EcosystemNEET MCQs with solutions
Ecosystem is a high-yield ecology chapter for NEET. It covers ecosystem structure (biotic + abiotic), energy flow (food chains, food webs, trophic levels), ecological pyramids, productivity (GPP, NPP), nutrient cycling (carbon, phosphorus) and ecological succession. The 10% energy transfer law and the difference between primary and secondary succession are NEET favourites.
- Class
- 12 Biology
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- 24 questions
- In the RankUp app
- 551 questions
- ELITE questions
- 269
- NCERT topics
- 15
Practise 24 questions
Tap an option to check it. Questions from every NCERT topic in this chapter, from easy to hard.
Q1Important PYQ Mixed Concepts
Which of the following is NOT a characteristic feature of an ecosystem?
Not quite — the answer is D.
An ecosystem has both biotic and abiotic components; nutrients are recycled and energy enters as solar radiation and flows unidirectionally. Energy is NOT recycled — it is progressively lost as heat at each trophic transfer. Options A, B and C are all valid characteristics; Option D is the false statement.
Q2Food Chain
Which statement best defines a food chain in an ecosystem?
Not quite — the answer is A.
A food chain is a linear sequence through which energy flows from producers to successive consumers via feeding relationships. A food web (option B) is the interconnected network, not a single chain. Nutrient cycling (option C) is a separate process.
Q3Grand Test
Which pair is INCORRECTLY matched with its role in decomposition?
Not quite — the answer is B.
Leaching involves removal of water-soluble substances from detritus into deeper soil layers; it does not form humus. Humification is the process associated with humus formation. Fragmentation, catabolism and mineralisation are correctly matched with their respective roles.
Q4Mixed Revision
Which of the following correctly represents the relationship between gross primary productivity and net primary productivity?
Not quite — the answer is B.
Gross primary productivity is total photosynthetic production by producers. After subtracting producer respiratory losses, the remaining organic matter is net primary productivity. The correct relationship is NPP = GPP minus R. Option A adds respiration incorrectly and Option C rearranges the formula wrongly.
Q5Ecosystem – Definition and Structure
Which statement best defines an ecosystem according to NCERT?
Not quite — the answer is A.
An ecosystem is defined as a functional unit of nature where living organisms interact with each other and with their physical environment. A biome is a broader unit; trophic groupings and plant-dominance criteria do not define ecosystems.
Q6Trophic Levels
Which feature of a food web makes it more stable than a single food chain?
Not quite — the answer is B.
A food web contains multiple interconnected food chains, providing alternative feeding pathways. If one species is lost, energy can still flow through alternate routes, making the system more stable than a linear food chain.
Q7Food Web
Which ecological factor most strongly increases the stability of a food web?
Not quite — the answer is B.
Greater biodiversity creates multiple alternative feeding pathways — if one species declines, consumers switch to alternatives, buffering the ecosystem. Single food source dependence (option A) maximally destabilizes a food web.
Q8Nutrient Cycling
Which ecological process describes the circulation of chemical elements between organisms and the physical environment?
Not quite — the answer is A.
Nutrient cycling is the movement of elements through biotic and abiotic components; biogeochemical cycling is a synonym but nutrient cycling is the term NCERT uses for this definition specifically.
Q9Components of Ecosystem
Which group of organisms forms the autotrophic component of an ecosystem?
Not quite — the answer is A.
Producers are autotrophs that synthesise organic food from inorganic substances using solar energy. Herbivores and carnivores are heterotrophs; decomposers are heterotrophs that act on dead matter.
Q10Ecological Pyramids
Which ecological pyramid represents the number of organisms at each trophic level?
Not quite — the answer is A.
Pyramid of numbers counts individual organisms at each trophic level. Pyramid of biomass measures dry mass, not count. Pyramid of energy measures rate of energy flow per unit area per unit time.
Q11Productivity
Which component of productivity represents the total energy captured by producers during photosynthesis before any losses?
Not quite — the answer is B.
GPP is the total rate of photosynthesis including all energy fixed before respiratory losses. NPP = GPP − Respiration, so NPP is always less than GPP.
Q12Decomposition
Which ecological process converts complex organic matter into simpler inorganic substances?
Not quite — the answer is A.
Decomposition converts dead organic matter into inorganic substances via microbial activity. Respiration releases energy from living cells — it is not the same as decomposition of dead matter.
527 more questions on this chapter are waiting in the app
Every one with a detailed explanation, plus flashcards and chapter tests.
Get RankUp on Google PlayQ13Ecological Succession
Which ecological process describes gradual and predictable change in species composition over time?
Not quite — the answer is A.
Ecological succession is the orderly, directional change in community structure and species composition over time. Nutrient cycling and energy flow are ongoing processes, not directional community change.
Q14Energy Flow
Which law states that only about 10% of energy is transferred from one trophic level to the next?
Not quite — the answer is B.
Lindeman's ten percent law states that only ~10% of energy at one trophic level is transferred to the next. Liebig's law refers to nutrient limitation, not energy transfer.
Q15Integrated Ecosystem Concepts
Which ecosystem component converts solar energy into chemical energy supporting all trophic levels?
Not quite — the answer is A.
