The occurrence of population of related organisms in separate, non-overlapping geographic areas such that members fail to encounter one another, hence, are unable to crossbreed.
Allopatry leads to genetic isolation due to geographic separation, and results in the formation of new species over time.
Word origin: ancient Greek allos, other+ Greek patrā, fatherland.
Related forms: allopatry
See also: allopatric speciation, Genetic isolation.