Question

However, in the nineteenth century, it was noticed that in towns and cities it was actually the melanic form of the moth that was more common than the pale peppered form. Industrialization and domestic coal fires had caused sooty air pollution which had killed off lichens and blackened urban tree trunks and walls. Now it was the pale form of the moth that was more obvious to predators, while the melanic form was better camouflaged and more likely to survive and produce offspring. As a result, over successive generations, the melanic moths came to outnumber the pale forms in our towns and cities. Since moths are short-lived, this evolution by natural selection happened quite quickly. For example, the first melanic Peppered Moth was recorded in Manchester in 1848 and by 1895 98% of Peppered Moths in the city were melanic.

What variation of moths was favored after the Industrial Revolution? Justify your answer using evidence from the paragraph above.

Answer 1

Answer

• The evolution of the peppered moth is an evolutionary instance of directional colour change in the moth population as a consequence of air pollution during the Industrial Revolution. The frequency of dark-coloured moths increased at that time, an example of industrial melanism.

• Later, when pollution was reduced, the light-coloured form again predominated. Industrial melanism in the peppered moth was an early test of Charles Darwin's natural selection in action, and remains as a classic example in the teaching of evolution