Biology Forums - Study Force

In a population of parrots on an island, there is considerable variation in beak size. Parrots with small, thick beaks can efficiently eat locusts (insect), while birds with long, thin beaks can efficiently eat beetles. Both food types are available on the island. Which of the following types of selection, and effects on phenotypic variation would you expect to see?
A) Directional selection; phenotypic variation decreases.
B) Directional selection; phenotypic variation increases.
C) Disruptive selection; phenotypic variation decreases.
D) Disruptive selection; phenotypic variation is maintained.
E) Directional selection; phenotypic variation remains the same.

D