During the Industrial Revolution in England, which moth phenotype became most dominant due to natural selection?

• A. Light-colored moths during the post-Industrial Revolution period
• B. Dark-colored (melanic) moths during the post-Industrial Revolution period
• C. Both phenotypes were equally dominant throughout all periods
• D. Dark-colored (melanic) moths during the pre-Industrial Revolution period

Answer: (B)

Verified step by step guidance

1. Understand the concept of natural selection: Natural selection is the process by which organisms better adapted to their environment tend to survive and produce more offspring. Environmental changes can shift which traits are advantageous.
2. Review the historical context: During the Industrial Revolution in England, pollution from factories darkened tree bark with soot, altering the environment for organisms like moths.
3. Analyze the moth phenotypes: Light-colored moths were well-camouflaged against lichen-covered trees before the Industrial Revolution, while dark-colored (melanic) moths were more visible to predators. After the trees darkened due to soot, the dark-colored moths became better camouflaged, giving them a survival advantage.
4. Apply the principle of natural selection: The dark-colored moths had a higher survival rate in the soot-darkened environment, leading to an increase in their population over time. This is an example of directional selection, where one phenotype becomes more common due to environmental pressures.
5. Conclude the dominant phenotype: During the post-Industrial Revolution period, dark-colored (melanic) moths became the most dominant phenotype due to their improved camouflage and survival advantage in the polluted environment.