From Quanta Magazine:
Researchers build the world’s largest evolutionary tree and conclude that species arise because of chance mutations — not natural selection.
What? They are allowed to say that now?
One reason scientists are skeptical is that Hedges’ clocklike pattern conflicts with the traditional picture of how evolution unfolds. “The classic view of evolution is that it happens in fits and starts,” Benton said. A change in the environment, such as a rise in temperatures after an ice age, might spark a burst of speciation as organisms adapt to their new surroundings. Alternatively, a single remarkable adaptation such as flight in the ancestors of birds or hair in mammals might trigger a massive expansion of animals with those characteristics.
Hedges argues that while such bursts do occur, the vast majority of speciation is more prosaic and evenly timed. To start, two populations become separated, driven apart by geography or other factors. New species emerge every 2 million years, on average, in a metronomic rhythm tapped out by the random nature of genetic mutations. He likens the process to radioactive decay. It’s impossible to predict when an individual radioactive nucleus will decay, but a clump of many atoms will decay at a highly predictable rate known as the material’s half-life. Similarly, mutations strike the genome randomly, but over a long enough time the accumulation of mutations follows a pattern. “There is a kind of speciation clock ticking along,” Hedges said.
Hedges maintains that constant speciation times are driven by the relatively constant pace of genetic mutations across the natural world. But it’s possible that Hedges’ consistent speciation rates result from averaging different rates across a range of organisms, Benton said. “To suggest a kind of regular pattern is one people will find quite challenging,” he said. “I see where they get it from, but I think there are other possible explanations.”
While researchers debate their findings, Hedges’ group is already working on an even bigger tree — one with perhaps half a million of the roughly 1.5 million known species. “That will give us a more accurate picture of the evolution of life and how biodiversity will change in the future from human activities,” Hedges said.More.
There is a lot of doubt, criticism, and skepticism about this, but the striking thing is that it can even be discussed.
Which means … if you do not have a job fronting Darwinian evolution (natural selection acting on random mutation)—and assuming that it is not, for all practical purposes, your religion—as is clearly the case with many of our commenters—would you invest in it today? Why?
Steve Pinker, stomp out of the Science Festival too, following Dan Dennett, will you? Thing is, no one cares any more. The world is moving on.
See also: What’s this about the strange inevitability of evolution? So this is a demonstration of the fine tuning of the universe for life? But isn’t that heresy?
Is the Tree of Life just an art exhibition now?
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