Question

A very small population of fruit flies becomes isolated on an island with a novel kind of fruit that they have never before encountered. It is the only potential food source on the island. If, after ten generations, genotype frequencies of this island fruit fly population are not in Hardy-Weinberg Equilibrium we might conclude that: Choose all that apply.

A. There has been evolution by natural selection favoring flies that are adapted to the novel fruit source.
B. There has been gene flow in the small population.
C. There has been genetic drift in the small population.
D. There is insufficient gene flow for genetic divergence to take place.

Answer 1

If the fruit fly population's genotype frequencies are not in Hardy-Weinberg Equilibrium, we can infer there has been evolution by natural selection and genetic drift in the isolated population. Therefore, the correct option is A, C.

Step-by-step explanation:

If, after ten generations, genotype frequencies of this island fruit fly population are not in Hardy-Weinberg Equilibrium, we might conclude that:

A. There has been evolution by natural selection favoring flies that are adapted to the novel fruit source.

C. There has been genetic drift in the small population.

Option B, which suggests there has been gene flow in the small population, is less likely if the population is isolated. Option D is incorrect because it states there is insufficient gene flow for genetic divergence to take place, which contradicts the premise of isolation and lack of Hardy-Weinberg Equilibrium.