Which type of selection is industrial melansim observed in month, Biston betularia?

Options

A. Staibiiising
B. Directional
C. Disruptive
D. Artificial

Answer

**Step-by-Step Solution:**

1. **Understanding Industrial Melanism**: Industrial melanism is a phenomenon where darker individuals of a species become more common than lighter ones due to industrial pollution. In the case of the moth Biston betularia, the coloration of the moths changed in response to the changing environment caused by industrial activities.

2. **Identifying the Original Color**: Initially, Biston betularia moths were predominantly white. This coloration helped them blend in with the lichen-covered tree trunks.

3. **Impact of Industrialization**: As industrialization progressed, soot and pollution darkened the tree trunks. The white moths became more visible against the darkened background, making them more susceptible to predation.

4. **Survival of the Fittest**: The darker moths, which were better camouflaged against the polluted tree trunks, had a survival advantage. They were less likely to be eaten by predators, allowing them to reproduce more successfully.

5. **Directional Selection**: The change in the population from predominantly white to predominantly black moths is an example of directional selection. This type of selection occurs when one extreme phenotype (in this case, the darker color) is favored over others, leading to a shift in the population's characteristics.

6. **Conclusion**: Therefore, the type of selection observed in industrial melanism in Biston betularia is directional selection, as it favors one extreme trait (dark coloration) over the other (light coloration).

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