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Dr. Bob is Robert Hsiung, MD,
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Posted by Nickengland on September 9, 2005, at 18:54:25
'Proof' our brains are evolving
The changes presumably confer a survival benefit
University scientists say they have found strong proof that the human brain is still evolving.
By comparing modern man with our ancestors of 37,000 years ago, the Chicago team discovered big changes in two genes linked to brain size.One of the new variants emerged only 5,800 years ago yet is present in 30% of today's humans, they believe.
This is very short in evolutionary terms, suggesting intense selection pressures, they told Science.
Survival benefit
Each gene variant emerged around the same time as the advent of so called "cultural" behaviours.
The microcephalin variant appeared along with the emergence of traits such as art and music, religious practices and sophisticated tool-making techniques, which date back to about 50,000 years ago.
It is now present in about 70% of humans alive today.
The other, called the ASPM variant, originated at a time that coincides with the spread of agriculture, settled cities and the first record of written language.
Cognitive neurologist Dr Geraint Rees
Researcher Dr Bruce Lahn said the big question was whether the genetic evolution seen had actually caused the cultural evolution of humans or was merely chance.
Their hunch is that it might have something to do with the important role that these genes play in brain size, but stressed that did not necessarily mean better intelligence.
"Just because these genes are still evolving doesn't necessarily mean they make you any smarter," said Dr Lahn.
Ongoing changes
But he added: "Our studies indicate that the trend that is the defining characteristic of human evolution - the growth of brain size and complexity - is likely still ongoing.
"If our species survives for another million years or so, I would imagine that the brain by then would show significant structural differences from the human brain of today."
The researchers said the next step was to examine whether biological differences imparted by the genetic differences caused natural selection to favour that variation over others.
They must have conferred some evolutionary advantage, such as a desired change in cognition, personality, motor control or resilience to neurological or psychiatric diseases, they said.
Dr Geraint Rees, a cognitive neurologist at University College London and Wellcome Trust senior research fellow, said: "It's very interesting.
"I do find it surprising that they can pinpoint these changes to a point relatively recently in evolutionary history.
"It gives us a clue to perhaps follow up on and try and understand why they emerged at that time and what the consequences were."
He said it would be too big a leap now to conclude that the genetic changes were responsible for some of the cultural changes we have seen, such as the emergence of agriculture. "But that's a tantalising prospect," he said.
http://news.bbc.co.uk/1/hi/health/4222460.stm
Kind regards
Nick
Posted by SLS on September 10, 2005, at 13:28:01
In reply to 'Proof' our brains are evolving, posted by Nickengland on September 9, 2005, at 18:54:25
> 'Proof' our brains are evolving
>
> The changes presumably confer a survival benefit
> University scientists say they have found strong proof that the human brain is still evolving.
What might be sad about the process of natural selection at work on the human brain is that it is now being driven by cultural and socioeconomic factors that select against the poor, uneducated, unwanted, and "unintelligent".
- Scott
Posted by Nickengland on September 10, 2005, at 14:05:24
In reply to Re: 'Proof' our brains are evolving, posted by SLS on September 10, 2005, at 13:28:01
I wonder if the proof is that our minds are still evolving, in time to come will there be new mental illness created along with the evolving nature of the human mind..
But with the added survival intelligence would we then be able to cure that mental illness?
Now my mind starts to go in to overdrive thinking of this lol - I am reminded of this saying..
"If the human mind was simple enough to understand, we'd be too simple to understand it."
Kind regards
Nick
Posted by Ilene on September 10, 2005, at 17:44:05
In reply to Re: 'Proof' our brains are evolving, posted by SLS on September 10, 2005, at 13:28:01
> > The changes presumably confer a survival benefit
> > University scientists say they have found strong proof that the human brain is still evolving.
>
>
> What might be sad about the process of natural selection at work on the human brain is that it is now being driven by cultural and socioeconomic factors that select against the poor, uneducated, unwanted, and "unintelligent".
>
>
> - Scott
>
Selection against these people would only be working if they had fewer children than the rich, educated, desirable, and intelligent. Lots of poor people have children.I.
Posted by SLS on September 10, 2005, at 18:38:31
In reply to Re: 'Proof' our brains are evolving, posted by Ilene on September 10, 2005, at 17:44:05
> > > The changes presumably confer a survival benefit
> > > University scientists say they have found strong proof that the human brain is still evolving.
> >
> >
> > What might be sad about the process of natural selection at work on the human brain is that it is now being driven by cultural and socioeconomic factors that select against the poor, uneducated, unwanted, and "unintelligent".
> >
> >
> > - Scott
> >
> Selection against these people would only be working if they had fewer children than the rich, educated, desirable, and intelligent. Lots of poor people have children.Several questions arise. Are the poor more likely to breed with the poor? If so, this becomes a closed breeding population separate from the rest of society wherein there might be less demand for intelligence to perform the jobs offered it. There is less selective pressure for the development of intelligence. Wow. That almost sounds like racism to me. Do the same percentage of children of the poor go on to successfully breed and raise similarly successful breeders? I don't know. All I do know is that evolution is not a universal teleological process of improvement. Not all breeding populations will have bestowed upon them the same progression of advantages and disadvantages simply because they are Homo Sapiens. I think much of what can be inferred from the article posted is that culture is indeed a modulator of evolution, and that the differences between the cultures of the poor and the wealthy might be different enough to act as modulators.
- Scott
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