Friday, March 19, 2010

Cro Magnom Skull 20% Larger

For whatever reason, European versions of homo sapien sapien were robust during the Pleistocene.  Their contemporary was as robust.  Six foot heights appear normal and here we have evidence of a larger brain than typically expected.

The earth of the Pleistocene was well populated with humanity in both hemispheres.  They certainly universally appeared to live as hunter gatherers and not as herders.  More settled populations lived on the coastal lowlands but these are all submerged three hundred feet.

Inland we have huge game herds and their powerful hunters.

In the end, we still have far too little evidence to know if the skull is exceptional. 

Robust hunter gatherers do not exist today.  Their game herds no longer exist either.  Agricultural man shrank in response to a combination of conditions now been superseded.  Late child bearing and generational progression with sufficient food is again producing larger human beings

Our men in the modern era are shaking out between six to six and a half foot tall and shoulder s and musculature is following.  We will be producing plenty of six foot Tarzans during the next few years.  The genetic potential was always there, but obviously suppressed in a society of scarcity.  It is worth noting that this resizing is also taking place among Chinese and other unexpected groupings.  It will take about three generations to be well expressed.

It appears that Eurasian man as hunter gatherer was typically six foot tall and robust perhaps explaining measured brain size.  Subsistence agriculture shrunk him down.

Replica of big skull from 28,000 years ago suggests human brains have started to shrink

Last updated at 2:40 PM on 14th March 2010

Our brains are shrinking, according to scientists who have recreated a 28,000-year-old skull from remains found in France.

The French team, which claims to have produced one of the best replicas yet of an early modern human’s cranium, says it is up to 20 per cent bigger than ours.

No one is suggesting this means our ancestors were more intelligent as studies have found there is only a minor link between brain size and IQ.

Instead, it is believed the skull, called Cro Magnon 1 after the caves in the Dordogne where it found, suggests our brains are becoming more efficient like shrinking computers.

But the project could shed light on a human evolutionary question that has divided and bemused the specialists: if our heads have started to shrivel, why is this happening?

Cro Magnon 1 has been kept in the French National Museum of Natural History in Paris since it was discovered among five ancient skeletons in 1868.

It is thought to have been a well-built, elderly man about 6ft tall.

Already known to scientists worldwide, Cro Magnon 1 will become even more famous next week when a mold of his skull will be shown at the American National Museum of Natural History in Washington.

The endocast was made by scanning the interior of the skull at the Quinze-Vingts Hospital in Paris to obtain a picture of the impression left by the brain on the neurocranium.

Antoine Balzeau, of the French Museum of Natural History, transformed this into a 3D image that was in turn made into a mold by a specialist software prototyping firm.

‘It’s one of the most beautiful endocasts ever,’ Mr Balzeau told The Times.

He said that an initial assessment of Cro Magnon 1’s skull confirmed the belief that brains had grown ‘slightly smaller over tens of thousands of years’, reversing an earlier trend towards bigger brains. 

However, he said that the cerebellum — a brain structure linked to language and concentration — appears to take up a larger proportion of the head now than in the time of Cro Magnon 1.

This suggests that some parts of the brain are more ‘compressible’ than others, he said.
Several theories have been advanced to explain the mystery of the shrinking brain. One is that big heads were necessary to survive Upper Paleolithic life, which involved cold, outdoor activities.

A second theory is that skulls developed to cope with a chewy diet of rabbits, reindeer, foxes and horses.

As our food has become easier to eat, so our heads have stopped growing, according to supporters of this theory.

Other experts say that with high infant mortality, only the toughest survived — and the toughest tended to have big heads.

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