While we're on the topic of the Tiktaalik transitional form fossil, I'd like to mention a post by Ed Brayton at Dispatches from the Culture Wars that addresses more foolish Creationist comments, these by Casey Luskin, one of the fellahs at the Discomfiture Institute. Luskin's argument is absurd, misrepresents the science, and is self-contradictory. Ed critiques the commentary and notes the important distinction between the Bozos at the DI and real scientists:
But you see, this is where we come to a key difference between how actual scientists deal with the data and how ID advocates deal with the data: actual scientists will now continue to look for the evidence that fills in the details. And when they find another specimen that allows us to verify those details with greater specificity than we can now, the ID crowd will react to that one the same way they reacted to this one, by pretending that since we didn't have answers for every single specific question of how the transition took place before that point, we couldn't possibly have been able to understand that any transition took place at all.Just ahead of this Ed mentions a couple examples of scientists using their understanding of evolution to describe some aspects of the fossil record that they predicted would be found:
What Luskin conveniently ignores is that the existence of this intermediate form was predicted by scientists based upon the evidence we already had showing the early and later stages of the transition. That prediction was, in essence, a test of the theory that amphibians evolved from lobe-finned fish. If that theory is true, given the fossil evidence we already had, then there should exist at least one species and probably more than one that showed a morphology intermediate between Panderichthys and the true tetrapods. Furthermore, it had to exist in rocks of a certain age (370 million years, give or take) and in a certain environment (shallow marine, particularly rivers). So they began to search where they predicted such a species would be found and, lo and behold, they found one.
And incidentally, the same thing happened in documenting the transition from land mammals to whales. Predictions were made on the nature, age and circumstances in which that transition took place - again, based on the evidence from the beginning and later stages of the transition that we already had - that narrowed it down to a specific type of sediments (shallow marine) in a specific geographic location (Pakistan and India) and of a specific age (50 million years old). And once again, the prediction was borne out. Both predictions are brilliantly documented in Carl Zimmer's book At the Water's Edge.
And some people would have us think that twits like Casey Luskin are modern day Galileos?