Final answer:
The statement that genetic isolation can occur without reproductive isolation is False. Speciation, whether allopatric or sympatric, requires reproductive isolation, where allopatric involves physical barriers and sympatric relies on behavioral or genetic barriers.
Step-by-step explanation:
The statement genetic isolation can occur without reproductive isolation is False. Reproductive isolation is a necessary condition for speciation to occur, which includes both allopatric and sympatric speciation. In allopatric speciation, a geographic barrier leads to reproductive isolation, while in sympatric speciation, different behaviors or genetic variances such as polyploidy can create reproductive barriers, even within the same geographic region. Over time, due to different environmental pressures and genetic drift, the populations become genetically divergent enough to be considered separate species.
Allopatric speciation can happen through various mechanisms such as a river forming a new branch, or seeds dispersing to a new island. In contrast, sympatric speciation can take place when there are no geographic barriers, but instead, reproductive isolation occurs through other means such as chromosomal errors or differing behaviors that reduce gene flow between parts of a population in the same area. Examples of sympatric speciation suggest that even when populations are not physically separated, they can still evolve distinct genetic identities due to reproductive isolation mechanisms such as polyploidy in plants or divergent selection pressures influencing traits like mating behavior or diet.