How are moths turning from light colored to dark colored an example of natural selection.
The phenomenon of moths turning from light-colored to dark-colored represents an example of industrial melanism, which is an example of natural selection. Natural selection is the process by which certain traits become more or less common in a population over time, based on their impact on an organism's survival and reproductive success.
In the case of moths, industrial melanism refers to the adaptation of their coloration in response to environmental changes caused by human industrialization. Before industrialization, most moths had light-colored wings, which helped them blend in with the tree bark and avoid predators during the day. However, with the advent of pollution and the resulting blackening of tree trunks, light-colored moths became more conspicuous and prone to predation.
In this altered environment, a small population of moths exhibited genetic variations that resulted in darker coloration. These darker moths had a better chance of surviving and reproducing because their coloration allowed them to blend in with the newly darkened tree bark, making them less visible to predators. Over time, the darker coloration became more common in the moth population as these individuals were more successful at passing on their genes to subsequent generations. This change in wing coloration is a classic example of natural selection, as the environment (polluted trees) exerted selective pressure that favored moths with a specific trait (darker wings).
Natural selection acts upon heritable variations within a population and leads to the adaptation of organisms to their environment over generations. The industrial melanism in moths demonstrates how such adaptations can occur within a relatively short time span due to changes introduced by human activities.