The evolutionary story of moths in Engla | Class 12 Biology Chapter Evolution, Evolution NCERT Solutions

By the natural selection, industrial melanism phenomenon used to describe the evolutionary process in which light coloured peppered moth population become dark. This phenomenon affected over 70 species of moths in England, best studied in peppered moth ‘Biston betularia’. In 1800 or prior, the typical moth species had a light coloured pattern and dark coloured or melanic moths were rare. During the industrial revolution, industrial waste leads to darkened tree trunks and which killed off lichens. Then light coloured peppered moths rely on camouflage (also called cryptic colouration and is a defence or tactic that is used to disguise their appearance usually to blend in with their surroundings colour) to avoid predation and this sudden change in the environment, made them high vulnerable to predators. Over the time, light coloured moth became rare and dark one became abundant. So, by the 1886, dark coloured or melanic moths were common and thus illustrating the rapid evolutionary change. Therefore, it is reversible.

*Natural selection is the process that leads to the evolution. There are some evidences of the natural selection that have been seen in the nature like industrial melanism, evolution of drug resistant HIV.