Question

a population of birds lives on a small island. another population of the same species lives on the mainland. the distance between the island and the mainland is too great for birds to fly back and forth. recently, a series of sandbars and tiny islands have formed between the island and the mainland.

what is the most likely effect of this?

an increase in mutations in both bird populations

an increase in gene flow between the bird populations

an increase in genetic drift between the bird populations

an increase in mutations in the island population

Explanation:

1. Analyze each option:

• Mutations are random and not directly caused by the formation of sandbars/tiny islands, so options about increased mutations (first and fifth) are incorrect.
• Genetic drift is random change in allele frequencies, not related to the new landform facilitating movement.
• Gene flow is the transfer of genetic material between populations. The sandbars/tiny islands provide a path for birds to move between the island and mainland, so gene flow (second option) would increase as birds can now migrate (or move) between the two populations, exchanging genes.

Answer:

B. an increase in gene flow between the bird populations