Saturday, April 08, 2006

The DI's orwellian take on Tiktaalik

Young-Earth Creationists (YECs) have certainly been at this longer than the clowns over at the Discovery Institute. The DI has a remarkable statement on Tiktaalik that doesn't even require a rebuttal. They've just managed to do it themselves.
These fish are not neccesarily intermediates, explain Discovery Institute scientists I queried about the find. Tiktaalik roseae is one of a set of lobe-finned fishes that include very curious mosaics--these fishes have advanced fully formed characteristics of several different groups. They are not intermediates in the sense that have half-fish/half-tetrapod characteristics. Rather, they have a combination of tetrapod-like features and fish-like features. Paleontologists refer to such organisms as mosaics rather than intermediates.
I wonder if they could explain how an animal with tetrapod-like features and fish-like features is not an intermediate. This is followed by
What is clear is that forms like Tiktaalik are a melange of primitive and more developed features.
My word, this circus act just keeps getting better!
According to DI Fellows a number of these fishes—Ichthyostega, Elpistostege, Panderichthys—have been hailed in the past as the “missing link.” Maybe one is a missing link; maybe none are.
Once again, these guys have rather nicely pointed out their own ignorance and a few extra transitional forms, to boot! Nobody hails anything as "the missing link". "Missing link" is a term that scientists don't use and we even try to ask that the media does not use the term, but they do anyway. We can't stop them.

It was nice to see that they tossed in a mention of Elpistostege. As you can see, Elpistostege is a lot like Tiktaalik, which is why Tiktaalik is dubbed an "elpistostegalian". Elpistostege is known only very incomplete remains, the limbs have been entirely unknown. However, it's tetrapod affinities have been recognized since its discovery in 1938, when T.S. Westoll actually called it the earliest known tetrapod! In 1985, Hans-Peter Schultze and Marius Arsenault recognized it for what it was, a very tetrapod-like fish, similar to Panderichthys. In 1996, Schultze described a short pice of the trunk that has rhomboid-shaped schales and a few vertebrae. What little is known of its skull and trunk of Elpistostege is scarcely different from Tiktaalik. However, after decades of searching no new data on Elpistostege ever came to light. Shubin and Daeschler wanted more of this animal, but knew that the original locality wasn't going to give up its secrets. So, they went looking in similar-aged rocks elsewhere in the world. Their discovery of Tiktaalik essentially confirms the prediction of what we have long thought Elpistostege to be (and shows that Westoll was not too far off!)

Again, like AiG's response, the DI is simply responding to the media and not the original material itself.

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