The Human Wave

Science News Magazine ^ | 8-11-2005 | Bruce Bower

[hosepipe]

I meant PEDERASTY... LoL... The drain bamage is getting much better.... really..

[PatrickHenry]

It's the female version of the Thomas Jefferson-Sally Hemmings controversy.

[curiosity]

I more inclined to believe Excoffer's theory than the others. I just don't buy the idea of widespread miscegenation with Homo Erectus. Why would sane person mate with something that has a brain less than 3/4 the size of a human's?

I am much more inclined to believe miscegenation with Neaderthals, but even there the evidence is that there was very little, if any.

[PatrickHenry]

Why would sane person mate with something that has a brain less than 3/4 the size of a human's?

Never spent much time in singles bars, did you?

[shuckmaster]

I just finished reading Oppenheimer's The Real Eve and this article seems to contradict it on several points. Oppenh seems to think modern humans started about 200kya and spent the first 150k almost strictly as beachcombers who came out of Africa 85kya and started turning inland into Asia and Europe about 60-50kya. Reading between the lines, advanced toolmaking came not from advanced intelligence but from necessity to adapt to the new inland terrain. IOW, they didn't need intricate tools to gig flounder and pry open oysters, etc; even though they had the intelligence to adjust when necessary

Oppenheimer says no way to cross breeding with earlier erectus/neanderthal etc. This article seems to strongly suggest that the crossbreeding did go on which seems more likely to me.

Another problem I have with Oppenh is that all his routes seem to go one way with little or no backtracking except when forced by ice ages. Humans had all ready evolved as perpetual long distance runners and quite capable swimmers well before 200kya and living on the shores gave them practically unlimited opportunity to run & swim both ways.

[Coyoteman]

I more inclined to believe Excoffer's theory than the others. I just don't buy the idea of widespread miscegenation with Homo Erectus. Why would sane person mate with something that has a brain less than 3/4 the size of a human's?

How do you account for the line traits (shovel-shaped incisors, etc.) in Peking Man which persisted through to modern Mongoloids? I have never seen a good explanation for that, spanning some 500,000 years.

When I went to school, modern man was some 40,000 years or so old, and my professor, a brilliant but older researcher, couldn't accept the 200,000 year old fossils as fully modern. Now we all accept modern humans at some 200,000 years ago, and can even trace their progress. This new theory fills in the question that has always bothered me about shovel-shaped incisors in Peking Man. Your thoughts?

[curiosity]

I'm serious. Preference for large-brained mates was one of the factors that caused us to evolve large brains. Now suddenly, when humans meet H. Erecti, their mating preferences change and they decide to go slumming? Does't make any sense.

Besides, why would there be widespread micegenation with Erectuses but not Neanderthals? That also makes no sense.

Sorry, I just don't buy it.

[curiosity]

How do you account for the line traits (shovel-shaped incisors, etc.) in Peking Man which persisted through to modern Mongoloids?

From the article (Excoffier's hypothesis):

"A small number of those fledgling people then migrated to Asia. As the population expanded, separate groups formed in different areas...Some ancestral genes could have been carried out of Africa, while being lost within Africa. That would explain why Asians carry much older stretches of DNA than Africans do."

That would seem it would also explain the shovel-shaped incisors. They were present in the ancestoral population in Africa, but later lost.

[Coyoteman]

That would seem it would also explain the shovel-shaped incisors. They were present in the ancestoral population in Africa, but later lost.

I have never heard of any sizeable (>2-3%) numbers of shovel-shaped incisors in Africa. I am still confused. I understand the Lapps or some group in that area had a slightly higher percentage, but the real mother-lode is in the Mongolian group, and in Peking Man. Help?!?

[curiosity]

I'm not a paleantologist, but here is the hypothesis as I understand it. Only a small subset of the African ancestral population, maybe as low as 2-3%, had these Mongoloid traits. The group that migrated to Asia was from this subset. The descendent population surived in Asia but the ancestral population in Africa died out.

Fire away if you see any holes.

I'm also curious how you deal with my serious objection to the erectus micegenation hypothesis in post 27.

[Coyoteman]

I did this field, bones mainly, in grad school lo these many years ago. Things have changed a lot since then.

erectus micegenation hypothesis in post 27

Have to study that one. Don't have any idea at present.

