Posted on 06/11/2003 8:03:26 AM PDT by blam
Oldest human skulls found
By Jonathan Amos
BBC News Online science staff
Three fossilised skulls unearthed in Ethiopia are said by scientists to be among the most important discoveries ever made in the search for the origin of humans.
Herto skull: Dated at between 160,000 and 154,000 years old (Image copyright: David L. Brill)
The crania of two adults and a child, all dated to be around 160,000 years old, were pulled out of sediments near a village called Herto in the Afar region in the east of the country.
They are described as the oldest known fossils of modern humans, or Homo sapiens.
What excites scientists so much is that the specimens fit neatly with the genetic studies that have suggested this time and part of Africa for the emergence of mankind.
"All the genetics have pointed to a geologically recent origin for humans in Africa - and now we have the fossils," said Professor Tim White, one of the co-leaders on the research team that found the skulls.
"These specimens are critical because they bridge the gap between the earlier more archaic forms in Africa and the fully modern humans that we see 100,000 years ago," the University of California at Berkeley, US, paleoanthropologist told BBC News Online.
Out of Africa
The skulls are not an exact match to those of people living today; they are slightly larger, longer and have more pronounced brow ridges.
These minor but important differences have prompted the US/Ethiopian research team to assign the skulls to a new subspecies of humans called Homo sapiens idaltu (idaltu means "elder" in the local Afar language).
Herto reconstruction: What the ancient people might have looked like (Image copyright: J. Matternes)
The Herto discoveries were hailed on Wednesday by those researchers who have championed the idea that all humans living today come from a population that emerged from Africa within the last 200,000 years.
The proponents of the so-called Out of Africa hypothesis think this late migration of humans supplanted all other human-like species alive around the world at the time - such as the Neanderthals in Europe.
If modern features already existed in Africa 160,000 years ago, they argued, we could not have descended from species like Neanderthals.
"These skulls are fantastic evidence in support of the Out of Africa idea," Professor Chris Stringer, from London's Natural History Museum, told BBC News Online.
"These people were living in the right place and at the right time to be possibly the ancestors of all of us."
Sophisticated behaviour
The skulls were found in fragments, at a fossil-rich site first identified in 1997, in a dry and dusty valley.
Stone tools and the fossil skull of a butchered hippo were the first artefacts to be picked up. Buffalo fossils were later recovered indicating the ancient humans had a meat-rich diet.
The most complete of the adult skulls was seen protruding from the ancient sediment; it had been exposed by heavy rains and partially trampled by herds of cows.
SEARCH FOR HUMAN ORIGINS
The Herto skulls represent a confirmation of the genetic studies
The skull of the child - probably aged six or seven - had been shattered into more than 200 pieces and had to be painstakingly reconstructed.
All the skulls had cut marks indicating they had been de-fleshed in some kind of mortuary practice. The polishing on the skulls, however, suggests this was not simple cannibalism but more probably some kind of ritualistic behaviour.
This type of practice has been recorded in more modern societies, including some in New Guinea, in which the skulls of ancestors are preserved and worshipped.
The Herto skulls may therefore mark the earliest known example of conceptual thinking - the sophisticated behaviour that stands us apart from all other animals.
"This is very possibly the case," Professor White said.
The Ethiopian discoveries are reported in the journal Nature.
Now that would be cool.
You never know though. Someone found an unknown manuscript by Mozart in an attic in Wisconsin a year or two ago.
Galileo's daughter's letters were just published in English a couple years ago as well.
g'nite
No. Changes in allele frequence and selection. At least you should describe evolutionary theory correctly.
Can you locate the tangible evidence that constitutes the subject matter of quantum physics and shine a flashlight on it? Do you have tangible evidence that gravity operates in the intergalactic void? Based on what tangible observations of objects therein?
Indeed. Think of it. It appears to explain fossil "gaps", doesn't it?
On the other hand, DNA might prove to be more useful. Maybe it does show a line of transendency between the species?
Hmm. Well, you're a little late to the dance. The gross correlation between the fossil record and that DNA mutational distance relationships has been one of the really big newsflashes for going on 30 years now. Look up the work of Woese, based upon which the Tree of Life was officially revised at it's root, from three families, to 5 domains, quite recently.
There's one kind of DNA known, and some DNA chromosomes are packaged for work in the nucleous, and some kinds are packaged for work in mitochondria, and some kinds are packaged for work in other organelles, as well.
From evaluations of numerous critters we know--thanks to various mutational distance calculations now available to us, to be in our predecessor chain--that we have been steadily leaking chromosome packages out of their mitocondrial containers and into the nucleous over time. Quite a trip for a chromosome, in my humble opinion.
Super human would be more like it. They had, on the average, about 1/5 more brain volume than we do, and were built like tree stumps--possibly from wrestling with trees, as their bone bones aren't just bigger than ours, they show far more frequent, and deeply persistent signs of trauma than our remains typically show.
Speculation is rife that we see this because they made their livings in a much more demanding style than we typically did--this style divergence is not so pronounced in sites closer to the equator we have recovered, but it's distinct in Northern digs. It's not just that they were bigger--they were bigger for some reason that diverged their effective environment from ours substantially. My favorite thesis about this is that Neanderthals never evolved being-at-war from hunting, like we did, with armament stores, advanced provisioning, and permanently scheduled raiding parties--they just wrestled down a polar bear or two whenever they were hungry.
It is tempting to suppose that the reason they diverged from our branch of the family in the first place, is that they came to be making their livings up north, where hunkering in shelter punctuated by the occasional big jackpot kill made more sense than the military approach we took to sweeping the hot veldt for sustenance on an organized daily basis.
Looking at their bones and our bones side by side, I find it extremely hard to take seriously the notion that they were just the gridiron guards of the human species. They were big honkers, and I just cannot visualize how their flesh could have hung off those frames in a manner that puts me in mind of my grandpa, the logging camp mule-skinner, even in his prime.
I meant to say "chromosomes", not "kinds", of course.
Sorry.
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