"This week, we have a find in Arctic Canada that dates from the emergence of terrestrial vertebrates out of the seas about 375 million years ago. It's been known for a while that the lobe-finned fish were critical intermediaries in this process, but there were multiple changes involved in the transition, and the sequence in which they fell into place remained unclear. The new fossil, of a species named Tiktaalik roseae (Tiktaalik is the word for large, shallow water fish in the Inuktikuk language of Nunavut, where it was found) bridges that gap:

Although the body scales, fin rays, lower jaw and palate are comparable to those in more primitive sarcopterygians [the precursor fish], the new species also has a shortened skull roof, a modified ear region, a mobile neck, a functional wrist joint, and other features that presage tetrapod conditions.

In other words, most of the body was very fish-like, but the top of the head and neck were very much like those of the first amphibians. Meanwhile, much of the eventual terrestrial limb, including the shoulder, elbow, and parts of the wrist, were in place at the forelimb level, but not in the hind limb. Even the forelimb still ended in a fin, rather than digits, though. Although this beast was a predator, with a vaguely alligator-like head, the researchers suggest that it took advantage of its ability to drag itself onto land to escape predators. This is both because it would have moved too slowly to hunt down prey out of water, and it's unclear whether any prey was out of the water at the time. " (Ars Technica--4-06)

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If we keep on finding missing links at this rate we'll be back to square one. Or something like that.

Here's a question: does anyone know whether Big Bang theory asserts that space as well as matter began with the Big Bang? Or was space itself an existing initial condition of the Big Bang? Was the expansion generating apce as well as all matter? (Why does this feel like asking an adult hard questions about God?)

EIther way, I don't think we understand space very well; just as most fish do not know they are wet.


A