Allopatric Allopatric speciation occurs when the new species evolves in speciation geographic isolation from the parent species. It may take place most readily in peripheral isolates, small populations at the extreme edge of a species range. The combined effect of a small atypical population and extreme environmnental conditions can cause rapid and extensive genetic reorganization(a genetic revolution) leading to speciation This form of speciation occurs where the speciating Parapatric populations are contiguous but subject to different speciation environmental(e.g. climatic) conditions in different parts of the range, Intermediate hy brids are found, as in ring species but the large distances involved prevent the two types from merging completelyAllopatric speciation occurs when the new species evolves in geographic isolation from the parent species. It may take place most readily in peripheral isolates, small populations at the extreme edge of a species range. The combined effect of a small atypical population and extreme environmnental conditions can cause rapid and extensive genetic reorganization (a genetic revolution) leading to speciation. Allopatric speciation This form of speciation occurs where the speciating populations are contiguous but subject to different environmental (e.g. climatic) conditions in different parts of the range, Intermediate hybrids are found, as in ring species, but the large distances involved prevent the two types from merging completely. Parapatric speciation