Which geographical barrier is an example leading to allopatric speciation?

Geographical barriers are significant factors in allopatric speciation, which occurs when populations of a species become physically separated, leading to the development of distinct species due to evolutionary processes. Mountain ranges serve as classic examples of such barriers because they can physically divide populations, preventing gene flow between them.

When a population is split by a mountain range, individuals on either side may adapt to distinct environmental conditions, facing different selective pressures. Over time, genetic divergence can occur as mutations accumulate, and natural selection favors different traits in each population. This separation and resulting evolutionary path can lead to the formation of new species.

While urbanization can modify habitats and create fragmented environments, it doesn't necessarily lead to clear-cut separation like mountain ranges do. Climate change can impact species distribution and gene flow but is not a physical barrier in the same sense. Migration involves the movement of individuals within a species, often promoting gene flow rather than acting as a barrier that leads to speciation.