My reasons for doubting are simple, yet incredibly hard to explain. Let me say this: look at modern dogs. They vary so much in size, shape, and other characteristics, yet they are all dogs and are produced not by Evolution (chance mutations with survival of the fittest) but by their built-in ability to reproduce. Yet, if you were to give me a plethora of modern dog bones (died within the last few years), I could eventually assemble them in such a way as to make one set of bones appear to be an evolved version of another set. And I could easy do such a thing by insinuating (and assuming) that any "gaps" in my little "evolutionary record" are simply fossils that haven't been found yet, or have been destroyed by whatever means.