In “Sorry, Ring Species Do Not Provide Good Evidence for the Origin of New Species by the Darwinian Mechanism” (Evolution News & Views, April 6, 2012), Casey Luskin notes,
Ring species are chains of geographically adjacent populations, in which each population interbreeds freely within itself but somewhat less freely with those adjacent to it, and the populations at the ends of the chain do not interbreed when they come in contact. By the most common definition of “species,” the populations at the ends of the chain have become separate species.
Great idea, now let’s see it demonstrated:
The classic example of a ring species was the herring gull, with populations circling the northern hemisphere. But this example is not what it has been advertised to be. In a 2004 paper titled “The herring gull complex is not a ring species,” German and Dutch biologists concluded:
What earlier authors… regarded as “the herring gull” turned out to be an assemblage of several distinct taxa (argentatus, vegae, smithsonianus), which are not each other’s closest relatives. Our results show that the ring-species model does not adequately describe the evolution of the herring gull group.
Another often cited example was the Ensatina salamander.
And guess what? More.
Darwinist philosopher Daniel Dennett likes to say that Darwin had “The Single Greatest Idea Anyone Ever Had”
And if a great idea is all you want, be a Darwinist. If factual biology is what you want, don’t go there.