Question

A population of rabbits has individuals with fur coloring that ranges from white to brown. The population lives in a temperate deciduous forest where the summers are mild and average about 50°F. The winters are often below freezing.

If warmer temperatures last longer into the fall and the average temperature in the winter is getting warmer, what do you expect to happen to the population?
The percentage of the population with brown fur will decrease.
The percentage of the population with white fur will decrease.
The population will increase in size, but the color percentages will remain unchanged.
The population will decrease in size, but the color percentages will remain unchanged.

Answer 1

The percentage of the population with white fur will decrease.

Explanation: Warmer, longer falls and milder winters reduce snow cover, so white fur (which camouflages rabbits in snow) becomes a disadvantage. Brown individuals will have better camouflage and higher survival/reproductive success, causing directional selection that increases brown frequency and decreases white frequency.