The peppered moth, biston betularia was generally white in color with black speckles. over time a more solid black moth became the more common variety

General
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the peppered moth, biston betularia was generally white in color with black speckles. over time a more solid black moth became the more common variety. which of the following best explains the relationship between wing pigmentation and the coloration of a moth’s surroundings?

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The Peppered Moth Phenomenon

Explanation:

The peppered moth (Biston betularia) is renowned for its remarkable adaptation known as industrial melanism, which became a classic example of natural selection in action during the Industrial Revolution in Britain. The original population of peppered moths predominantly exhibited a light coloration with speckled black markings, blending effectively with the lichen-covered bark of trees where they rested during the day. However, with the onset of industrialization, the landscape underwent significant changes due to pollution, leading to the darkening of tree trunks as a result of soot and other pollutants.

As LectureNotes mentioned, over time, a more solid black variety of the peppered moth became increasingly common. This shift in wing pigmentation from predominantly light to predominantly dark is a direct response to environmental changes brought about by industrialization. Here’s a detailed explanation of the relationship between wing pigmentation and the coloration of a moth’s surroundings:

1. Natural Selection:

  • Initially, light-colored moths had a survival advantage as they were better camouflaged against the light-colored lichen-covered bark of trees, making them less visible to predators such as birds.
  • However, as industrial pollution darkened the environment, the lighter moths became more conspicuous against the darkened tree bark, making them easier targets for predators.
  • In contrast, darker moths had a higher survival rate in polluted environments as their coloration provided better camouflage against the darkened tree trunks, thus reducing their risk of predation.

2. Genetic Variation:

  • The peppered moth population exhibited genetic variation in wing pigmentation, with some individuals being predominantly light-colored and others predominantly dark-colored.
  • Prior to industrialization, the frequency of light-colored moths was higher due to their superior camouflage against the prevalent light-colored tree bark.
  • However, as the environment changed, the frequency of dark-colored moths increased due to their enhanced survival advantage in polluted habitats.

3. Differential Reproduction:

  • With the increase in industrial pollution, the selective pressure favored the survival and reproduction of dark-colored moths over light-colored ones.
  • Dark-colored moths had a higher likelihood of surviving and reproducing in polluted environments, passing on their advantageous traits to subsequent generations.
  • Consequently, the proportion of dark-colored moths within the population increased over time, leading to a shift in the overall phenotype of the peppered moth population.

4. Evolutionary Response:

  • The observed shift in wing pigmentation from light to dark in the peppered moth population represents an evolutionary response to changes in the moth’s selective environment.
  • This phenomenon vividly illustrates Charles Darwin’s theory of natural selection, wherein heritable traits that confer a survival advantage become more prevalent in a population over successive generations.

In summary, the relationship between wing pigmentation and the coloration of a moth’s surroundings is intricately linked to natural selection and evolutionary processes. The adaptive shift in pigmentation from light to dark in peppered moths exemplifies how organisms can undergo rapid evolutionary changes in response to shifting environmental pressures.