Your textbook authors make the claim that "sympatric species with matching chromosome numbers are rare." Why is this?
A) because allopatric speciation is far more common
B) because sympatric speciation has only been hypothesized but not documented
C) because coexisting populations need a boundary to gene flow before divergence can occur, and differences in chromosome numbers provide this
D) because macroevolution is just a theory

Question

Quizplus · Accepted Answer

Sympatric speciation involves the divergence of populations that coexist in the same geographic area. To achieve this, some type of reproductive isolation must evolve. Coexisting populations need a boundary to gene flow before divergence can occur, and differences in chromosome numbers provide this boundary. Therefore, sympatric species with matching chromosome numbers are rare.

Your Textbook Authors Make the Claim That "Sympatric Species with Matching