The peppered moth provides a well-known example of natural selection. The light-colored form of the moth was predominant in England before the industrial revolution. In the mid-nineteenth century, a dark-colored form appeared. The difference is produced by a dominant allele of one gene. By about 1900, approximately 90% of the moths around industrial areas were dark-colored, whereas light-colored moths were still abundant elsewhere. Apparently, birds could readily find the light moths against the soot-darkened background in industrial areas and therefore were eating more light moths. Recently, the use of cleaner fuels has greatly reduced soot in the landscape, and the dark-colored moths have been disappearing. Should the two forms of moths be considered separate species?

This is a common example of industrial melanism that occur in peppered moth where change in their color takes place due to industrial revolution. The moths are not separate but are same species.

Explanation:

Before industrial revolution, the color of moth was black that were found in the Manchester. The light bodied moths are capable of blend in the light which is not done by black colored moth thus they were eaten by birds and the population of light color moth increases.

When industrial revolution occur, the light color lichens died from sulfur dioxide and thus tree color became darker which led to increase eating of light color moth by the predatory birds as they were unable to blend in the environment and on the other hand, the population of black color moth increases as they can easily camouflaged in the environment.