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.

Answer 1

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

Reason: the hurricane caused a population bottleneck. In small (island) populations random changes in allele frequencies (genetic drift) can rapidly reduce genetic variation; larger mainland populations are buffered against drift and retain (or more easily recover) genetic diversity.