House finches were found only in western North America until 1939, when a few individuals were released in New York City. These individuals established a breeding population and gradually expanded their range. The western population also expanded its range somewhat eastward, and the two populations have recently come in contact. If the two forms were unable to interbreed when their expanding ranges meet, what would this situation illustrate?

Question

Quizplus · Accepted Answer

This scenario fits the definition of allopatric speciation, which occurs when a population is separated geographically and over time evolves into a distinct species due to different selective pressures and genetic drift. The separation in this case was caused by the initial release of house finches on the East Coast, and the inability to interbreed upon their eventual range expansion indicates enough genetic divergence to warrant recognition as separate species. The other choices (sympatric speciation, vicariance, allopolyploidy, and autopolyploidy) do not accurately describe this scenario.

House Finches Were Found Only in Western North America Until