Question

Peppered Moths

Before the Industrial Revolution there were more sightings of light-colored moths and
fewer sightings of dark-colored moths. As factories were built during the Industrial
Revolution, pollution increased. At this time, scientists observed that the number of
light-colored moths decreased, while the number of dark-colore moths increased and
became more abundant in the population than the light-colored variety.
Which graph represents how natural selection acted on moth coloration during
the Industrial Revolution? The dotted line represents the original population and the
solid line represents the population after selection.

Answer 1

The correct answer is - Option B.

Step-by-step explanation:

Before the Industrial Revolution, the light color moths were predominant so that they can blend in with the light-colored trees and lichens in their environment. After releasing coal smoke from factories, the trees became darkened, and the light-colored moths become an easy target for predator birds to spot.

Over time, the frequency of the dark moth increased due to they had a higher survival rate in habitats affected by the air pollution and it blends with darker coloration blended with the sooty trees. This is a shift in the population’s genetic variance toward the new, phenotype.

In graph B, light color moth frequency decreases, and after natural selection increases over time and after a decrease in evolution the dark color again decreases.