Question

a population of snakes that eat small rodents enters a new habitat. in the new habitat, there are many species of rodents, and their populations are high because there are few natural predators. what will most likely be the effect on the genetic variation of the snake population?
○ genetic variation will increase because of a selective pressure.
○ genetic variation will increase because of a new habitat and food source.
○ genetic variation will decrease because of a selective pressure.
○ genetic variation will decrease because of a new habitat and food source.

Explanation:

1. Analyze the scenario: Snakes enter a new habitat with abundant food (rodents) and few predators.
2. Selective pressure and genetic variation: Selective pressure (e.g., competition for food, adaptation to new environment) can drive natural selection. When there's a new habitat and food source, and less predation, the snake population can expand, and traits that help survive in this new environment will be favored. This can lead to increased genetic variation as different alleles may be selected for, or new mutations may accumulate as the population grows.
3. Evaluate options:

• Option 1: "Genetic variation will increase because of a selective pressure." This is correct. The new habitat with abundant food and few predators creates selective pressures (e.g., competition for resources, adapting to new conditions) that can lead to natural selection, which increases genetic variation as favorable traits are selected and new mutations may arise.
• Option 2: The reasoning about "new habitat and food source" alone is not the direct cause of increased genetic variation; it's the selective pressures from the new environment that drive it. So this is incorrect.
• Option 3: Genetic variation is not likely to decrease here because there's no strong negative selective pressure (few predators, abundant food) that would eliminate alleles. So this is incorrect.
• Option 4: A new habitat with abundant resources is more likely to increase, not decrease, genetic variation as the population can thrive and evolve. So this is incorrect.

Answer:

A. Genetic variation will increase because of a selective pressure.