In biology, a ring species is a connected series of neighbouring populations, each of which interbreeds with closely sited related populations, but for which there exist at least two end populations in the series which are too distantly related to interbreed, though there is a potential gene flow between linked neighbouring populations.
Exactly. Ring Species are a good example
https://en.wikipedia.org/wiki/Ring_species
In biology, a ring species is a connected series of neighbouring populations, each of which interbreeds with closely sited related populations, but for which there exist at least two end populations in the series which are too distantly related to interbreed, though there is a potential gene flow between linked neighbouring populations.