225
MCQ Questions
40
Assertion-Reason
57
NEET 2025 Pattern
23
Previous Year Q
NCERT Mapping
Ecosystem is from NCERT Class 12 Biology, Chapter 12, under the unit Ecology. This chapter carries approximately 3% weightage in NEET, based on analysis of the last 10 years of question papers. MedicNEET covers this chapter with 322 questions — every question built from line-by-line NCERT analysis.
Topics in Ecosystem
Sample Questions — Ecosystem
Try 5 free questions below. Get all 322 in the MedicNEET app.
MCQ
In a given climate, what kind of detritus decomposes more slowly?
✅ Correct Answer: B
Detritus rich in lignin and chitin decomposes more slowly.
MCQ
Which statements are correct?
1. Producers capture only 2–10% of PAR.
2. Detritus is the raw material for decomposition.
3. Pyramid of energy can be inverted in oceans.
4. Consumers depend directly or indirectly on plants for food.
5. Humus undergoes rapid microbial decomposition.
✅ Correct Answer: A
Producers capture 2–10% of PAR. Detritus is starting material for decomposition. All consumers depend on producers. Humus decomposes very slowly. Pyramid of energy is never inverted.
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MCQ
Why are decomposers essential to ecosystem function?
✅ Correct Answer: B
Decomposers close the nutrient cycle by converting organic matter back into inorganic forms.
Assertion-Reason
Assertion (A): Humus serves as an important nutrient reservoir in soil ecosystems.
Reason (R): Humus functions as a nutrient reservoir due to its crystalline structure that binds minerals.
✅ Correct Answer: C
NCERT confirms humus serves as a nutrient reservoir (Assertion true). However, NCERT states “Being colloidal in nature it serves as a reservoir of nutrients.” The Reason falsely attributes this to crystalline structure - humus actually functions as a reservoir due to its colloidal nature, not crystalline structure. Colloidal particles have high surface area for nutrient binding.
NEET 2025 Pattern
Which of the following statements regarding the structure and function of an ecosystem are NOT correct?
S1. The species composition of an ecosystem is solely determined by the types of plants, with animal species playing a secondary role.
S2. Stratification is an example of a functional aspect of an ecosystem, illustrating the dynamics of energy transfer between trophic levels.
S3. Biotic and abiotic components interact to create a characteristic physical structure for each ecosystem, but this interaction is not crucial for its overall function.
S4. Productivity, decomposition, energy flow, and nutrient cycling are the four fundamental structural components of any ecosystem.
S5. The top vertical strata in a forest are typically occupied by herbs and grasses due to their requirement for maximum sunlight.
✅ Correct Answer: D
The question asks to identify statements that are NOT correct concerning the structure and function of an ecosystem based on NCERT text.
S1. Not correct: NCERT states, "Identification and enumeration of plant and animal species of an ecosystem gives its species composition." Therefore, species composition involves both plants and animals, and animals do not play a secondary role.
S2. Not correct: Stratification is a structural feature of an ecosystem, defined as the "Vertical distribution of different species occupying different levels." Energy transfer between trophic levels is a functional aspect (energy flow), not stratification itself.
S3. Not correct: NCERT clearly states, "Interaction of biotic and abiotic components result in a physical structure that is characteristic for each type of ecosystem." This interaction is fundamental and crucial for the ecosystem's overall function and sustainability.
S4. Not correct: Productivity, decomposition, energy flow, and nutrient cycling are listed in NCERT as the four fundamental *functional aspects* of an ecosystem, not its structural components. The structure is defined by species composition and stratification.
S5. Not correct: NCERT specifies, "trees occupy top vertical strata or layer of a forest," while "herbs and grasses occupy the bottom layers." Trees, not herbs and grasses, occupy the top strata, and they are adapted to maximum sunlight.
Since all statements (S1, S2, S3, S4, and S5) are incorrect, the correct option is D.
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Frequently Asked Questions
How many Ecosystem questions does MedicNEET have?
MedicNEET has 322 questions for Ecosystem, including 225 MCQs, 40 Assertion-Reason questions, and 57 NEET 2025-style long-form questions.
What is the NEET weightage of Ecosystem?
Ecosystem carries approximately 3% weightage in NEET, based on analysis of the last 10 years of papers. It falls under the Ecology unit of Class 12 Biology.
Are Ecosystem questions NCERT-based?
Yes, all MedicNEET Ecosystem questions are built from line-by-line analysis of NCERT Class 12 textbook. Every question maps to specific NCERT pages and concepts.