Q.99. In the field of community ecology, the lerm “competitive exclusion” refers to two species that
cannot co-exist
(A) in a community if the niches are identical.
(B) in two different communities if the niches are identical.
(C’) if the ecosystem is imbalanced.
(D) in the event of a volcanic eruption.
Competitive exclusion principle states that two species with identical niches cannot coexist in the same community, as the superior competitor will drive the other to local extinction.
Correct Answer
(A) in a community if the niches are identical. This directly matches Gause’s law, also called the competitive exclusion principle.
Core Concept
The principle arises from resource competition in limited habitats. Complete niche overlap leads to one species dominating due to even slight advantages in resource use efficiency. Species coexist only through niche differentiation or partitioning.
Option Analysis
| Option | Explanation | Correct? |
|---|---|---|
| (A) | Two species cannot occupy identical niches in the same community; one excludes the other via superior competition . | Yes |
| (B) | Applies within one community, not across separate ones where spatial separation prevents direct competition | No |
| (C) | Ecosystem balance doesn’t factor into the principle, which assumes stable resource-limited conditions | No |
| (D) | Volcanic eruptions represent disturbance, not the steady-state competition addressed by exclusion | No |
