Problem: A species of beetle lives in New York state. Some are black and some are green. In one isolated population, 10 green and 10 black beetles are living in a nearby neighborhood. The beetles are prayed upon by a species of hawk that loves to eat both green and black beetles. The hawk will randomly catch either color beetle as it is hunting. You are a beetle expert and for your research you go to this neighborhood every year to count the allele frequencies of the black beetles. To determine the frequency of black beetles, you divide the number of black beetles by the total population size (20 beetles every year). For example, if you count 7 black beetles / 20 total beetles = 0.35. Because the hawk is eating both the green and black beetles randomly, you are studying what force of evolution? genetic drift mutation natural selection gene flow