Gause's principle of competitive exclusion states that:

More abundant species will exclude the less abundant species through competition.
Competition for the same resources excludes species having different food preferences.
No two species can occupy the same niche indefinitely for the same limiting resources.
Larger organisms exclude smaller ones through competition.

In ecology, the competitive exclusion principle, sometimes referred to as Gause's law of competitive exclusion or just Gause's law, is a proposition that states that two species competing for the same resource cannot coexist at constant population values, if other ecological factors remain constant. When two competing life forms attempt to occupy the same niche, only one outcome is possible: One life form will drive out the other.