Seriously -- if x-great-grandchildren can produce viable offspring, why does that not suggest "same-species" to you?
OTOH, I do see your larger point, which is that eventually the two breeding lines should become different species, such that x-great-grandchildren don't produce viable offspring.
This is not in the least "undoubted".
I was referring specifically to the possibility of mating a modern-day teacup poodles, and the crossbreed great-grandchild of a great dane. I hold that that is indeed "undoubted."
As for your other examples, I'm not going to address them, except to point out that those near-relative species do in fact exist, and can mate to produce live, if not fertile, offspring. Obviously they got that way somehow. Beyond that I will say no more, except to point you to my previous comments on this thread.
Why, it does...provided you can actually show me a case where the divergence lasts for, say, 1,000,000 years, so that the teapot dog becauses about the size of the Great Dane's spermatazoa and then converges again when they are respecively upsized and downsized. Darwin and the DNA mutational clock sez--not a snowball's chance in hell. Creationists say, "of course". Neither side is putting up a slamdunk demonstration, but Darwinists do have those three annoying trees of evidence, from the geological column, the DNA clock and the continuity of fossil morphology, and a thriving micro-biology insdustry to point to, whereas creationists can proudly point to God-did-it, with, of course, no possiblility of any trail of evidence to follow backwards from that event.
As for your other examples, I'm not going to address them
I wouldn't want to either, if I were you.
, except to point out that those near-relative species do in fact exist, and can mate to produce live, if not fertile, offspring. Obviously they got that way somehow. Beyond that I will say no more, except to point you to my previous comments on this thread.
Yea, they got there somehow--byh the gradual divergence of functionally, or geographically isolated hybrids, as suggested should be the case by Darwin's theory.