In peppered moth populations, light and dark moths are selected for in different environments. Which type of selection is this, and what would a distribution curve for all peppered moths look like?

Question

1. stabilizing selection; a tall, narrow peak in the center of the graph
2. disruptive selection; a tall, narrow peak in the center of the graph
3. stabilizing selection; two peaks at the extremes of the graph with a dip in the middle
4. disruptive selection; two peaks at the extremes of the graph with a dip in the middle

Answer 1

The type of selection described in the peppered moth populations, where light and dark moths are favored in different environments, is disruptive selection. This type of selection occurs when two or more contrasting phenotypes are selected for in a population, leading to the extremes being favored over the average or intermediate forms.

Therefore, the correct answer is:

4. disruptive selection; two peaks at the extremes of the graph with a dip in the middle.

In this case, the distribution curve would show two peaks, representing the light and dark moths, with a dip in the middle for the intermediate phenotypes that are selected against.