What is the essence of Gause's principle of competitive exclusion?

Two species cannot occupy the same niche indefinitely when competing for the same limited resources.

The correct answer is Option (2)-Two species cannot occupy the same niche indefinitely when competing for the same limited resources.

Gause's "Competitive Exclusion Principle" states that when two closely related species compete for the same resources, they cannot coexist indefinitely, and the species that is competitively inferior will eventually be eliminated. However, more recent studies suggest that such generalizations about competition are not always accurate, as they do not consider the complexity of ecological interactions.

While it is true that competition can lead to exclusion when resources are limited, recent studies have highlighted that species facing competition can evolve mechanisms that promote coexistence rather than exclusion. One such mechanism is "resource partitioning," where competing species divide or specialize in their resource use to reduce direct competition.

For example, in the case of the five closely related species of warblers studied by MacArthur, they were able to coexist on the same tree by exhibiting behavioral differences in their foraging activities. By choosing different times for feeding or adopting different foraging patterns, they effectively partitioned the resources and reduced direct competition.

These studies emphasize that competition does occur in nature, but its outcomes can be influenced by various factors, including evolutionary adaptations and resource partitioning. Rather than assuming that exclusion is inevitable, these studies highlight the potential for species to evolve strategies that allow for coexistence and reduce competition.

In summary, recent research challenges the strict interpretation of Gause's Competitive Exclusion Principle and suggests that species facing competition can evolve mechanisms, such as resource partitioning, that enable coexistence rather than exclusion. This highlights the complexity of species interactions and the potential for diverse strategies to promote coexistence in nature.