The peppered moth has typically white-coloured wings, finely speckled with black. But in the first half of the 19th century, virtually all peppered moths had entirely black wings -- the result of a mutation. This sudden and dramatic change was related to the growth of industries and, therefore, of pollution, as the industrial revolution gathered momentum. It was observed that the moths did not turn black in rural areas, which had remained free of pollution.
The peppered moth offers one such example of organisms acquiring new forms as a result of increasing pollution. As the environment changed, white moths were at a sudden disadvantage in urban areas as small insect-feeding birds, searching tree trunks for food, found and ate the moths, which did not match the dark tree trunks on which they rested. Black moths increased in frequency as a result of natural selection by these birds. This shows that under one type of environmental condition a particular adaptation was an advantage (white winged moth did not stand out in an unpolluted background) and with changing conditions the changed adaptation was an advantage (black winged moth could not be spotted on a polluted background). This shows that for survival in changing climatic conditions, species have to bring about a change in themselves too.
Today, in European cities and in Britain, 98 per cent of peppered moths are black in areas of heavy industry, such as Manchester, while in rural areas, such as Cornwall, all the moths have the original white forms.