The question is incomplete. Th ecomplete question is
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?
A) an increase in mutations in both bird populations
B) an increase in gene flow between the bird populations
C) an increase in genetic drift between the bird populations
D) an increase in mutations in the island population
Answer:
B) an increase in gene flow between the bird populations
Step-by-step explanation:
same species divided by geographic boundaries are unable to migrate due to distance but if both the species with able to migrate, then there will be increase in gene flow.
Gene flow is defined as transferring of genetic diversity among the population due to introduction of migrants. Migrants allows the chnages in genetic diversity by modifying the allele frequencies among the population.
Formation of sandbars and tiny islands will increase the chances of migration, as now either birds can take hold at tiny islands while moving to mainiland or small islands or both the population can migrate to tiny islands which directly results into increasing gene flow. Gene flow will further increases the diversity among bird populataion.
Hence, the correct answer is B.