•Speciation in Ensatina salamanders has primarily occurred through allopatric ring speciation , where a single ancestral population in northern California split and moved south on either side of the Central Valley of California, a large dry region unsuitable for salamanders.As populations spread around both sides of the central valley - one branch along the coastal mountains and the other along the Sierra Nevada mountains, becoming geographically isolated, no single population could cross the dry valley.
Each branch adapted to its local environment. This led to gradual genetic divergence. the morphological and genetic differences increased over time leading to Gradual Divergence into Subspecies.
