Question

Why is it that two species cannot occupy the same niche for an extended period of time?

Answer 1

Answer:

In terms of ecology a niche can be defined as role or function an organisms play within the ecosystem. A niche represent the interaction of an organism with the living and non living components of the ecosystem. It is represented by predator-prey relationships, parasitic and mutualistic properties and other functions. The two species cannot occupy the same niche for an extended period of time, this can be explained by competitive exclusion principle. According to this principle, no two species can have the same ecological niche. The two or more species competing for the same resource in an ecosystem the one species having more favorable adaptations will be able to thrive resources better than others. Therefore, this  will result in the decrease in abundance, migration and extinction of weak and less competitive species.

Answer 2

A niche is a specie's function in its habitat or its level on the food chain, so two species competing at the same level for the same food and habitat eventually one species will have to migrate or starve due to lack of food.