Imagine a very deep lake with multiple species of fish. The lake has many different regions (i.e., shallow water with high light penetrance, deep water with low light penetrance). A phylogeny of the fish shows that they have all descended from a common ancestor. Which of the following is the MOST likely cause of speciation in fishes in this lake?
A)allopatric speciation
B)peripatric speciation
C)sympatric speciation

Question

Quizplus · Accepted Answer

The fact that the lake has multiple regions means that there are potentially varying ecological niches and selection pressures. This, combined with the phylogenetic evidence of a common ancestor, suggests that speciation likely occurred through sympatric mechanisms, where new species evolved in the same geographic area due to ecological divergence or other factors such as mate selection. Allopatric speciation, where populations are geographically separated, and peripatric speciation, where a few individuals from a larger population colonize a new area, are less likely scenarios in this context.

Imagine a Very Deep Lake with Multiple Species of Fish