There are several types of speciation:
1. Allopatric speciation occurs when populations are physically isolated by a barrier and evolve reproductive isolation.
2. Sympatric speciation happens when two groups of the same species live in the same area but evolve differently until they can no longer interbreed.
3. Parapatric speciation occurs when a smaller population is isolated at the periphery of a larger group and becomes differentiated to the point of becoming a new species, with possible continued gene flow.