Okay. Then I probably fall into the naysayer camp.

Given the presupposition of no "extraphysical" intervention, I agree that evolutionary theory is probably the best explanation for the current variety of life on earth. Though, even given that assumption I'm somewhat inclined to suspect intervention of the non-extraphysical variety (read: extra-terrestrial but not divine).

As an explanation for the sum total of current biological diversity, evolutionary theory strikes me as being pretty speculative. It's not the sort of thing one can reproduce in the lab.