Ring species are examples of speciation in progress, where one species may turn into two. Evolution, in other words.
“Ring species are examples of speciation in progress, where one species may turn into two. Evolution, in other words.”
Please tell us what completely new, previously unknown, and more complex species arose in this manner. In order to be scientific evidence, this must be observable, reproducible, and predictive.
The crux of the latter is not precisely "speciation". The problem is the extrapolation that follows from that. Through apparent ring species, you have a salamander species which appears to be an ancestor and which seems to give rise to a different salamander species -- one with which the ancestor can no longer breed. OK. Interesting, but that doesn't take you as far as you want to go.
Look at whales instead. Once upon a time there was an animal that lived in the sea and had gills. That ancestor gave rise to a species which lived on land, lost its gills and developed lungs. That ancestor gave rise to a species that went back to the water, became absolutely huge, and gave rise to many other species. But no gills.
All of that took a long, long time, and lots and lots of intermediate species, right?
But this isn't really about species. It's about Kinds. Land animal? Sea animal? Gills? Lungs? No legs? Four legs? Fins?
Salamanders turning into salamanders is one thing. Fish turning into land-dwelling behemoths, or land-dwelling behemoths turning into Blue Whales is more than just a shade different.
And I don't think ring species is sufficient evidence for anyone to conclude "... and that's where whales come from."