fourth | Higher consumers |
14. Energy Flow in Ecosystem | ऊर्जा प्रवाह
Energy enters most ecosystems through sunlight and is captured by producers. It then passes from producers to consumers through food relationships.
हिंदी: अधिकांश पारितंत्रों में ऊर्जा सूर्य के प्रकाश के रूप में प्रवेश करती है। उत्पादक इसे ग्रहण करते हैं और फिर भोजन के माध्यम से उपभोक्ताओं तक ऊर्जा पहुँचती है।
हिंदी: अधिकांश पारितंत्रों में ऊर्जा सूर्य के प्रकाश के रूप में प्रवेश करती है। उत्पादक इसे ग्रहण करते हैं और फिर भोजन के माध्यम से उपभोक्ताओं तक ऊर्जा पहुँचती है।
Sun → Producers → Primary Consumers → Secondary Consumers → Higher Consumers
15. Ten Percent Law | दस प्रतिशत नियम
According to the ten percent law, approximately 10% of the energy available at one trophic level is transferred to the next trophic level.
हिंदी: दस प्रतिशत नियम के अनुसार किसी पोषण स्तर पर उपलब्ध ऊर्जा का लगभग 10% ही अगले पोषण स्तर तक पहुँचता है।
हिंदी: दस प्रतिशत नियम के अनुसार किसी पोषण स्तर पर उपलब्ध ऊर्जा का लगभग 10% ही अगले पोषण स्तर तक पहुँचता है।
Example:
1000 J → 100 J → 10 J → 1 J
This is why food chains generally do not have many trophic levels.
1000 J → 100 J → 10 J → 1 J
This is why food chains generally do not have many trophic levels.
16. Energy Pyramid | ऊर्जा पिरामिड
17. Ecosystem Balance | पारितंत्र संतुलन
An ecosystem remains functional through continuous interactions among producers, consumers, decomposers and abiotic components.
हिंदी: उत्पादकों, उपभोक्ताओं, अपघटकों और अजैविक घटकों के बीच निरंतर अंतःक्रियाओं से पारितंत्र की कार्यप्रणाली बनी रहती है।
हिंदी: उत्पादकों, उपभोक्ताओं, अपघटकों और अजैविक घटकों के बीच निरंतर अंतःक्रियाओं से पारितंत्र की कार्यप्रणाली बनी रहती है।
Example:
Plants provide food and oxygen → animals consume food → organisms die → decomposers break down dead matter → nutrients return to soil → plants use nutrients again.
18. Habitat | आवास
The specific place or type of environment where an organism naturally lives and obtains the resources needed for survival is called its habitat.
हिंदी: वह विशिष्ट स्थान या पर्यावरण जहाँ कोई जीव स्वाभाविक रूप से रहता है और जीवन के लिए आवश्यक संसाधन प्राप्त करता है, उसका आवास (Habitat) कहलाता है।
हिंदी: वह विशिष्ट स्थान या पर्यावरण जहाँ कोई जीव स्वाभाविक रूप से रहता है और जीवन के लिए आवश्यक संसाधन प्राप्त करता है, उसका आवास (Habitat) कहलाता है।
19. Population | जनसंख्या
A population is a group of individuals of the same species living in a particular area at a given time.
हिंदी: किसी निश्चित क्षेत्र में एक निश्चित समय पर रहने वाले एक ही प्रजाति के जीवों के समूह को जनसंख्या कहते हैं।
हिंदी: किसी निश्चित क्षेत्र में एक निश्चित समय पर रहने वाले एक ही प्रजाति के जीवों के समूह को जनसंख्या कहते हैं।
20. Community | समुदाय
A community consists of populations of different species living and interacting in the same area.
हिंदी: एक ही क्षेत्र में रहने वाली विभिन्न प्रजातियों की जनसंख्याओं का समूह, जो आपस में अंतःक्रिया करता है, समुदाय कहलाता है।
हिंदी: एक ही क्षेत्र में रहने वाली विभिन्न प्रजातियों की जनसंख्याओं का समूह, जो आपस में अंतःक्रिया करता है, समुदाय कहलाता है।
21. Biosphere | जैवमंडल
The part of Earth where living organisms exist and interact with the atmosphere, hydrosphere and lithosphere is called the biosphere.
