Following the Industrial Revolution, there was a dramatic change in the coloring of moths near the town of Manchester, England,
in the 1850s. There were many factories in Manchester that released dark soot and pollution into the air and forests nearby. In
the 1950s, the government put air quality control measures into place. The graph shows the percent of each color variation of
peppered moths over time.
Peppered Moth Population
of Manchester
Light
moth
100%
80%
60%
40%
Dark
moth
Dark moth
Light moth
20%
0%
1850
1950
2000
1900
Year
Which statement best describes why the frequencies of dark and light peppered moths changed?
A. Pollution from the factories resulted in the widespread death of both light-colored and dark-colored moths.
B. Soot from the factories darkened trees, making dark moths harder to see and less vulnerable to predation.
C. Emissions from the factories made the sky dark, so the moths changed color to be better hidden during flight.
D. Greenhouse gases from the factories made the surrounding areas warmer, favoring light moths that reflect heat more easily.
Percent of
Population