After large seeds became more common, the average beak size of the medium ground finch increased in size over the course of a few years. This change was most likely a case of
A) disruptive selection.
B) directional selection.
C) stabilizing selection.
D) genetic drift.

Question

Quizplus · Accepted Answer

Directional selection occurs when there is a shift in the average value of a trait in a population over time. In this case, the average beak size of the medium ground finch increased in size over the course of a few years. This is most likely due to directional selection, as there was a selective advantage for birds with larger beaks to be able to crack open the larger seeds that became more common.

After Large Seeds Became More Common, the Average Beak Size