You are studying a population of beetles that includes some red individuals and some yellow individuals. You know that color is a heritable trait in the population. By counting the number of red and...

You are studying a population of beetles that includes some red individuals and some yellow individuals. You know that color is a heritable trait in the population. By counting the number of red and yellow beetles over a period of 5 years, you notice that the proportion of red individuals is increasing over time while the proportion of yellow individuals is decreasing over time. How could you determine whether this is a result of natural selection? Are there other potential explanations?