Which type of reproductive isolation occurs due to physical barriers?

Geographic isolation is a type of reproductive isolation that happens when physical barriers, such as mountains, rivers, or distance, separate populations of a species. This separation prevents individuals from mating with one another, even if they are capable of reproducing under normal circumstances. Over time, the separated populations may evolve independently, leading to the development of distinct species.

In the context of reproductive isolation mechanisms, geographic isolation is fundamental because it establishes a physical separation that can trigger evolutionary changes, as the separated groups adapt to their respective environments. The other types of isolation—temporal, behavioral, and gametic—are centered around timing, mating behaviors, and reproductive compatibility, rather than physical barriers that prevent individuals from coming into contact with one another. This distinction underscores the importance of geographic isolation as a catalyst for speciation.