Refer to the map below. DNA analysis showed that one species of rat diverged over several thousand years to become two species.Rat species A lived in the Ethiopian biogeographic region, whereas species B lived in the Oriental region.This suggests that the process leading to divergence of the two rat species is
A) dispersal.
B) vicariance.
C) biogeography.
D) converging of land masses.
E) biotic interchange.

Question

Refer to the map below.  DNA analysis showed that one species of rat diverged over several thousand years to become two species.Rat species A lived in the Ethiopian biogeographic region, whereas species B lived in the Oriental region.This suggests that the process leading to divergence of the two rat species is
A) dispersal. 
B) vicariance. 
C) biogeography. 
D) converging of land masses. 
E) biotic interchange.

Quizplus · Accepted Answer

The fact that two rat species diverged over several thousand years in different biogeographic regions suggests that the process leading to their divergence is vicariance, which occurs when a formerly continuous geographic area becomes divided into separate parts by a geographic barrier, such as a mountain range, river or oceanic trench. In this case, the geographic barrier that facilitated the divergence of the two rat species was likely the separation of the Ethiopian and Oriental regions. Dispersal, biogeography, converging of land masses, and biotic interchange are not relevant explanations in this context.

Refer to the Map Below