The change of the lighter-coloured variety of peppered moth (Biston betularia) to its darker variety (Biston carbonaria)is due to

Options

A. Mutation
B. Regeneration
C. Genetic isolation
D. Temporal isolation

Answer

**Step-by-Step Solution:**

1. **Understanding the Context**: The question refers to the change in color of the peppered moth from a lighter variety (Biston betularia) to a darker variety (Biston carbonaria). This phenomenon is a classic example of natural selection and industrial melanism.

2. **Identifying the Cause**: The change in color is primarily attributed to environmental changes brought about by industrialization. Before industrialization, the environment was less polluted, and lighter-colored moths blended in with the lighter-colored trees and surroundings, making them less visible to predators.

3. **Impact of Pollution**: With the onset of industrialization, pollution increased, leading to soot and other dark materials covering the trees and the environment. This change made the lighter-colored moths more visible to predators, while the darker-colored moths had a survival advantage.

4. **Natural Selection**: As a result of this environmental change, the darker moths were more likely to survive and reproduce. Over time, the population of moths shifted towards the darker variety due to this selective pressure.

5. **Conclusion**: The change from the lighter to the darker variety of the peppered moth is due to mutation, which allowed for the genetic variation necessary for the darker coloration to exist. The process of natural selection then favored these mutations in response to environmental changes.

**Final Answer**: The change of the lighter-coloured variety of peppered moth (Biston betularia) to its darker variety (Biston carbonaria) is due to mutation and natural selection in response to industrial pollution.

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