Question

Peppered moths use the adaptation of camouflage as protection from predators. They may have a variety of colors or shades, but before the Industrial Revolution, they were typically white with black speckles. The Industrial Revolution in the 1880s introduced large-scale pollution into the environment. The pollution resulted in widespread, dark-colored staining of buildings and trees.

Which of the following was the most likely effect of the Industrial Revolution on peppered moths in cities?
A.
Over time, the white, speckled moths were outnumbered by plain white moths.
B.
The population of light-colored moths decreased and the population of dark-colored moths increased.
C.
The peppered moths adapted an improved sense of sight and smell.
D.
The peppered moths developed a tolerance to smog and chemical waste.

Answer 1

B. The population of light-colored moths decreased and the population of dark-colored moths increased.

Explanation: Pollution darkened tree trunks and buildings, so dark (melanic) moths were camouflaged better and survived predation more often. Over generations natural selection increased the frequency of dark-colored moths. Options C and D describe physiological changes not supported by the classic example; A describes a shift to plain white, which is not what occurred.