Jaws and Brains

K

Konek

Lazy user
Registered Senior Member
From Today's Nature Science Update:
"A mutation 2.4 million years ago could have left us unable to produce one of the main proteins in primate jaw muscles... Lacking the constraints of a bulky chewing apparatus, the human skull may have been free to grow, the researchers say."

Basically, we exchanged chewing abilities for larger brains. Any thoughts?
 
John Connellan said:
There are lots of theories really. That is one of them.
Click to expand...
Well, it's a bit more than that.

It's a paper with comparative data (I mean real data) and published in one of the (if not the) top scientific journals in the world.

I can supply the article electronically (.pdf format) if anyone wants.
 
what i can't understand is how we developed such a massive use of technology?
I can see how having the smaller jaw would make our brains bigger over time, but why did those bigger brains choose to make tools? how did that happen?
 
This is a mutation that took place 2.4 million years ago, before race differenciation. The same mutation on the same gene is found in at least six geographically distinct human populations.

Regarding the amount of technology acheived, a lot of it might have been triggered by the need for tools, since the jaws were now useless for a number of things, like breaking nutshells of biting opponents.

Thanks for the SciAm article, by the way. If anyone wants to get good explanations on why some populations were unable to produce their own technology, I recommend Jared Diamond's "Guns, Germs and Steel".
 
Jaws, and brains........ why do they do have something?
Okay, here's a light problem about jaw-brain connection, I wonder if this happens to you too:
If I shut and forcefully press my jaws to each other, I feel a movement on the side part of my head, the part is rather close to the spot on which I can sense my 'beat' (aw, damn, I'm bad at terms.... basically the blood movement you feel like when you place your hand on your inner wrist). Explanation?
 
Konek said:
From Today's Nature Science Update:
"A mutation 2.4 million years ago could have left us unable to produce one of the main proteins in primate jaw muscles... Lacking the constraints of a bulky chewing apparatus, the human skull may have been free to grow, the researchers say."

Basically, we exchanged chewing abilities for larger brains. Any thoughts?
Click to expand...

thought:

It would seem that we would have required the large brain before the muscle mutation. Otherwise it would have been selected out quite quickly.

Does that sound reasonable?
 
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spuriousmonkey said:
thought:

It would seem that we would have required the large brain before the muscle mutation. Otherwise it would have been selected out quite quickly.

Does that sound reasonable?
Click to expand...

I wonder about that one too. If this mutation came about before we started making tools, how did it help outcompete the non-mutants? I mean, the first generations would have had no advantage over the rest, rather they would have been in trouble when fighting or even feeding themselves.

Paul, I misunderstood your first post, but thanks anyway.

By the way, width is not the same as weight. Einstein's brain weighed only 1,230 grams, which is less than the average adult male brain (about 1,400 grams). Not that it matters.
 
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spuriousmonkey said:
thought:

It would seem that we would have required the large brain before the muscle mutation. Otherwise it would have been selected out quite quickly.

Does that sound reasonable?
Click to expand...

I agree. I think that mutation was more like a reservoir break than a trigger to brain/human evolution... I guess that's the opinion of C. Owen Lovejoy, by his quote in this Yahoo news:

"Such a claim is counter to the fundamentals of evolution," said C. Owen Lovejoy of Kent State University. "These kinds of mutations probably are of little consequence."
Click to expand...

http://story.news.yahoo.com/news?tmpl=story2&u=/ap/20040325/ap_on_sc/the_human_gene&e=2

If not, that should be what the middle grounders, cited short after only as "others", think of it.
 
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