試題詳解

9. An earthquake decimates a ground-squirrel population, killing 98% of the squirrels. The surviving population happens to have broader stripes, on average, than the initial population. If broadness of stripes is genetically determined, what effect has the ground-squirrel population experienced during the earthquake?
(A) disruptive selection
(B) a genetic bottleneck
(C) directional selection
(D) a founder event
(E) stabilizing selection