Question

Explain Gause’s competitive exclusion principle.

Hint:

A catchy way to remember this is: "Two species cannot live in the same house if they want to eat the exact same food at the exact same time."
Coexistence is only possible through niche differentiation or resource partitioning.

Answer 1

Step 1: Understanding the Concept:
In community ecology, the "niche" of a species includes all the resources it uses and the conditions it requires.
When two species have significantly overlapping niches—meaning they require the same limited resources like food, nesting sites, or sunlight—competition arises.
Russian ecologist G.F. Gause formulated a principle to describe the outcome of such intense competition.
Step 2: Detailed Explanation:
The principle is built on several key ecological premises:
1. Resource Limitation: The principle is most applicable when resources are "limiting" (not enough to satisfy everyone).
2. Absolute Competitors: If two species are identical in their resource requirements, they are termed "complete competitors."
3. The Outcome of Competition: One species will always possess a slight biological advantage—be it faster reproduction, better foraging efficiency, or higher tolerance to environmental stress.
4. Competitive Exclusion: Over time, the "superior" competitor will out-reproduce the "inferior" one.
5. Extinction: This leads to the eventual local extinction of the inferior species or forces it to migrate to a different habitat.
6. Modern Context (Resource Partitioning): Later studies (like MacArthur's warblers) showed that species can avoid this exclusion by evolving "Resource Partitioning," where they feed at different times or on different parts of the same resource to coexist.
Step 3: Final Answer:
Gause’s principle asserts that in a resource-limited environment, two species cannot occupy the exact same niche; the more efficient species will eventually displace the other.