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 decrease because of a selective pressure. genetic variation will increase because of a new habitat and food source. genetic variation will decrease because of a new habitat and food source.

Explanation:

1. Analyze the situation: The snake population enters a new habitat with abundant rodent prey (many species, high populations, few predators).
2. Understand selective pressure and genetic variation: When a population has a new, abundant food source and suitable habitat, the selective pressure (environmental factors that influence survival/reproduction) changes. In this case, the snakes have more resources, so traits that were previously less favorable might now be viable, or new traits can be expressed. This leads to an increase in genetic variation because there's less strong selection against certain genotypes, and the population can expand and diversify genetically.
3. Evaluate the options:

• Option 1: "Genetic variation will increase because of a selective pressure." The new habitat with abundant food is a selective pressure (a change in environment that affects survival/reproduction). With more resources, the selective pressure is less harsh, allowing more genetic variation as different traits can be successful. This makes sense.
• Option 2: "Genetic variation will decrease because of a selective pressure." A decrease would happen if there was strong selection (e.g., only one type of rodent, and snakes with a specific trait survive). But here, there are many rodent species, so selection is not as strong, so variation should increase, not decrease.
• Option 3: "Genetic variation will increase because of a new habitat and food source." While the new habitat and food source are the cause, the mechanism is through selective pressure (the change in environment affecting survival/reproduction). The first option more accurately describes the biological mechanism (selective pressure) behind the increase.
• Option 4: "Genetic variation will decrease because of a new habitat and food source." As explained, with abundant resources, variation should increase, not decrease.

Answer:

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