Question

which graph best represents disruptive selection?
graph a: has a plot with \original population\ (blue) and \population after selection\ (red) with two peaks and a valley in between, labeled with \proportion of individuals\ on y - axis and \trait value\ on x - axis.
graph b: has a plot with \original population\ (red) and \population after selection\ (blue), where the blue curve is shifted to the right, labeled with \proportion of individuals\ on y - axis and \trait value\ on x - axis.
graph c: has a plot with \original population\ (blue) and \population after selection\ (red), where the red curve is narrower and centered, labeled with \proportion of individuals\ on y - axis and \trait value\ on x - axis.
done

Explanation:

Step1: Recall Disruptive Selection

Disruptive selection favors extreme traits, splitting the population into two groups (bimodal distribution), reducing intermediate traits.

Step2: Analyze Each Graph

• Graph A: After selection, two peaks (extremes) and a valley (intermediates reduced) → matches disruptive selection.
• Graph B: After selection, one peak shifted (directional selection).
• Graph C: After selection, peak narrower (stabilizing selection).

Answer:

Graph A