Explain the action of natural selection with reference to industrial melanism

Explanation

(1) Natural selection in action is best described by the example of industrial melanism.
(2) This phenomenon was first described by Kettlewell in U.K.
(3) He observed the development of dark coloured peppered moths (Biston carbonaria), in response to air pollution during the industrial revolution in U .K.
(4) The dark coloured moths were developed as a result of random mutation.
(5) Before the industrial revolution light coloured peppered moths (Bis ton betularia) were abundant.
(6) These peppered moths were nocturnal in habit and during daytime they rested on the tree trunk.
(7) Their pale body colour camouflaged with the surrounding tree barks which were covered with lichen. This camouflage helped them to escape from the predatory birds. On the other hand, the black coloured moths resting on pale tree bar ks were very conspicuous and thus killed by the predatory birds. Their numbers were gradually reduced.
(8) However, after industrial revolution, the surrounding changed. In changed conditions melanic forms were at evolutionary advantage and hence the B. betularia were fast replaced by B. carbonaria.