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Geneticist Claims Human Evolution Is Over
GogglesPisano writes "UK geneticist Steve Jones gave a presentation entitled Human Evolution Is Over. He asserts that human beings have stopped evolving because modern social customs have lowered the age at which human males have offspring, which results in fewer of the mutations necessary to drive evolutionary change. Apparently the fate of our species now depends upon older guys hooking up with younger woman. I, for one, welcome this development."
The author makes two additional points that the summary doesn't mention. Firstly, children born in the west are dramatically more likely to survive. They experience significantly less natural selection. Secondly, our large populations make any genetic fluke less likely to survive. Think of inbreeding here; with a small population, otherwise rare genes can become common. We're experiencing the reverse trend.
There's a blog post from PZ Myers on Pharyngula that addresses this statement from Steve Jones fairly well I think. Read it in full here
This[the idea that older men have more mutations in their sperm] is true, but it makes no sense. It's not as if younger fathers produce no mutations -- they generate plenty. It's a difference in degree, nothing more, so we still have plenty of new mutations percolating into the population. And of course, over most of human history parents have been relatively young, since you couldn't count on living to the age of 35.
And then there's this odd argument.
Another factor is the weakening of natural selection. "In ancient times half our children would have died by the age of 20. Now, in the Western world, 98 per cent of them are surviving to 21."
That makes even less sense. Natural selection is going to eliminate variants; by reducing its effects, we permit more mutations to persist in the population. One moment he's complaining that fewer mutations are being produced, the next he's complaining that the mutants are thriving. Which is it?
tl;dr = Steve Jones is full of wacky.
very true. If anyone disagrees, I suggest you watch the first five minutes of Idiocracy. In fact, you should watch the rest of the movie as well.
Human mind is not a clean slate. This has not been the consensus since the 60s.
The aptly titled book "The blank slate" by Steven Pinker is a really good overview of the research that has evolved our understanding of the nature and nurture debate.
There are genetic factors that influence intelligence, as well as environmental factors. The notion that everyone is born equal is unfortunately not true. (people are much more accepting that physical differences are genetic, but not mental...)
Control is an illusion, order our comforting lie. From chaos, through chaos, into chaos we fly
He's talking about the specific case where both parents are high intelligence. If it's recessive both must be II, so all the offspring will be.
It's similar to blue eyes (the simplified version, in practice it's a liitle more complicated).
Confucius say, "Find worm in apple - bad. Find half a worm - worse."
The biggest driver of evolution will always be catastrophic changes to the environment. Evolution advances rapidly when space in made available for mutations develop into empty spaces within the food chain in specific locals. It is very likely that the biggest driver for human evolution has been the relatively frequently recurring ice ages in recent geologic history.
Just as in future, the major drivers for human evolution will be those same ice ages recurring or, on own impact upon the environment being so great as to alter the environment sufficiently from the conditions under which we evolved as to force evolutionary adaptation to the new altered environment. Other changes in bacteria or viruses could also force associated changes in humans and, of course not to forget catastrophic impact.
Although evolution occurs across millions of years, there will be numerous periods, millennia, where evolution is accelerated fro particular species due to particular environmental conditions, so not much gradual change, but periods of relative stability interspersed with periods of accelerated change.
So as it has occurred in the past, a catastrophic event will either accelerate human evolution or end it, extinction being the only reason for a species to cease evolving. Crazy short haired rock throwing monkeys are really going to have to get over the idea that this universe needs or wants them to survive ;D.
Chaos - everything, everywhere, everywhen