हिंदी: पृथ्वी का वह क्षेत्र जहाँ जीवित जीव पाए जाते हैं और वायुमंडल, जलमंडल तथा स्थलमंडल के साथ अंतःक्रिया करते हैं, जैवमंडल कहलाता है।
हिंदी: पृथ्वी का वह क्षेत्र जहाँ जीवित जीव पाए जाते हैं और वायुमंडल, जलमंडल तथा स्थलमंडल के साथ अंतःक्रिया करते हैं, जैवमंडल कहलाता है।
22. Ecosystem Components – Quick Comparison
| Term | Definition | Example |
|---|---|---|
| Environment | Everything surrounding an organism | Air, water, plants, animals |
| Ecosystem | Functional unit involving organisms and physical environment | Pond, forest |
| Biotic | Living component | Plants, animals |
| Abiotic | Non-living component | Water, soil, temperature |
| Producer | Prepares food | Green plant |
| Consumer | Obtains food from other organisms | Deer |
| Decomposer | Breaks down dead matter | Bacteria, fungi |
23. 30 MCQs | Multiple Choice Questions
1. The environment consists of:
A. Only living organisms
B. Only non-living factors
C. Only plants
D. Living and non-living components
Answer: D
2. Which is a biotic component?
A. Water
B. Temperature
C. Plant
D. Soil
Answer: C
3. Which is an abiotic factor?
A. Bacteria
B. Water
C. Grass
D. Deer
Answer: B
4. An ecosystem is:
A. Only a group of animals
B. Only a forest
C. A functional unit involving living and non-living components
D. Only soil and water
Answer: C
5. Green plants are generally:
A. Producers
B. Primary consumers
C. Decomposers
D. Parasites only
Answer: A
6. Which organisms decompose dead organic matter?
A. Producers
B. Decomposers
C. Herbivores
D. Carnivores
Answer: B
7. A deer in a grassland is generally a:
A. Producer
B. Decomposer
C. Primary consumer
D. Tertiary consumer
Answer: C
8. A food chain represents:
A. Transfer of food and energy
B. Only water movement
C. Only oxygen production
D. Soil formation only
Answer: A
9. The first trophic level consists of:
A. Carnivores
B. Herbivores
C. Decomposers
D. Producers
Answer: D
10. The second trophic level generally consists of:
A. Producers
B. Primary consumers
C. Decomposers
D. Abiotic factors
Answer: B
11. A food web is:
A. A single food chain
B. A group of abiotic factors
C. Interconnected food chains
D. Only a plant community
Answer: C
12. The main source of energy for most ecosystems is:
A. Moon
B. Sun
C. Soil
D. Wind
Answer: B
13. Approximately how much energy is transferred to the next trophic level?
A. 10%
B. 25%
C. 50%
D. 90%
Answer: A
14. Which organism is a decomposer?
A. Tiger
B. Grass
C. Mushroom
D. Deer
Answer: C
15. Which is an artificial ecosystem?
A. Forest
B. Aquarium
C. Ocean
D. Natural lake
Answer: B
16. Which is a natural ecosystem?
A. Aquarium
B. Crop field
C. Garden
D. Forest
Answer: D
17. Organisms that prepare their own food are:
A. Consumers
B. Producers
C. Decomposers
D. Parasites
Answer: B
18. Which is NOT an abiotic factor?
A. Sunlight
B. Temperature
C. Grass
D. Water
Answer: C
19. A group of individuals of the same species in a particular area is called:
A. Population
B. Community
C. Ecosystem
D. Biosphere
Answer: A
20. A community contains:
A. Only one organism
B. Different populations interacting in an area
C. Only plants
D. Only abiotic factors
Answer: B
21. The natural place where an organism lives is its:
A. Trophic level
B. Habitat
C. Food web
D. Biosphere
Answer: B
22. Which organisms return nutrients to the environment by decomposition?
A. Producers
B. Consumers
C. Decomposers
D. Herbivores
Answer: C
23. Which is usually at the first trophic level?
A. Grass
B. Rabbit
C. Snake
D. Eagle
Answer: A
24. Which sequence represents a food chain?
