If the original finches that had been blown over to the Galápagos from South America had already been genetically different from the parental population of South American finches, even before adapting to the Galápagos, this would have been an example of

A) genetic drift.

B) bottleneck effect.

C) founder effect.

D) all three of these.

E) both the first and third of these.

If the original finches that had been blown over to the Galápagos from South America had already been genetically different from the parental population of South American finches, even before adapting to the Galápagos, this would have been an example of

E) both the first and third of these.

Explanation:

Genetic drift was the process of changing of allele frequencies over generations in a random fashion.

Founder effect is closely linked with the genetic drift. In this case, a few individuals of the original population start a new colony isolated from the other members of the species.

A founder effect happens when a new colony started from few members of the original population. The small size of population means that the colony may have a small variation of the genes in the original population.

A founder effect event happens when a small group of individuals was separated from the rest of the population, whereas a bottleneck effect occurs when most of the population is destroyed.