Suppose individual robins with longer beaks have somewhat more offspring than those with shorter beaks and this has led to increases in beak length over time.We can say that beak size is associated with the _______ of the robin and that there is _______ selection operating on beak size.
A) fitness; stabilizing
B) fitness; directional
C) genetic structure; stabilizing
D) genetic structure; directional
E) genetic structure; disruptive

Question

Quizplus · Accepted Answer

The fact that individuals with longer beaks have more offspring suggests that beak size is positively associated with fitness. The increase in beak length over time indicates that there is directional selection, favoring individuals with longer beaks. Stabilizing selection would occur if intermediate beak sizes had the highest fitness, leading to a narrowing of the range of beak sizes over time. Disruptive selection would occur if both extreme beak sizes had higher fitness than intermediate beak sizes, leading to the divergence of beak sizes over time. However, neither of these scenarios are suggested in the given information.

Suppose Individual Robins with Longer Beaks Have Somewhat More Offspring