A. Grass → Deer → Tiger
B. Tiger → Grass → Deer
C. Deer → Grass → Tiger
D. Soil → Tiger → Grass
Answer: A
25. Energy flow in an ecosystem is generally:
A. Circular only
B. Unidirectional
C. Completely random
D. Absent
Answer: B
26. Which component converts solar energy into chemical energy?
A. Producers
B. Carnivores
C. Decomposers
D. Soil
Answer: A
27. Which is an abiotic factor?
A. Fungi
B. Grasshopper
C. Temperature
D. Bacteria
Answer: C
28. A pond is an example of:
A. Ecosystem
B. Only population
C. Only community
D. Only habitat
Answer: A
29. The largest ecological unit among the following is:
A. Organism
B. Population
C. Community
D. Biosphere
Answer: D
30. Which statement is correct?
A. Decomposers are unnecessary in ecosystems
B. Producers depend directly on carnivores for food
C. Ecosystems contain interactions between biotic and abiotic components
D. Energy increases at every trophic level
Answer: C
24. 30 Subjective Questions with Answers
2 Marks
Q1. Define environment.
Environment is everything surrounding an organism that affects its life and activities.
हिंदी: किसी जीव के चारों ओर उपस्थित और उसके जीवन को प्रभावित करने वाले सभी घटकों को पर्यावरण कहते हैं।
हिंदी: किसी जीव के चारों ओर उपस्थित और उसके जीवन को प्रभावित करने वाले सभी घटकों को पर्यावरण कहते हैं।
2 Marks
Q2. What are biotic components?
Biotic components are the living components of an ecosystem, such as plants, animals and microorganisms.
2 Marks
Q3. What are abiotic components?
Abiotic components are non-living physical and chemical factors such as air, water, soil, light and temperature.
2 Marks
Q4. Define ecosystem.
An ecosystem is a functional unit of nature in which organisms interact with one another and with their physical environment.
2 Marks
Q5. What are producers?
Producers are organisms that prepare their own food, generally by photosynthesis. Green plants are the major producers.
2 Marks
Q6. What are consumers?
Consumers are organisms that obtain food directly or indirectly from other organisms.
2 Marks
Q7. Define decomposers.
Decomposers are organisms such as bacteria and fungi that break down dead organic matter into simpler substances.
2 Marks
Q8. What is a food chain?
A food chain is a sequence of organisms through which food and energy are transferred from one organism to another.
2 Marks
Q9. What is a food web?
A food web is a network of interconnected food chains in an ecosystem.
3 Marks
Q10. Differentiate between biotic and abiotic components.
| Biotic | Abiotic |
|---|---|
| Living components | Non-living components |
| Plants, animals, microorganisms | Air, water, soil, light, temperature |
3 Marks
Q11. Why are producers important in an ecosystem?
Producers capture solar energy and convert it into chemical energy stored in food. They form the first trophic level and provide food directly or indirectly to other organisms.
3 Marks
Q12. Write three functions of decomposers.
1. They break down dead organisms.
2. They release nutrients back into the environment.
3. They help maintain nutrient cycles and prevent accumulation of dead matter.
2. They release nutrients back into the environment.
3. They help maintain nutrient cycles and prevent accumulation of dead matter.
3 Marks
Q13. Explain trophic levels.
Each step in a food chain is called a trophic level. Producers occupy the first trophic level, primary consumers the second, secondary consumers the third and higher consumers occupy subsequent levels.
3 Marks
Q14. Give three examples of ecosystems.