Producers fix solar energy via photosynthesis into organic molecules, forming the base of all energy flow. Decomposers recycle nutrients but do not fix solar energy.
Q16Ecosystem – Definition and Structure
Interaction between organisms and their physical environment in an ecosystem primarily results in which two ecological processes?
Not quite — the answer is B.
NCERT explicitly states that interactions between biotic and abiotic components result in energy flow and nutrient cycling. Evolution and population growth are consequences of other ecological dynamics, not the primary outcome of organism–environment interaction.
Q17Ecosystem – Definition and Structure
Which feature best represents the structural aspect of an ecosystem?
Not quite — the answer is C.
Ecosystem structure refers to the arrangement and composition of living and non-living components. Energy transfer rate and decomposition speed are functional aspects; biogeochemical cycling is also a function, not structure.
Q18Ecosystem – Definition and Structure
Which feature primarily represents the functional aspect of an ecosystem?
Not quite — the answer is D.
Ecosystem function refers to ecological processes — principally energy flow and nutrient cycling. Stratification, soil type, and species count are structural features describing what components are present, not what processes operate.
Q19Ecosystem – Definition and Structure
Which of the following correctly explains why ecosystem structure and function are inseparable?
Not quite — the answer is B.
NCERT treats structure (components) and function (processes) as interlinked: the identity and arrangement of biotic and abiotic components directly determines the ecological processes — energy flow and nutrient cycling — that occur. Separating them is conceptually incorrect.
Q20Ecosystem – Definition and Structure
Which component of ecosystem structure includes temperature, light, and water?
Not quite — the answer is B.
Abiotic components encompass all physical and chemical factors — temperature, light, water, soil, wind — that constitute the non-living environment. Community refers strictly to biotic (living) components.
Q21Ecosystem – Definition and Structure
Which example correctly represents a natural ecosystem?
Not quite — the answer is C.
A forest develops and self-regulates without direct human management, making it a natural ecosystem. Aquaria, botanical gardens, and crop fields are artificial ecosystems maintained through sustained human intervention.
Q22Ecosystem – Definition and Structure
Which statement about ecosystem boundaries is most accurate according to NCERT?
Not quite — the answer is D.
NCERT explicitly notes that most ecosystems do not have sharply defined boundaries — transition zones (ecotones) exist where adjacent ecosystems overlap. The idea of strict, fixed borders applies to artificial or human-defined units, not natural ecosystems.
Q23Ecosystem – Definition and Structure
Which observation best indicates that an ecosystem is dynamic rather than static?
Not quite — the answer is B.
Ecosystems are dynamic because energy flows unidirectionally and nutrients cycle continuously among biotic and abiotic components. Constant energy fixation rate or unchanged species composition would suggest stasis, not dynamism.
Q24Ecosystem – Definition and Structure
Which of the following is an example of an artificial ecosystem created and maintained by humans?
Not quite — the answer is A.
NCERT lists crop fields (agro-ecosystems) and aquaria as examples of man-made artificial ecosystems. Tropical rainforests, coral reefs, and alpine grasslands are natural ecosystems that develop without sustained human management.
ELITE question · AIR under 50 level
This chapter has 269 ELITE questions for students aiming at the very top. They are only in the app.
Unlock ELITE questions in the appKey Ecosystem Facts
Quick revision: most questions in this chapter test these facts.
| Concept | Key Fact |
|---|---|
| Energy flow | Unidirectional; 10% law (Lindeman) — only 10% energy passes to next trophic level |
| GPP vs NPP | GPP = total photosynthesis; NPP = GPP − Respiration (available to consumers) |
| Pyramid of energy | Always upright; pyramid of biomass inverted in aquatic (phytoplankton < zooplankton) |
| Decomposition | Fragmentation → leaching → catabolism → humification → mineralisation |
| Carbon cycle | Atmosphere ↔ biosphere via photosynthesis and respiration; fossil fuels add CO₂ |
| Ecological succession | Primary (bare rock → lichens → mosses → herbs → shrubs → trees); secondary (disturbed area) |
What the app covers in this chapter
551 questions in total, each with a detailed explanation.
| Important PYQ Mixed Concepts | 82 |
| Food Chain | 60 |
| Grand Test | 55 |
| Mixed Revision | 55 |
| Ecosystem – Definition and Structure | 40 |
| Trophic Levels | 40 |
| Food Web | 40 |
| Nutrient Cycling | 40 |
| Components of Ecosystem | 21 |
| Ecological Pyramids | 20 |
| Productivity | 20 |
| Decomposition | 20 |
| Ecological Succession | 20 |
| Energy Flow | 19 |
| Integrated Ecosystem Concepts | 19 |
Questions students ask
Is Ecosystem important for NEET?
Very important — energy flow, ecological pyramids, productivity and succession are tested almost every year. The 10% law and GPP/NPP distinction are especially common.
Which topics should I revise first?
Focus on the 10% energy transfer law, GPP vs NPP, types of ecological pyramids (when inverted), steps of decomposition, carbon and phosphorus cycles, and primary vs secondary succession.
How many questions from this chapter are on RankUp?
The RankUp app has 551 questions on Ecosystem, including 269 ELITE questions written for students aiming at AIR under 50. Every question has a detailed explanation.
