Final answer:
Genetic isolation does not require a geographic barrier because, in addition to allopatric speciation, there is also sympatric speciation that occurs without geographic barriers through behavioral or ecological separation.
Step-by-step explanation:
The statement that genetic isolation requires a geographic barrier is False. While allopatric speciation involves geographic isolation leading to speciation, there is also sympatric speciation, which occurs without such barriers. Reproductive isolation is essential for speciation, and this can occur through either prezygotic or postzygotic barriers, which prevent gene flow between populations. Allopatric speciation may happen due to various geographic changes, such as river formation, erosion, or long-distance dispersal of seeds. However, with sympatric speciation, divergence may occur in the same geographic location if there are behavioral or ecological niches that lead to reproductive separation within a population.