A population of snakes lives in a valley. This population of snakes is 30% black and 70% brown in coloration. A dam is built to flood part of the valley, separating the snakes into two populations. West of the human-made lake, there's a very small population of all black snakes, while east of the lake, the population is much larger and retains the same percentage of black and brown coloration as before the dam was built. What process applies to this example?

Question

Quizplus · Accepted Answer

This is an example of genetic drift, which is the random fluctuation of allele frequencies in a population due to chance events. The small population of all black snakes west of the lake is a result of genetic drift, as the small sample size caused a random decrease in the frequency of brown alleles, resulting in a population of only black snakes. The larger population of black and brown snakes east of the lake is not affected by genetic drift since it retains the same percentage of black and brown coloration as before.

A Population of Snakes Lives in a Valley