Wow, in the last 4,000 years, lions and tigers have diverged from a common ancestor, and possibly all the cats descend from a single "kind" that Noah took aboard the ark. I guess all the bears were represented by a single "bear kind" on the ark as well!
What that means is that creationists believe in not just evolution, but a souped-up hyper-evolution on steroids. If you believe that tigers and lions diverged into their present states in just 4,000 years, you should have no trouble at all in accepting that all vertebrates diverged from a common ancestor in the last few hundred million years. In fact, at the rate they apparently believe, creationists should expect that all the vertebrates could evolve in less than a million years.
Check in to Dog breeding sometime. You would be amazed at what they have done with breeds in just a few years. Not 4000 years!