Only a small subset of the African ancestral population, maybe as low as 2-3%, had these Mongoloid traits. The group that migrated to Asia was from this subset.

That would place these traits in somewhat the same ratio in Asia. You would need extreme founder's effect to (1) get this in large percentages throughout Asia, and even more radical measures to (2) get it into Peking Man, some 500,000 years ago. That's my problem. If modern man is 200,000 thousand or so coming our of Africa, without a significant percentage of shovel-shaped incisors, and current Mongoloids have a high percentage of shovel-shaped incisors, and Peking Man has shovel-shaped incisors along with modern traits--how do it all work?

I'm serious here. This has always confused me. Any help would be appreciated. (But now to bed; responses tomorrow.)

[JimSEA]

Good article, can be related to with Milford H.Wolpoff and Rachel Caspari's Race and Human Evolution in some aspects.

[curiosity]

That would place these traits in somewhat the same ratio in Asia.

Sorry, I was unclear. The number of modern humans in Africa with the traits was small, perhaps concentrated in a few tribes. ONLY individuals from these tribes migrated to Asia. That's why the ratios are so much higher in Asia.

In addition, the starting ratios in Africa don't have to be as small as today. It could be that the original ratio was higher, but then the Mogoloid-trait Africans that stayed behind declined, leaving the very small ratio we have today.

You would need extreme founder's effect to (1) get this in large percentages throughout Asia, and even more radical measures to

You would obviously need a founder effect, but I don't see why it has to be extreme.

That's my problem. If modern man is 200,000 thousand or so coming our of Africa, without a significant percentage of shovel-shaped incisors, and current Mongoloids have a high percentage of shovel-shaped incisors, and Peking Man has shovel-shaped incisors along with modern traits--how do it all work?

You would have to have mongoloid traits existing in the ancestral African H. Erectus too. The Peking Man was then simply a decendent of migrants from the Afrrican erectus population.

Is there any evidence that the mongoloid traits were significantly more common in the Asian erectus populations than in African erectus populations? I thought Peking man was just one specimen.

[RightWingAtheist]

Oh, so you didn't have any luck there either. Glad I'm not the only one :)

[blam]

"That's my problem. If modern man is 200,000 thousand or so coming our of Africa, without a significant percentage of shovel-shaped incisors, and current Mongoloids have a high percentage of shovel-shaped incisors, and Peking Man has shovel-shaped incisors along with modern traits--how do it all work?"

There are two types of 'shovel-teeth'. They are: Sundadonty and Sinodonty, the South East Asians have sundadonty teeth (named for Sundaland) and the North Asian have Sindodonty teeth. Oppenheimer said his DNA studies showed that sinodonty, flatter faces, lighter skin and the peculiar eye lid evolved (around Lake Bailal)from the folks in the south with the Sundadonty teeth.

IIRC, Kennewick Man had Sundadonty teeth while today's American Indians have sindodonty teet.

[blam]

"Why would sane person mate with something that has a brain less than 3/4 the size of a human's? "

You mate with what's available, huh?

Also, brain sizes have been on the decline for quite a while. Neanderthals and Cro-Magnons (and, maybe Homo-Erectus) had larger brains that humans today. There is a close link between IQ and brain size, so...

[curiosity]

Erectus had larger brains? Really? That's the first I heard. I remember being taught their brains were only about 70% of ours on average, with perhaps some of their outliers overlapping with some of ours. Am I wrong?

[curiosity]

So do any African erectus specimens have Sundadonty teeth?

[blam]

"Erectus had larger brains? Really? That's the first I heard. I remember being taught their brains were only about 70% of ours on average, with perhaps some of their outliers overlapping with some of ours. Am I wrong?"

Nope, you're correct. Ironically, I'm watching 'Apes To Man' on the History Channel and they just said that Homo-Erectus's brain was two-thirds the size of modern Humans.

The 'Hobbits' (on Flores Island) have a small brain and the shape most closely resembles the Homo-Erectus brain however, they have a Broca's Area that is four times larger than our Broca's Area.

[blam]

"So do any African erectus specimens have Sundadonty teeth?"

I've wondered the same thing, I don't know. Christy Turner did some studies on teeth but I don't think he covered that area. Try a search on Christy Turner + teeth, that may get you an answer.