Speciation is the process in which a new species is formed from an initial one.

In the abstract, the following events must happen in the origin of a new species:

1. There is a single species, made up of a set of interbreeding organisms.

2. A genetic variant must spread through part of the species and the bearers of this variant must mate only with other bearers of the same variant.

3. The species will have now split into two: from one initial population, two separate interbreeding populations will have evolved. Along the way, further phenetic, behavioral and ecological differences may also evolve.

The process of speciation is described by the biologist David Haig.