evolution short essay

Short Essay:

Most rock pocket mouse populations have sandy-colored fur, which is consistent with the light color of the desert rocks and sand on which they live. On the other hand, dark-colored rock pocket mouse populations have been found living on black, basaltic rock formations caused by geologic lava flows. What is the best explanation for these facts?

Include the following words or phrases in your short essay: mutation, survival of the fittest, natural selection, geology drives biology.

A short essay maybe about 1-2 paragraphs.