In an ecosystem, different species occupy different levels and vertical distribution of species is found. This is called _.
In an ecosystem, different species occupy different levels and vertical distribution of species is found. This is called _.
Options
Official answer
Correct option: A — Stratification
The vertical distribution of different species occupying different levels in an ecosystem is called stratification.
- For example, in a forest, tall trees form the top layer, shrubs the middle, and herbs/grasses the ground layer.
Marking scheme
- 1.1 mark: correct option A (Stratification).
- 2.Full mark for the correct choice only.
Hint
It is the technical term for vertical layers of trees, shrubs and herbs in a forest.
Quick oral answer
The vertical distribution of species at different levels of an ecosystem is called stratification, as in a forest with trees, shrubs and herbs at different heights.
Common mistakes
- 1.Choosing 'Layering' as a synonym — NCERT specifically uses the term stratification.
- 2.Confusing stratification with fragmentation, which refers to habitat breaking into patches.
- 3.Selecting 'Population', which concerns individuals of a single species, not vertical species distribution.
Analysis and explanation
Concept
Stratification is a component of the species composition and structure of an ecosystem, describing the vertical arrangement of different species at different levels.
Why A is correct
- Stratification is the NCERT term for the vertical distribution of species. In a forest, trees occupy the upper stratum, shrubs the middle, and herbs and grasses the lowest — a clear example.
Why the distractors are wrong
- Layering — a loose, informal word; not the technical term used in NCERT for this phenomenon.
- Fragmentation — habitat fragmentation is a cause of biodiversity loss (habitat breaking into patches), not vertical distribution.
- Population — a group of individuals of the same species in an area; it does not describe vertical layering of different species.
Exam trap
"Layering" sounds plausible but is not the accepted term; the examiner expects the precise word stratification.
Interesting facts
Stratification and species composition are the two main structural features of an ecosystem described in NCERT.
A tropical rainforest can show four or more distinct vertical strata — emergent, canopy, understorey and forest floor — each with characteristic species.
Question details
Q6 of 37 questions
- Board
- CBSE
- Class
- Class 12
- Subject
- Biology
- Year
- 2026
- Section
- Section A
- Marks
- 1
- Type
- MCQ
- Chapter
- Ecosystem
- Topic
- Ecosystem Structure — Stratification
- Bloom's level
- remember
- Syllabus topic
- Unit X: Ecology — Ecosystem: Structure and Function, Vertical Stratification
- Author
- CBSE
- Reviewed by
- Padhantu Academic Team
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Frequently asked questions
What is stratification in an ecosystem?
Stratification is the vertical distribution of different species occupying different levels within an ecosystem. In a forest, for example, tall trees form the top stratum, shrubs the middle, and herbs and grasses the bottom, giving a layered structure.
How is stratification different from fragmentation?
Stratification refers to the natural vertical layering of species within a habitat. Fragmentation is the breaking up of a continuous habitat into smaller isolated patches and is a major cause of biodiversity loss, not a structural feature.