Question

"Two closely related species competing for the same resources cannot co-exist indefinitely and the competitively inferior one will be eliminated eventually." This statement was given by:

• A. Malthus theory of population growth
• B. Gause's competitive exclusion principle
• C. Verhulst-Pearl logistic growth
• D. Darwin's theory of natural selection

Hint:

Ecological Laws:
$\bullet$ Gause's Principle: Competitive exclusion of inferior competitor.
$\bullet$ MacArthur: Resource partitioning promotes co-existence (e.g., Warblers).
$\bullet$ Verhulst-Pearl: Logistic growth model ($K$ = carrying capacity).

Answer 1

The Correct Option is B

Concept:
Interspecific competition occurs when individuals of different species compete for shared, limiting environmental resources such as food or space.

Step 1: Defining Gause's Competitive Exclusion Principle:
Russian ecologist G.F. Gause conducted laboratory competition experiments using species of Paramecium (P. aurelia and P. caudatum).
Based on his observations, he formulated Gause's Competitive Exclusion Principle, which states that:
"Two closely related species competing for the same limiting resources cannot co-exist indefinitely, and the competitively inferior species will eventually be eliminated by the competitively superior one."
This principle holds true particularly when resources are limited.

Step 2: Evaluating Other Ecological and Evolutionary Principles:
- Malthus theory: Addressed geometric population growth outstripping arithmetic food supply.
- Verhulst-Pearl logistic growth: Described resource-limited population growth mathematically using the formula $\frac{dN}{dt} = rN\left(\frac{K - N}{K}\right)$.
- Darwin's theory of natural selection: Focused on survival of the fittest based on heritable variations.

Step 3: Conclusion:
The given statement defines Gause's competitive exclusion principle (Option B).