I guess it depends on whos definition of teleology you are working with. Teleolgy, to Aquinas, was just the fact that physical things have certain dispositions: ice melts when it gets too warm, wood burns, quantum particles don't decay into flowers but into other particles, etc. It seems to me this sort of teleolgy is self-evident, and you would have to reject nearly every piece of scientific literature out there, which seems like a harsh conclusion and unwarrented skepticism. If you are working with Paley's defintion, the one which is often employed, then I have a bit less to say. In my opinion, the intelligent design folks might (might is an important word. I wouldn't defend their positions too strongly) have something going for them when it comes to the existence of the first single celled organism. It seems pretty unlikely on a purely naturalistic worldview that such a thing would arise. The best evidence of teleolgy in nature, in my opinion, would be the fine tuning argument; however, a multiverse hypothesis seems to me more probable than a theistic one. If you really want to know more about this, I would ask Atno. Personally, I think teleological arguments, although interesting, don't get very far.