You have studied the story of Pepper mot | 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, in 1886, light coloured moth became rare and dark one became abundant.

This leads to better chances of survival of dark winged moths and this shows reversible evolution. When the industries have removed, it will help in bringing down population level. And, this will help in to bring the lichens population again flourish on the tree trunks and then tree trunks will gain a whitish layer of lichens which will result in surviving the more population of white- winged moths.