With Nautilus and Neil Shubin:
Shubin and his team learned from Tiktaalik fossils that the big fish with the flat head had a shoulder, elbow, and wrist composed of the same bones in a human’s upper arm, forearm, and wrist. Tiktaalik used those bones to navigate shallow streams and ponds “and even to flop around on the mudflats along the banks.” Here was the creature from the lagoon that revealed how animals evolved from fish to us.
Interesting presentation.
But Tiktaalik wasn’t the first land-dwelling tetrapod. Trackways have been found from 20 million years earlier:
Tetrapod paleontologist Jenny Clack said their discovery “blows the whole story out of the water, so to speak.” It is perhaps of interest that some fish, even today, routinely spend time out of the water, using primitive lung apparatus and walking on fins, but there is no particular reason to believe that they are on their way to becoming full time tetrapods or land dwellers.
Evolution should mean ancestry, and ancestry doesn’t just mean having body parts analogous to earlier ones. It should mean that we are direct descendants, not just that we make use of the same general idea.
Tiktaalik may well have died out leaving no descendants. We could be descendants of an as-yet-unfound creature that used these body parts quite differently from Tiktaalik.
Such distinctions are likely lost of people who believe vaguely in “evolution” and like to hear inspiring talks about it.
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Tiktaalik (Attenborough team’s rendering):