An earthquake decimates a ground-squirrel population, killing 98 percent 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) directional selection
B) disruptive selection
C) a founder event
D) a genetic bottleneck
E) gene flow

Question

Quizplus · Accepted Answer

The earthquake caused a drastic reduction in the ground-squirrel population, killing 98% of the squirrels. This led to a genetic bottleneck, in which the surviving population is likely not representative of the initial population in terms of genetic variation. The fact that the surviving population has, on average, broader stripes suggests that there may have been selection for this trait during the bottleneck, as individuals with broader stripes may have had a better chance of survival. However, without more information about the genetic basis of stripe broadness and the specific selective pressures at play, it is difficult to say for certain what type of selection (if any) was operating.

An Earthquake Decimates a Ground-Squirrel Population, Killing 98 Percent of the Squirrels