I didn’t review my last post and thus it wasn’t clear. Sorry. The definition of a species is animals or plants that can mate and have fully functioning offspring. When successful mating is no longer possible, you have different species. A horse and a donkey can mate but the offspring is most often unable to reproduce — a mule. Thus, although they appear similar and doubtless have common ancestor, horses and donkeys are separate species.
The missing element for understanding change is time. Most animals have very short lifetimes and they reproduce often. That’s a lot of opportunity for mutations and some drift. When you consider genetic drift and mutation over thousands and even millions of years, you can grasp evolution. Sometime back in time every animal and every plant has a common ancestor. Look up a modern (ie 2014 ) representation of the tree of life and you’ll see what I mean.
So we have come full circle with the NEED for time in-order to MAKE the TOE work.
When successful mating is no longer possible, you have different species./i>
No. When successful mating is no longer possible you actually have extinction.
Darwin made a big deal out of dog breeding. Nevermind they are still dogs. To get a "Chocolate Lab" breeders breed yellow labs with black labs. You can't get a chocolate lab by breeding two chocolate labs no matter how many times you try.