Forest ecosystem, pond ecosystem and grassland ecosystem. Aquarium and crop fields are examples of artificial ecosystems.
4 Marks
Q15. Explain the structure of an ecosystem.
An ecosystem consists of biotic and abiotic components. Biotic components include producers, consumers and decomposers. Abiotic components include air, water, soil, sunlight, temperature and minerals. These components interact continuously, allowing the ecosystem to function.
4 Marks
Q16. Explain the role of decomposers in an ecosystem.
Decomposers break down dead plants, animals and organic wastes. They convert complex organic substances into simpler substances and help return nutrients to the environment. Thus, they play an essential role in nutrient cycling.
4 Marks
Q17. Explain food chain with an example.
A food chain represents the transfer of food and energy through different organisms.
Example:
Grass → Grasshopper → Frog → Snake → Eagle
Grass is the producer, grasshopper is the primary consumer, frog is a secondary consumer and higher organisms occupy higher trophic levels.
Example:
Grass → Grasshopper → Frog → Snake → Eagle
Grass is the producer, grasshopper is the primary consumer, frog is a secondary consumer and higher organisms occupy higher trophic levels.
4 Marks
Q18. What is the difference between food chain and food web?
Food Chain: A single pathway of food and energy transfer.
Food Web: A network of interconnected food chains. It represents multiple feeding relationships and is generally more complex than a single food chain.
Food Web: A network of interconnected food chains. It represents multiple feeding relationships and is generally more complex than a single food chain.
5 Marks
Q19. Explain the flow of energy in an ecosystem.
Energy enters most ecosystems from the Sun. Producers capture solar energy through photosynthesis and store it as chemical energy. Energy passes to primary consumers, then to secondary and higher consumers. At every trophic transfer, much energy is used in life processes and lost as heat, so only a small fraction is transferred to the next trophic level. Therefore, energy flow is unidirectional.
5 Marks
Q20. Explain the ten percent law with an example.
According to the ten percent law, approximately 10% of energy available at one trophic level is transferred to the next trophic level.
For example:
1000 J in producers → 100 J in primary consumers → 10 J in secondary consumers → 1 J in higher consumers.
This limits the number of trophic levels in a food chain.
For example:
1000 J in producers → 100 J in primary consumers → 10 J in secondary consumers → 1 J in higher consumers.
This limits the number of trophic levels in a food chain.
5 Marks
Q21. Explain how biotic and abiotic components interact.
Plants require sunlight, water, carbon dioxide and minerals to produce food. Animals depend on plants or other animals for food and oxygen. Decomposers act on dead organisms and return nutrients to the environment. Thus living organisms continuously interact with physical factors such as air, water, soil and temperature.
5 Marks
Q22. Differentiate between natural and artificial ecosystems.
| Natural Ecosystem | Artificial Ecosystem |
|---|---|
| Develops naturally. | Created and maintained by humans. |
| Forest, lake, river. | Crop field, garden, aquarium. |
| Generally has greater natural complexity. | Often requires human management. |
6 Marks
Q23. Describe the major components of an ecosystem.
The major components are:
1. Producers: Green plants and algae that prepare food.
2. Consumers: Herbivores, carnivores and omnivores that depend on other organisms.
3. Decomposers: Bacteria and fungi that break down dead organic matter.
4. Abiotic components: Air, water, soil, sunlight, temperature and minerals.
All these components interact to maintain ecosystem functioning.
1. Producers: Green plants and algae that prepare food.
2. Consumers: Herbivores, carnivores and omnivores that depend on other organisms.
3. Decomposers: Bacteria and fungi that break down dead organic matter.
4. Abiotic components: Air, water, soil, sunlight, temperature and minerals.
All these components interact to maintain ecosystem functioning.
6 Marks
Q24. Explain the importance of food chains and food webs.
Food chains show the pathway of food and energy transfer. Food webs show several interconnected feeding relationships. They help us understand trophic levels, energy flow and dependence among organisms. A food web can provide alternative food pathways, making many ecosystems more stable than a single isolated feeding pathway.
