Question

henry was studying two populations of the same species of lizards. one population lived on an island and the other lived on the mainland. both populations were affected by a hurricane that hit the island and the mainland with equal force. a year later, henry was testing the gene frequency and saw a decrease in genetic variation in the island species, but not in the mainland species. which best describes a conclusion he might have reached?
○ gene flow greatly affects small populations, but large populations can recover.
○ genetic drift greatly affects small populations, but large populations can recover.
○ gene flow greatly affects large populations, but small populations can recover.
○ genetic drift greatly affects large populations, but small populations can recover.

Explanation:

Island lizard populations are typically smaller than mainland ones. Genetic drift is the random change in gene frequencies, which has a much larger impact on small populations (as random events can more easily reduce genetic variation). The hurricane acted as a random event that caused genetic drift, reducing variation in the small island population, while the larger mainland population was minimally affected and maintained its genetic variation. Gene flow involves transfer of genes between populations, which is not the factor at play here.

Answer:

Genetic drift greatly affects small populations, but large populations can recover.