Question

a new pesticide has been introduced to the habitat of this population of beetles. which describes the effect of this environmental change? decreased genetic variation increased genetic variation genetic drift gene flow

Explanation:

1. Analyze the effect of pesticide introduction: A pesticide is a selective pressure. It will kill beetles that are not resistant, reducing the number of non - resistant individuals.
2. Evaluate each option:

• Option "decreased genetic variation": When a pesticide is introduced, the non - resistant beetles (with certain genetic traits) are more likely to die. This reduces the number of different genetic traits in the population, leading to decreased genetic variation.
• Option "increased genetic variation": Pesticide introduction is a selective pressure that eliminates some individuals, so it does not increase genetic variation.
• Option "genetic drift": Genetic drift is a random change in allele frequencies, usually in small populations. Here, the change is due to a selective pressure (pesticide), not randomness.
• Option "gene flow": Gene flow involves the transfer of genes between populations, which is not related to the effect of a pesticide on a single population's genetic variation.

Answer:

A. decreased genetic variation