industrial melanism

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Industrial melanism is the change in the coloration of species that occurs as a result of industrial pollution. Increased air pollution as a result of the Industrial Revolution in Great Britain during the eighteenth and nineteenth centuries led to an accumulation of soot on many structures including tree trunks. As a result, organisms whose coloration allowed them to use the trees to hide from predators lost that advantage and were eaten more often by predators. A classic example of this was the peppered moth (Biston betularia), whose coloration is polymorphic. Prior to the Industrial Revolution, collection records indicate that the darker or melanistic form was almost unknown, but by 1895 it constituted about 98 percent of the moths collected. The two forms eventually reached a state of balanced polymorphism. Because the change in morphology could be directly linked to the change in industry, this process is described as industrial melanism.