The peppered moth is a species of moth that showcases natural selection in action. Before the industrial revolution, light-colored moths were more common as they blended in with their environment. However, as pollution darkened the landscape, dark-colored moths became more prevalent due to their camouflage. Geneticist Bernard Kettlewell confirmed this through experiments, showing that the color change was driven by the environment. Peppered moths cannot change their color individually and they are still evolving today. The peppered moth is native to Europe and North America and there are other examples of natural selection such as antibiotic resistance in bacteria and the Galapagos finches.
The Story of the Peppered Moth: A Classic Example of Natural Selection in Action
Introduction
The peppered moth (Biston betularia) is a species of moth found in Europe and North America. What makes this moth particularly fascinating is its ability to showcase the process of natural selection in action. The peppered moth’s story is often cited as one of the most well-known examples of evolutionary changes occurring over a relatively short period of time.
The Peppered Moth’s Appearance
The peppered moth has two distinct color variations: light (typically white or cream-colored) and dark (gray or black). Before the industrial revolution, the light-colored moths were much more prevalent as they could blend in with the lichens and tree bark on which they rested during the day. This provided them with excellent camouflage and protection against predators.
However, as the industrial revolution took hold, the landscape underwent significant changes. Industrial pollution led to the darkening of tree trunks and lichens, making the light-colored moths more visible and susceptible to predation. This change in their environment created an opportunity for the dark-colored moths to thrive, as they could now camouflage effectively against the newly darkened background. Natural selection favored the dark individuals, leading to an increase in their population.
Scientific Studies and Experiments
Scientists first noticed the shift in moth populations from predominantly light-colored to predominantly dark-colored in the mid-19th century. However, it wasn’t until the 1950s that extensive research was conducted to understand the genetic basis for these changes. British geneticist Bernard Kettlewell conducted a series of experiments that confirmed natural selection was indeed responsible for the shift.
Kettlewell placed light and dark-colored moth specimens on trees in polluted and non-polluted areas. The dark-colored moths were more likely to survive in polluted areas, while the light-colored moths were more likely to survive in non-polluted areas. This experiment provided concrete evidence that the changes in coloration were driven by the selective pressure imposed by the environment.
Frequently Asked Questions
1. Can peppered moths change their color?
No, individual moths cannot change their color. The coloration is determined by genetic variation within the population.
2. Are peppered moths still evolving?
Yes, peppered moths are still evolving. As the environment continues to change, the selective pressures acting on the moth population may lead to further adaptations and genetic changes.
3. Do peppered moths only exist in Europe and North America?
Yes, the peppered moth is native to Europe and North America, specifically in areas with deciduous trees where they can find suitable food sources.
4. Are there any other examples of natural selection in action?
Yes, there are several other well-documented examples of natural selection in action, such as antibiotic resistance in bacteria and the evolution of the Galapagos finches.