6 Marks
Q25. Explain the role of producers, consumers and decomposers.
Producers introduce energy into the biological system by converting solar energy into chemical energy. Consumers transfer this energy through feeding relationships. Decomposers break down dead matter and return nutrients to the environment. Together they maintain energy transfer and nutrient cycling.
6 Marks
Q26. Explain the importance of the ecosystem for living organisms.
Ecosystems provide food, water, shelter and other resources. They support energy flow, nutrient cycling, decomposition and interactions among organisms. Healthy ecosystems also contribute to soil formation, pollination, water regulation and maintenance of biodiversity.
6 Marks
Q27. Explain the relationship among habitat, population, community and ecosystem.
A habitat is the place where an organism lives. A population consists of members of the same species living in an area. Different populations together form a community. A community interacting with abiotic components forms an ecosystem.
Habitat → Population → Community → Ecosystem
Habitat → Population → Community → Ecosystem
6 Marks
Q28. Why does the amount of energy decrease at successive trophic levels?
Organisms use energy for respiration, movement, growth, reproduction and other life processes. A large portion of energy is released as heat and is not transferred to the next trophic level. Therefore only a small fraction, approximately 10% under the ten percent law, reaches the next trophic level.
6 Marks
Q29. Explain the concept of ecosystem with a suitable diagram.
An ecosystem contains biotic and abiotic components. Producers capture energy, consumers transfer it through feeding relationships, and decomposers recycle nutrients. Abiotic factors provide the physical and chemical conditions required for life.
Sun → Producers → Consumers → Decomposers → Nutrients → Producers
Sun → Producers → Consumers → Decomposers → Nutrients → Producers
6 Marks
Q30. Write a complete revision note on Introduction to Environment and Ecosystem.
Environment includes all living and non-living surroundings. An ecosystem is a functional unit where biotic and abiotic components interact. Biotic components include producers, consumers and decomposers. Abiotic components include air, water, soil, light, temperature and minerals. Producers form the first trophic level. Consumers occupy higher trophic levels. Decomposers break down dead matter and recycle nutrients. Food chains and food webs show feeding relationships. Energy enters mainly from sunlight and flows unidirectionally through trophic levels, with approximately 10% transferred to the next level.
25. Assertion–Reason Questions
Assertion (A): Green plants are called producers.
Reason (R): They can prepare food through photosynthesis.
Reason (R): They can prepare food through photosynthesis.
Answer: Both A and R are true, and R correctly explains A.
Assertion (A): Decomposers are important for ecosystem functioning.
Reason (R): They return nutrients to the environment by breaking down dead matter.
Reason (R): They return nutrients to the environment by breaking down dead matter.
Answer: Both A and R are true, and R correctly explains A.
Assertion (A): Energy flow in an ecosystem is unidirectional.
Reason (R): A significant part of energy is lost as heat at each trophic transfer.
Reason (R): A significant part of energy is lost as heat at each trophic transfer.
Answer: Both A and R are true, and R correctly explains A.
Assertion (A): Food webs are generally more complex than food chains.
Reason (R): A food web contains interconnected food chains.
Reason (R): A food web contains interconnected food chains.
Answer: Both A and R are true, and R correctly explains A.
Assertion (A): Abiotic factors are living components of an ecosystem.
Reason (R): Water and temperature are examples of abiotic factors.
Reason (R): Water and temperature are examples of abiotic factors.
Answer: A is false, but R is true.
26. HOTS | Higher Order Thinking Questions
HOTS 1: What would happen if all decomposers disappeared from an ecosystem?
Dead organic matter would accumulate, decomposition and nutrient recycling would decline, and nutrients would become less available to producers. Over time, ecosystem functioning would be seriously disrupted.
HOTS 2: Why are there usually fewer organisms at higher trophic levels?
Only a small fraction of energy is transferred to each successive trophic level. Therefore less energy is available to support organisms at higher levels.
HOTS 3: What may happen if producers in an ecosystem decline drastically?
