Ecosystems & Environmental Concepts MCQs

India General Knowledge

MODULE 9: Environment, Ecology & Biodiversity MCQs

Topic: Ecosystems & Environmental Concepts MCQs

Systematic Sub-Topic Structure

For clear conceptual understanding and maximum exam relevance, the MCQs are arranged in a logical and progressive sequence:

1. Basic Concepts of Ecology & Environment
2. Structure and Types of Ecosystems
3. Energy Flow, Food Chain & Food Web
4. Biogeochemical Cycles
5. Ecological Pyramids & Population Ecology
6. Environmental Balance, Stability & Sustainability

Multiple Choice Questions (MCQs)

1. Ecology is best defined as the study of:

A. Plants only
B. Animals only
C. Interaction between organisms and their environment
D. Physical environment only

Correct Answer: C

Explanation:
Ecology deals with the relationships between living organisms (biotic factors) and their surrounding environment (abiotic factors), forming the foundation of environmental science.

2. Which of the following is a biotic component of an ecosystem?

A. Soil
B. Water
C. Temperature
D. Microorganisms

Correct Answer: D

Explanation:
Biotic components include living organisms such as plants, animals, and microorganisms, while soil, water, and temperature are abiotic factors.

3. An ecosystem is best described as:

A. A biological community only
B. A physical environment only
C. Interaction of biotic and abiotic components
D. A geographical region

Correct Answer: C

Explanation:
An ecosystem consists of living organisms interacting with the physical environment, functioning as a self-sustaining unit.

4. Which is the smallest functional unit of the environment?

A. Biome
B. Biosphere
C. Ecosystem
D. Population

Correct Answer: C

Explanation:
The ecosystem is the smallest unit where living and non-living components interact and energy flow occurs.

5. Which of the following is a natural ecosystem?

A. Aquarium
B. Crop field
C. Pond
D. Garden

Correct Answer: C

Explanation:
A pond is a naturally occurring ecosystem, whereas aquariums, crop fields, and gardens are artificial ecosystems.

6. Which ecosystem has the highest biodiversity in India?

A. Desert ecosystem
B. Grassland ecosystem
C. Forest ecosystem
D. Tundra ecosystem

Correct Answer: C

Explanation:
Forest ecosystems, especially tropical forests, support the maximum species diversity in India.

7. Producers in an ecosystem are mainly:

A. Carnivores
B. Herbivores
C. Green plants
D. Decomposers

Correct Answer: C

Explanation:
Producers are autotrophs like green plants that prepare their own food through photosynthesis.

8. Which process enables producers to trap solar energy?

A. Respiration
B. Transpiration
C. Photosynthesis
D. Decomposition

Correct Answer: C

Explanation:
Photosynthesis converts solar energy into chemical energy, forming the base of all food chains.

9. Herbivores in a food chain are called:

A. Primary producers
B. Primary consumers
C. Secondary consumers
D. Decomposers

Correct Answer: B

Explanation:
Herbivores feed directly on producers and are therefore called primary consumers.

10. Which organism occupies the highest trophic level in a food chain?

A. Producer
B. Primary consumer
C. Secondary consumer
D. Top carnivore

Correct Answer: D

Explanation:
Top carnivores or apex predators occupy the highest trophic level in a food chain.

11. A food web differs from a food chain because it:

A. Has only one energy path
B. Shows multiple feeding relationships
C. Exists only in aquatic ecosystems
D. Is shorter than a food chain

Correct Answer: B

Explanation:
A food web shows interconnected food chains, providing greater ecosystem stability.

12. The 10% law of energy transfer was proposed by:

A. Darwin
B. Lindeman
C. Odum
D. Elton

Correct Answer: B

Explanation:
Raymond Lindeman proposed that only about 10% of energy is transferred from one trophic level to the next.

13. Which ecological pyramid is always upright?

A. Pyramid of numbers
B. Pyramid of biomass
C. Pyramid of energy
D. Pyramid of organisms

Correct Answer: C

Explanation:
The pyramid of energy is always upright because energy decreases at successive trophic levels.

14. Decomposers mainly include:

A. Green plants
B. Herbivores
C. Fungi and bacteria
D. Carnivores

Correct Answer: C

Explanation:
Decomposers like bacteria and fungi break down dead organic matter and recycle nutrients.

15. Which cycle involves the movement of nitrogen through the biosphere?

A. Carbon cycle
B. Oxygen cycle
C. Nitrogen cycle
D. Water cycle

Correct Answer: C

Explanation:
The nitrogen cycle involves nitrogen fixation, nitrification, assimilation, and denitrification.

16. Which gas is absorbed by plants during the carbon cycle?

A. Oxygen
B. Nitrogen
C. Carbon dioxide
D. Methane

Correct Answer: C

Explanation:
Plants absorb carbon dioxide (CO₂) during photosynthesis, playing a crucial role in climate regulation.

17. The water cycle is also known as:

A. Carbon cycle
B. Nitrogen cycle
C. Hydrological cycle
D. Biogeochemical cycle

Correct Answer: C

Explanation:
The hydrological cycle describes the continuous movement of water through evaporation, condensation, and precipitation.

18. Population density refers to:

A. Total population of a country
B. Number of species in an area
C. Number of individuals per unit area
D. Growth rate of population

Correct Answer: C

Explanation:
Population density measures how many individuals live in a given area or volume.

