Question

Which one of the following is potentially explained by the mid-domain effect?

• A. Increase in body size of mammals at high latitudes
• B. Species richness along an elevational gradient
• C. Cumulative species richness with increasing area
• D. Species richness along a disturbance gradient

Hint:

The mid-domain effect is often observed when species richness peaks in the middle of a gradient, as it is where the most overlap in species ranges occurs.

Answer 1

The Correct Option is B

Step 1: Understand the mid-domain effect.
The mid-domain effect refers to the phenomenon where species richness is highest in the middle of a geographic domain (such as along an elevational gradient) because there are more species that can coexist in these intermediate regions.
Step 2: Explanation of other options.
- (A) The increase in body size of mammals at high latitudes is explained by Bergmann’s rule, not the mid-domain effect.
- (C) Cumulative species richness with increasing area is explained by the species-area relationship, not the mid-domain effect.
- (D) Species richness along a disturbance gradient is explained by the disturbance hypothesis, not the mid-domain effect.
Step 3: Conclusion.
The mid-domain effect best explains species richness along an elevational gradient, as species are more likely to coexist in the middle range of the gradient.