Dancing with Tiktaalik – a fishy comment breaks bloggers’s block
Some of you may have noticed that I haven’t been posting recently. It’s been three weeks, and in between wallowing in guilt for my lack of literary (?) output (wallowing in guilt is a particular hereditary skill of mine, passed down through untold generations of eastern European Jews who constantly worried that some personal vice of theirs was responsible for the latest bad turnip harvest) I have been searching diligently – more or less – for something compelling to write about. My problem has been neither lack of will nor broken fingers; there simply hasn’t been much going on that seemed worth the effort.
Two days after my last post, scientists announced the discovery and description of Tiktaalik roseae, a 375-million-year-old fish that fit nicely into one of the gaps in the fossil record of the transition from purely aquatic to terrestrial vertebrates. (See also here and here.) The “new” fossil was “discovered to order” – that is, it was found in a predicted location (an area of Greenland that was once a subtropical region of meandering streams) and at the predicted time (that is, in rocks of the right age) for a creature of approximately these characteristics to exist. From the standpoint of evolutionary science, such a find is obviously most welcome, and yet it is anything but revolutionary: Tiktaalik answers some questions about the details of the fish-to-amphibian transition, but it doesn’t create any new paradigms or overturn any old ones.
Nonetheless, anti-evolutionists of various cuts and stripes felt compelled to react to Tiktaalik – here’s an analysis of some conventional creationist critiques of the new fish, and here is an Intelligent-Design-style critique from the Discovery Institute’s Center for Science and Culture (analyzed here).
None of this would have triggered a blog post, since evolutionary biology is supposed to be merely a side-line for me, and the new fossil – and responses to it – don’t change anything in my thinking on the subject.
However – and remember the part about my having difficulty finding anything to write about? – today I came across one comment in that last link’s discussion thread that was so wonderful that it got my rusty fingers pounding the keys again. (I really do pound the keys; Vaguely Sinister Wife complains if I do any writing while she’s trying to get to sleep. We didn’t have none of these newfangled electronic gizmoes when I learned to type – it was good old-fashioned cast-iron manual typewriters, and don’t your forget it, sonny! But, as usual, I digress.) The pseudonymous genius (and I’m not being sarcastic!) quotes a passage from the original commentary, referring to the nature of the evolutionary changes represented by Tiktaalik:
But that kind of mosaicism is what you'd expect, and what we should see in a transitional form! Every element of the organism shouldn't be changing in a slow and steady lockstep, but instead should shift haltingly, with sometimes most of the selection on the feeding structures, for instance, and maybe some other time on locomotor morphology.
Why do you hate Jesus?
…Which has to be the best capsule-summary-cum-demolition of the creationist “argument” I’ve ever read.
Sigh… I wish I’d written that!