11. The two species are allopatric across the Sanaga River. 12. The five species are entirely allopatric , their distributions being separated by major rivers. 13. This may arise from human alteration of habitats enabling related allopatric species to overlap. 14. Reproductive isolation can be caused by allopatric speciation. 15. The two species are entirely allopatric ( their distributions separated by major rivers ). 16. Its small size is a result of island dwarfing, a kind of allopatric speciation. 17. The four species are almost entirely allopatric . 18. An allopatric medical degree is not required. 19. Speciation can occur sympatric speciation or allopatric speciation ( and a few other ways ). 20. Many allopatric forms previously regarded as conspecific are treated by Rasmussen and Anderton as full species.