19. Exponential population growth is represented by:

A. J-shaped curve
B. S-shaped curve
C. Straight line
D. Circular curve

Correct Answer: A

Explanation:
In ideal conditions with unlimited resources, population growth follows a J-shaped curve.

20. Carrying capacity refers to:

A. Maximum population size an environment can support
B. Minimum population size
C. Average population
D. Population growth rate

Correct Answer: A

Explanation:
Carrying capacity is the maximum sustainable population that an environment can support.

21. Which factor limits population growth?

A. Unlimited food
B. Unlimited space
C. Environmental resistance
D. High reproduction rate

Correct Answer: C

Explanation:
Environmental resistance includes limited resources, predation, disease, and competition.

22. Succession occurring on bare rock is called:

A. Secondary succession
B. Primary succession
C. Cyclic succession
D. Retrogressive succession

Correct Answer: B

Explanation:
Primary succession begins on lifeless surfaces like bare rocks or lava flows.

23. The final stable community in ecological succession is known as:

A. Pioneer community
B. Intermediate community
C. Climax community
D. Temporary community

Correct Answer: C

Explanation:
A climax community is stable, self-perpetuating, and in equilibrium with the environment.

24. Which ecosystem service is provided by forests?

A. Pollination
B. Climate regulation
C. Soil conservation
D. All of the above

Correct Answer: D

Explanation:
Forests provide multiple ecosystem services, including climate regulation, soil protection, and biodiversity support.

25. Biodiversity refers to:

A. Variety of plants only
B. Variety of animals only
C. Variety of life forms at all levels
D. Population density

Correct Answer: C

Explanation:
Biodiversity includes genetic, species, and ecosystem diversity.

26. Which biome is characterised by very low rainfall?

A. Tropical rainforest
B. Grassland
C. Desert
D. Tundra

Correct Answer: C

Explanation:
Deserts receive less than 25 cm of rainfall annually, making them arid ecosystems.

27. Wetlands are important because they:

A. Cause floods
B. Reduce biodiversity
C. Act as natural water filters
D. Increase pollution

Correct Answer: C

Explanation:
Wetlands filter pollutants, recharge groundwater, and support rich biodiversity.

28. Which of the following is an example of an aquatic ecosystem?

A. Forest
B. Grassland
C. Pond
D. Desert

Correct Answer: C

Explanation:
A pond is an aquatic ecosystem containing freshwater organisms.

29. Ecological balance refers to:

A. Equal number of plants and animals
B. Stable interaction among ecosystem components
C. Absence of predators
D. Unlimited resource availability

Correct Answer: B

Explanation:
Ecological balance is the stable functioning of ecosystems through regulated interactions.

30. Sustainable development primarily aims to:

A. Maximise industrial growth
B. Exploit natural resources
C. Meet present needs without harming future needs
D. Stop development

Correct Answer: C

Explanation:
Sustainable development ensures environmental protection while meeting human needs, a key concept in ecology and environment studies.

✅ Exam Relevance

These Ecosystems & Environmental Concepts MCQs are highly relevant for:

• UPSC (Prelims & GS Mains – Environment)
• State PSCs (APSC, BPSC, RPSC, etc.)
• SSC, Banking & Railway Exams
• CUET & University Entrance Exams
• School & College Level Competitive Examinations across India

• Environment and ecology MCQs India

• Ecosystem concepts GK questions

• UPSC environment MCQs

• SSC ecology and environment questions

• Food chain and food web MCQs

• Biogeochemical cycles MCQs

• Biodiversity and ecosystem services MCQs

• Environmental studies GK for competitive exams

🔹 Why Ecosystems & Environmental Concepts MCQs Are Crucial for Competitive Exams

Environment, ecology, and ecosystem concepts form a core static foundation for UPSC, SSC, and State PSC examinations. Questions related to ecosystem structure, energy flow, food chains, biogeochemical cycles, biodiversity, and sustainability are repeatedly asked in both prelims and objective papers.

This MCQ set provides systematically arranged, concept-driven coverage, helping aspirants clearly understand fundamental ecological principles and confidently handle environment-related questions across all major competitive exams.

🔹 FAQ Section

Q1. Why are ecosystem concepts important for UPSC and PSC exams?

Ecosystem concepts explain how the environment functions and are essential for understanding biodiversity, climate change, and sustainability topics.

Q2. Which ecology topics are most frequently asked in exams?

Food chains, food webs, energy flow, ecological pyramids, biogeochemical cycles, succession, and biodiversity are the most asked topics.

Q3. Is ecology a static or current affairs topic?

It is mainly static but closely linked with current issues like climate change, conservation, and environmental policies.

Q4. Are these MCQs useful for SSC and Banking exams?

Yes. SSC, Banking, and Railway exams frequently ask direct questions from basic environmental and ecosystem concepts.

Q5. Who should practice Ecosystems & Environmental Concepts MCQs?

UPSC, SSC, State PSC, Banking, Railways, CUET, university entrance aspirants, and school-level competitive students should practice these MCQs.

🔹 Targeting Exams

These Ecosystems & Environmental Concepts MCQs are carefully structured to match the syllabus and difficulty level of:

• UPSC (Prelims & GS Mains – Environment & Ecology)

• State Public Service Commissions (APSC, BPSC, RPSC, MPPSC, etc.)

• SSC (CGL, CHSL, GD, MTS)

• Banking Exams (IBPS, SBI, RBI)

• Railway Exams (RRB NTPC, Group D)

• CUET & University Entrance Examinations

• School & College Level Competitive Examinations across India