Q6
1 markMCQSection A

In an ecosystem, different species occupy different levels and vertical distribution of species is found. This is called _.

Ecosystem
Ecosystem Structure — Stratification

Options

(A)Stratification
(B)Layering
(C)Fragmentation
(D)Population
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.
stratificationvertical distributionecosystem structurespecies compositionforest layerstrophic levelstrees shrubs herbs

Marking Scheme

  • 11 mark: correct option A (Stratification).
  • 2Full 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.

Analysis & 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.

Common Mistakes

  1. 1Choosing 'Layering' as a synonym — NCERT specifically uses the term stratification.
  2. 2Confusing stratification with fragmentation, which refers to habitat breaking into patches.
  3. 3Selecting 'Population', which concerns individuals of a single species, not vertical species distribution.

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.

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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.