Question

In the case of the English peppered moth, which of the following occurred?

Options

• Bird predation was probably an important factor in natural selection.

• Soot incorporated into the moths resulted in industrial melanism.

• Dark moths were unknown before pollution.

• Natural selection produced new genes adapted to the darkened landscape.

Answer 1

Soot incorporated into the moths resulted in industrial melanism.

Explanation:

In the case of the English peppered moth, before industrial pollution, the light-colored (grey) moth was common because it was well camouflaged against lichen-covered trees, while the darker (melanic) form was rare. With the Industrial Revolution, soot blackened tree trunks, making dark moths less visible to predators (mainly birds) and light moths more visible and thus more preyed upon. As a result, the population shifted toward dark-colored moths, a phenomenon known as industrial melanism. This shift was driven by selection for the better-camouflaged moth form by bird predation. The soot did not get incorporated into the moths, nor did natural selection produce new genes; rather, the frequency of pre-existing genetic variants changed due to differential survival caused by predation. Dark moths were also present in low numbers before pollution, not entirely unknown.