Speciation

Speciation is the evolutionary process by which new distinct species arise in evolutionary systems. A species is a reproductively isolated, independent evolutionary unit which occupies a certain niche. In the course of evolution, a lineage of a species can split into two or more. The branching points in the phylogenetic tree mark the speciation events, where a new species emerges. A main reason for speciation in biology is geographical and reproductive isolation.

The major cause of speciation in biological systems is geographical separation or isolation, the four major types of speciation in nature are based on the extent to which speciating populations are geographically isolated from one another: allopatric, peripatric, parapatric, and sympatric.