A Storm Blows a Small Group of Migrating Birds Off

Multiple Choice

A storm blows a small group of migrating birds off course and they land on an island,where they remain for 100 generations.At this time,a second storm brings more birds from the mainland population to the island.These new birds cannot mate with the established birds,even though they are originally from the same population.What mechanisms are likely to have been involved in bringing about this speciation? Select all that apply.

A) Genetic drift
B) Polyploidy in the mainland bird population.
C) Founder effect
D) Adaptation to a new ecological niche