Neanderthal DNA

[Digit]

But did that part of Africa that we are all supposed to have sprung from actually get cooler?
If so did it have sufficient effect on the climate there to trigger a response?
Reading the link, the reverse of their conclusions would mean that those who remained in Africa didn't get any brainier?

[Forum Monk]

This makes some sense I guess. From the Daily Grail.

Really? They haven't gotten smaller have they? What about now when the most challenging thing we have to face is whether to watch channel 3 or channel 8? Our brains should be about the size of gnats by now.

Also, why do other animals not have the same tendancy toward bigger brains?

[Digit]

Why the devil Monk can't these self proclaimed experts ask these questions?
Going back to your comments about education, in some cases it seems to destroy common sense.

[Beagle]

I'm not defending the article, as it seems a bit simplistic,, but humans have no other way to compete in the food chain except with their brains.
We don't have the size, strength, speed, claws, horns, or anything else except the brain.

So I can buy into the idea that the more challenging the environment, the brainier one has to be to survive.

Unlike today, as Monk mentioned, when we are in a period of brain atrophy.

[Cognito]

We don't have the size, strength, speed, claws, horns, or anything else except the brain.

The human species is not as physically challenged as you might think. A California Mojave Indian "runner" could easily run down a horse for food if he wanted ... it was just a matter of running after it for a minimum of 20 miles until it was exhausted. It's not as difficult as running 50 miles a day to get somewhere fast. The human is already a successful predator, but an organized, large brain makes it top predator.

[Minimalist]

Unlike today, as Monk mentioned, when we are in a period of brain atrophy.

There you go again. Always talking about Bush.

[Digit]

The weakness in the idea as I see it folks is as Monk pointed out the other animals, which in general would have a less varied diet, didn't become brainier or become extinct, and as I pointed out the statement says that the further from the tropics the more pronounced the effect. Unless the IQ of people in the Rift Valley is less than a northern European an explanation is required.
In addition I'll go out on a limb again and suggest that a large brain is not necessary for survival, in fact its energy requirements make it a distinct disadvantage.

[Minimalist]

A California Mojave Indian "runner" could easily run down a horse for food if he wanted

But, if he had not previously invented useful tools like a spear or knife, what would he be able to do with it when he caught it? Without weapons, my money is on the horse in any subsequent hand-to-hoof combat.

[Forum Monk]

Without weapons, my money is on the horse in any subsequent hand-to-hoof combat.

Correct. If you don't have weapons you go for something small like rabbits. But you're not going to feed the village.

Digit has made a good point about size. If brain size = intelligence when do you reach the point of diminishing returns. The human brain is one of the largest energy and oxygen consumers in the body and hence requires copius blood supplies. Since there's very little insultation in the head (fat heads are considered unintelligent anyway), heat is lost through the head. On the surface is doesn't appear as a good ice age survival tactic, that evolution would choose.

[Beagle]

That's right. We lose fully 20% of our body heat through our heads.
Everything in nature has a cost/benefit factor.
With our large brains we found a way to cover our heads in cold weather though. Although we don't have any direct evidence that a Neandertal did that, we are gifted with the common sense to know that he did. As did ancient eskimos.

[Cognito]

But, if he had not previously invented useful tools like a spear or knife, what would he be able to do with it when he caught it? Without weapons, my money is on the horse in any subsequent hand-to-hoof combat.

Min, you have a good point except that after 20 miles the horse very often falls over and dies from exhaustion. Humans have a far greater capacity for long distance running than horses. Regardless, the Mojave still needs a knife and fire to cut up the food and cook it, and those were the result of brainpower. I therefore yield to the crowd's consensus.

[Minimalist]

If there is anything to Out of Africa then evolution did not choose it. The ice never reached that far south.

If HSS entered Europe at 40,000 BC then the ice age was well underway when they got there. Perhaps the big brain merely allowed them to adapt.
It's one of the big problems that I have with the Toba bottleneck theory.
If any species was adaptable it was HSS. Animals which look for one type of vegetation or prey might have been screwed...should have been screwed, really. Humans, though, can and do eat whatever they can find.

[Forum Monk]

Humans, though, can and do eat whatever they can find.

This is just screaming for a joke...but I'll refrain from cherry picking.

[Cognito]

If there is anything to Out of Africa then evolution did not choose it. The ice never reached that far south.

If HSS entered Europe at 40,000 BC then the ice age was well underway when they got there. Perhaps the big brain merely allowed them to adapt.
It's one of the big problems that I have with the Toba bottleneck theory.
If any species was adaptable it was HSS. Animals which look for one type of vegetation or prey might have been screwed...should have been screwed, really. Humans, though, can and do eat whatever they can find.

So Min, the other unexplainable event is modern humans being in Israel about 100,000bp, then disappearing. Neanderthals reoccupy Israel until OOA about 60,000bp. If modern humans were so competitive, etc. why did they retreat from Israel only to be replaced by Neanderthals? What happened?

[Digit]

The big brain allowing us to adapt has always been the cornerstone of my arguments Min and was guaranteed to get marduk screaming. Putting a species under pressure is not going to make it produce anything, that selective pressure will select for those that already have the means for adaption. In other words our brain size enabled us to cope where other species failed, but it always leaves me wanting to know why the big brain, with its inherant disadvantages, ever arose in the first place, a Chimp manages perfectly well without.