Well, if there were no other evidence for evolution, I suppose we'd all have to go out and chase the "soup of life," (which seems to be the new "missing link," now that so many pre-human species have been found). But since there are literally mountains of evidence for evolution, I don't think there's all that much faith involved. Just reasoning.
I don't think "pre-human" ancestors have been established. Since man is the relative newcomer in the evolutionary cycle it would seem to me that the evolutionary trail would be the clearest and yet, there has been no clear evidence that man is the product of macro-evolution.