Questions: Changes in the gene pool can occur due to various mechanisms. In 1989, a large oil spill occurred in Prince William Sound, Alaska, when the Exxon Valdez oil tanker ran aground. Approximately 11 million gallons of oil were spilled and spread 1,300 miles along the Alaskan coastline. The damage from the oil spill affected thousands of animals in the area, including killer whales, harbor seals, sea otters, fish, and sea birds. Which mechanism most likely affected the gene pools of the organism populations in the areas around the oil spill? genetic drift gene flow gene mutation genetic variation

The answer is the first one: genetic drift.

Explanation for each option:

1. Genetic drift: This mechanism refers to random changes in the frequency of alleles in a population's gene pool, often due to a significant reduction in population size. The oil spill likely caused a substantial decrease in the populations of affected species, leading to genetic drift as the surviving individuals' alleles became more prevalent by chance.

2. Gene flow: This mechanism involves the transfer of alleles from one population to another through migration. While gene flow can affect gene pools, it is less likely to be the primary mechanism in this scenario, as the oil spill primarily caused a reduction in population size rather than migration.

3. Gene mutation: This mechanism involves changes in the DNA sequence of an organism's genome. While mutations can introduce new alleles into a population, the immediate and significant impact of the oil spill on population sizes makes genetic drift a more likely primary mechanism.

4. Genetic variation: This term refers to the diversity of alleles within a population. While genetic variation is important for the adaptability and survival of populations, it is not a mechanism by itself but rather a result of mechanisms like mutation, gene flow, and genetic drift.

Summary: The most likely mechanism that affected the gene pools of the organism populations in the areas around the oil spill is genetic drift, due to the significant reduction in population sizes caused by the environmental disaster.