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Humans Evolving Faster?

Posted: Wed Jan 09, 2008 1:25 pm
by Beagle ... 120607.php
Researchers discovered genetic evidence that human evolution is speeding up – and has not halted or proceeded at a constant rate, as had been thought – indicating that humans on different continents are becoming increasingly different.

“We used a new genomic technology to show that humans are evolving rapidly, and that the pace of change has accelerated a lot in the last 40,000 years, especially since the end of the Ice Age roughly 10,000 years ago,” says research team leader Henry Harpending, a distinguished professor of anthropology at the University of Utah.

Harpending says there are provocative implications from the study, published online Monday, Dec. 10 in the journal Proceedings of the National Academy of Sciences:

-- “We aren’t the same as people even 1,000 or 2,000 years ago,” he says, which may explain, for example, part of the difference between Viking invaders and their peaceful Swedish descendants. “The dogma has been these are cultural fluctuations, but almost any temperament trait you look at is under strong genetic influence.”

-- “Human races are evolving away from each other,” Harpending says. “Genes are evolving fast in Europe, Asia and Africa, but almost all of these are unique to their continent of origin. We are getting less alike, not merging into a single, mixed humanity.” He says that is happening because humans dispersed from Africa to other regions 40,000 years ago, “and there has not been much flow of genes between the regions since then.”

“Our study denies the widely held assumption or belief that modern humans [those who widely adopted advanced tools and art] appeared 40,000 years ago, have not changed since and that we are all pretty much the same. We show that humans are changing relatively rapidly on a scale of centuries to millennia, and that these changes are different in different continental groups.”

The increase in human population from millions to billions in the last 10,000 years accelerated the rate of evolution because “we were in new environments to which we needed to adapt,” Harpending adds. “And with a larger population, more mutations occurred.”

Posted: Wed Jan 09, 2008 3:10 pm
by Digit
There is in that post Beag an implication of our being a hybrid.
Most species will remain 'fixed' for ever unless external forces are applied.
Cross breeds seem to repeatedly shuffle their genes till a stable format is obtained.

Posted: Wed Jan 09, 2008 3:28 pm
by Minimalist
I find myself evolving huge butt muscles to enable my sitting at this goddamn computer all day long.

Posted: Wed Jan 09, 2008 3:44 pm
by Digit
Know the problem, I'm switching between two forums and it's been a busy night, and enjoyable.

Posted: Fri Jan 11, 2008 9:21 am
by Digit
There is in that post Beag an implication of our being a hybrid.
Agreed everyone?

Posted: Fri Jan 11, 2008 9:27 am
by Beagle
humans dispersed from Africa to other regions 40,000 years ago, “and there has not been much flow of genes between the regions since then.”
Maybe a little bit there Dig. But Hawks believes the proof may be found soon. He isn't very subtle about it.

Posted: Fri Jan 11, 2008 9:44 am
by Digit
My reasoning is this Beag.
The Polar Bear and it's NA cousins can interbreed, therefore they must have had a common ancestor.
If natural selection is to work at all then both forms will continue to refine their adaptions to their environments, I see no reason to assume that evolution will halt within their separate species.
The logical outcome would then be that eventually they would no longer be able to interbreed. Also their dependence on their specific environments would make them less adaptable to changes in their environent.
Darwin believed that natural selection worked to fix speciation unless a change in environment occurred, which seems logical, it it ain't broke. don't fix it!
If natural selection is to work at all on hybrids then continous shuffling of genes must work to make that hybrid better suited to its environment, and hybrids must have a better chance of re-shuffling their genes than species that has bred true for many generations.
The ultimate 'goal' of natural selection must be to make a species less and less able to survive changes, Koala Bears, Giant Pandas, host specific parasites, all seem to be the end game.

Posted: Fri Jan 11, 2008 9:59 am
by Beagle
I agree with that Dig. I think Polar bears and Brown bears are excellent examples of the situation between. Neandertal and HS. (Notice that I'm saying HS - not HSS).

I think I read that seals were once a member of the bear family. They obviously are too genetically separated to breed. So time makes a difference. Small mutations also occur naturally, but most are not adaptive. Those few that are spread through the population rather quickly, or used to. With such a large world population, human types on different continents are interbreeding less frequently than ever before. Per capita, that is.

Posted: Fri Jan 11, 2008 10:04 am
by Digit
And it would seem that, in an ever changing world, all species must ultimately face extinction Beag.
We may be the first species to bring it upon ourselves, or altenatively be the first species to avoid that fate.

Posted: Fri Jan 11, 2008 10:09 am
by Beagle

One of your physicists, Hawkings, has said that survival of the human race ultimately depends on our colonizing other planets.

I must go for a short while. Back later. :D