Oh, man, Casey Luskin is such an embarrassing spokesperson for the intelligent design creationists — I hope they keep him employed forever. His latest tirade against me is a cacophany of inanity. His primary point is that creationists like Jonathan MacLatchie have forced me to make concessions to creationism when I say that there are differences between vertebrate embryos. It is no concession to anything other than reality: the differences have been known for a long time. My first laboratory experiences as a graduate student were doing work on frog embryos with Phil Grant at the University of Oregon; my second were working with zebrafish embryos with Chuck Kimmel. Guess what: I could tell them apart, easily, as a first year grad student. I can also tell the difference between a zebrafish and medaka embryo! So this is a stupid claim on his part.
Here’s his second major absurdity:
If PZ is correct that evolutionary biology predicts both similarities and differences among embryos, then evolutionary biology makes no predictions and is unfalsifiable regarding the similarities and differences in vertebrate development. According to PZ, evolutionary theory predicts whatever it predicts, conserves whatever it conserves, and modifies whatever it modifies. Some theory.
Look at a cat and a dog. They are different animals; they have different forms and behaviors. However, they also have deep similarities: they are mammalian carnivores, they have the same basic bone structure, they have very similar physiologies. Any theory that purports to explain the existence of these two organisms must account for both the similarities and differences. Evolution would be falsified if it predicted that every organism was exactly the same, or if it predicted that every organism was completely different, because that isn’t what the real world looks like.
Go back to third grade, Casey. You are a very silly, ignorant fellow.