Question

A small population of a species of bird is blown by a storm from the mainland to an island offshore, which is outside of its normal flight range. This island population subsequently diverges for a very large number of generations after which it can no longer interbreed with individuals from the mainland population when given the opportunity. What process is described in this scenario?

a) Genetic drift
b) Allopatric speciation
c) Convergent evolution
d) Natural selection

Answer 1

Allopatric speciation is the process where a bird population becomes geographically isolated on an island and evolves so significantly over generations that it can no longer interbreed with the mainland population.

Step-by-step explanation:

The process described in the scenario where a bird population is isolated on an island and then diverges so much that they can no longer interbreed with the mainland population is known as allopatric speciation.

This isolation can be caused by dispersal, which occurs when a few members of a species move to a new geographical area, or vicariance, when a natural situation physically divides organisms.

The geographic isolation is key to allopatric speciation, preventing gene flow between the separated populations, ultimately leading to speciation as natural selection, mutation, and genetic drift cause the populations to diverge genetically over many generations. This emphasizes the importance of geographic isolation in the speciation process.