Cambrian Explosion: mutation rate (Introduction)

by dhw, Sunday, September 15, 2013, 17:37 (4066 days ago) @ David Turell

DAVID: "They found that when some early branches of the arthropod family tree were splitting off, creatures were evolving new traits about four times faster than they did in the following 500 million years. The creatures' genetic codes were changing by about .117% every million years—approximately 5.5 times faster than modern estimates, the group reports online today in Current Biology. Lee calls this pace "fast, but not too fast" to reconcile with Darwin's theory."-Whistling in the wind. This does not account for the complexity of kidneys and livers and nervous systems. Fossil body forms are only a small part of the story.-http://news.sciencemag.org/evolution/2013/09/evolution%E2%80%99s-clock-ticked-faster-da...-QUOTE: The results not only show that the evolutionary clock ticked much faster around the time of the Cambrian, but also hint at what may have sped it up. The fact that genes and anatomy evolved at roughly the same rate suggest that pressures to adapt and survive in a world of new, complex predators drove both, the authors speculate. Innovations such as exoskeletons, vision, and jaws created new niches and evolution sped up to fill them. Wills agrees that the new research makes this explanation for the Cambrian explosion "look a lot more probable now."-I've read this a few times, and still don't understand it. Pressures to adapt and survive in a world of new, complex predators drove the evolution of genes and anatomy? I thought the new complex predators and prey, with exoskeletons, vision and jaws, and all the organs David has listed, were not the explanation but were the thing to be explained! -As for speed, how can anyone know what was feasible? We have nothing to compare it with. And so we speculate, just as we do about complexity. Random mutations? God having a field day dibbling and dabbling? Or how about a major change in the environment which enabled intelligent cell communities to experiment, creating organs that would not have been possible without such a change? Speed would then be irrelevant since there would have been so many potential inventors. There would certainly have been a mushrooming effect of inventions following on from or responding to earlier inventions (prey responding to predators and vice versa), but you still have to explain the initial burst of activity. For kidneys, livers and nervous systems to function, you require intelligent cooperation between cells and cell communities, regardless of whether God created the intelligence or not. Can anyone think of a more rational explanation?