The continued geographic isolation of Kaibab squirrels from Abert squirrels has allowed the animals to evolve into two distinct subspecies. This is an example of:

A) hybridization.
B) allopolyploidy.
C) adaptive radiation.
D) allopatric speciation.
E) sympatric speciation.

Allopatric Speciation

Speciation that occurs when one population becomes geographically separated from the rest of the species and subsequently evolves. Compare with sympatric speciation.

Geographic Isolation

A form of evolutionary separation where populations of the same species become physically divided by geographical barriers leading to genetic divergence.

Adaptive Radiation

The evolution of a large number of related species from an unspecialized ancestral organism.