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hart379 eNotes educator| Certified Educator
Speciation is caused by reproductive isolation. Speciation is the process of creating a new species. A species is a group of organisms that can mate and produce fertile offspring. Fertile offspring means that the offspring have the ability to reproduce. So, when two organisms can no longer mate to produce fertile offspring, they are no longer considered to be part of the same species. There are typically 3 ways in which organisms can become reproductively isolated. They are behavioral, temporal, and geographic. Behavioral isolation is when the organisms are in the same area but the mating rituals/behavior differ, so they chose not to mate. Temporal isolation is when the organisms are in the same area, but the time of day/year that they mate does not overlap, so they do not mate. Geographic isolation occurs when two organisms cannot come in physical contact with each other due to geographic barriers such as rivers or mountains. Speciation is a very slow process and takes a long time. The longer two organisms go without mating, the more likely it is that they will evolve adapt to their environments differently, and it is these different adaptations that will lead to different species.