Less food and energy would enter the food chain, affecting primary consumers and subsequently higher trophic levels.
HOTS 4: Why can a food web be more stable than a single food chain?
In a food web, organisms may have multiple food sources or feeding relationships. If one source decreases, an organism may sometimes use another available pathway.
HOTS 5: Why is sunlight important for most ecosystems?
Sunlight is the primary energy source for most ecosystems. Producers capture solar energy during photosynthesis and convert it into chemical energy stored in food.
27. Important One-Liners | परीक्षा उपयोगी तथ्य
✔ Environment = Living + Non-living surroundings.
✔ Biotic = Living.
✔ Abiotic = Non-living.
✔ Ecosystem = Biotic + Abiotic + Interactions.
✔ Producers form the first trophic level.
✔ Primary consumers are generally herbivores.
✔ Decomposers recycle nutrients.
✔ Food chain shows a feeding pathway.
✔ Food web consists of interconnected food chains.
✔ Energy flow is unidirectional.
✔ Approximately 10% energy is transferred to the next trophic level.
✔ Sun is the primary energy source for most ecosystems.
✔ Biotic = Living.
✔ Abiotic = Non-living.
✔ Ecosystem = Biotic + Abiotic + Interactions.
✔ Producers form the first trophic level.
✔ Primary consumers are generally herbivores.
✔ Decomposers recycle nutrients.
✔ Food chain shows a feeding pathway.
✔ Food web consists of interconnected food chains.
✔ Energy flow is unidirectional.
✔ Approximately 10% energy is transferred to the next trophic level.
✔ Sun is the primary energy source for most ecosystems.
28. One-Minute Revision
Environment
→ Everything surrounding an organism.
Biotic → Living components.
Abiotic → Non-living components.
Ecosystem → Biotic + Abiotic + Interactions.
Producer → Makes food.
Consumer → Obtains food from other organisms.
Decomposer → Breaks down dead matter.
Food Chain → One feeding pathway.
Food Web → Interconnected food chains.
Trophic Level → Each step of food chain.
Energy Flow → Sun → Producers → Consumers.
10% Law → Approximately 10% energy passes to next trophic level.
Biotic → Living components.
Abiotic → Non-living components.
Ecosystem → Biotic + Abiotic + Interactions.
Producer → Makes food.
Consumer → Obtains food from other organisms.
Decomposer → Breaks down dead matter.
Food Chain → One feeding pathway.
Food Web → Interconnected food chains.
Trophic Level → Each step of food chain.
Energy Flow → Sun → Producers → Consumers.
10% Law → Approximately 10% energy passes to next trophic level.
29. Concept Map | अवधारणा मानचित्र
30. Final Summary
The environment includes all living and non-living surroundings of an organism. The living components are called biotic components, while physical and chemical factors such as air, water, soil, light and temperature are abiotic components.
An ecosystem is a functional unit in which biotic and abiotic components interact. Producers, mainly green plants, introduce energy into the biological system by capturing sunlight. Consumers obtain food from other organisms, while decomposers break down dead organic matter and help recycle nutrients.
Food chains show the transfer of food and energy through trophic levels, while food webs represent interconnected food chains. Energy flow through an ecosystem is unidirectional and decreases at successive trophic levels. According to the ten percent law, approximately 10% of energy is transferred from one trophic level to the next.
Understanding environment, ecosystem, biotic and abiotic components, producers, consumers, decomposers, food chains, food webs, trophic levels and energy flow forms the foundation for the complete Class 10 Science chapter Our Environment.
🌍 Class 10 Science | Our Environment
Environment • Ecosystem • Biotic • Abiotic • Producers • Consumers • Decomposers • Food Chain • Food Web • Trophic Levels • Energy Flow
CBSE + Foundation + Competitive Preparation
Environment • Ecosystem • Biotic • Abiotic • Producers • Consumers • Decomposers • Food Chain • Food Web • Trophic Levels • Energy Flow
CBSE + Foundation + Competitive Preparation
