Question

Understand the competitive exclusion principle:

a) Two species with identical niches can coexist indefinitely
b) Competition between species always leads to the exclusion of one species
c) Species with different niches cannot coexist
d) The principle only applies to plants

Answer 1

The Competitive Exclusion Principle posits that two species cannot coexist indefinitely when they compete for the exact same resources, leading to the extinction or niche differentiation of one species.

Step-by-step explanation:

The Competitive Exclusion Principle is an ecological theory which suggests that two species competing for the exact same resources cannot coexist at constant population values, if other ecological factors remain constant. When two species have the same ecological niche, they attempt to occupy the same habitat and utilize the same resources, leading to interspecific competition. Over time, the competition will result in the extinction of the less adapted species or to an evolutionary or behavioral shift towards a different ecological niche in one or both of the species.

An empirical example of this principle was observed with two protozoan species, Paramecium aurelia and Paramecium caudatum. When in the same environment, the former outcompetes the latter for resources, leading to the extinction of Paramecium caudatum. This demonstrates that a stable coexistence is likely only possible if species have different niches that allow them to avoid direct competition for resources.