Time. Exactly. And I think this is one of the biggest problems with Creationists like the JWs. They have been taught that life as we know it was created in a relatively short window of time as part of a smooth, well planned (read: designed), purposeful process. Compare that notion to what science has discovered to be a multi-billion year process full of choas and drastic failures.
Through the narrow time period of 7,000 years of human history, as the JWs teach, it's hard to imagine both human evolution and large scale speciation. But expand the borders of time and it becomes more reasonable.
Personally, I feel the miracle is not that life was dreamed up and created by an organized Being but rather, that we are even here given the large rate of failure that preceeded us.