Ecotypic variation

In population genetics, ecotypic variation is the type of genetic variation found in a large continuous geographic populations. Variation of this kind is , due to factors such as gene flow. In 1954 Ernst Mayr wrote a landmark paper attacking the idea that subspecies in ecotypic populations lead to formation of incipient species. According to Mayr species formation occurred in populations which were small and isolated, that is, populations which exemplified typostrophic variation.

...
Wikipedia