Taking an example of white-winged moths and dark-winged moths of England in per and post industrialised era, explain evolution by natural selection .

Explanation

The explanation put forth for his observation was that 'predators will spot a moth against a contrasting background'. During post industrialization period, the tree trunks became dark due to industrial smoke and soots. Under this condition, the white-winged moth did not survive due to predators, dark winged or melanished moth survived.
Before industrialisation set in, thick growth of almost white coloured lichen covered the trees-in that background the white winged moth survived but the dark coloured moth were picked out by predators. This showed that in a mixed population, those that can better adapt, survive and increase in population size.