Despeciation

Despeciation has been noted in species of butterflies, sunflowers, mosquitoes, fish, wolves, and even humans.

[2] Holarctic ravens and Californian ravens had been two separate species for 1.5 million years until tens of thousands of years ago when their regions overlapped and they began to merge into a new species.

[3] Another possible cause for despeciation is increased gene flow and hybridization due to changes in the environment.

They concluded that external factors had imperiled the living conditions of the two species, thus eliminating the evolutionary specializations that had kept them unique.

[5] Genes identified as being of Neanderthal and Denisovan origin have been located in the genome of modern humans in varying amounts dependent on location, and one Neanderthal-Denisovan hybrid nicknamed Denny has been identified, indicating that interbreeding took place where populations of the three species met.