dark winged moth where as it reversed in the post industrialised period In Pre industrialised period the tree trunks were covered with white coloured thick growth of lichens hence the light coloured moth were not spotted by the predator and their number increased , where as the dark coloured moths were captured and their numbers decreased During post industrialisation period the tree trunks became dark due to industries smoke and hence the dark coloured moths were not captured by the predators and their number increased where as the light coloured moths were captured and their number decreased In a mixed population those moths that are better adapted camouflaged to the changed environment survive and increase in population size
