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Monday, May 18, 2009

Archaic Homo sapiens

Cro-Magnon 1 skull, dated to 30,000 years ago (Upper Paleolithic).

The term Archaic Homo sapiens refers generally to the earliest members of the species Homo sapiens. Fossils categorized as archaic Homo sapiens have many of the same features as modern humans with general tendencies toward features of earlier Hominina species.

Archaic Homo sapiens lived during the Wolstonian, Eemian, and Devensian stages of the Pleistocene (300,000 to 30,000 B.P.). They were seemingly well adapted to different environmental stresses, as evidenced by the wide distribution of their tool and fossil remains. Their brains were larger than those of Homo erectus, and were comparable in size to those of modern humans.

There is some debate about whether Homo heidelbergensis or Homo neanderthalensis should in fact be classified as Homo sapiens. Some anthropologists hold that although they do have some anatomical similarities, they are not in fact of the species H. sapiens. They suggest that these different groups of hominids should be designated as their own, separate species. The earliest undisputed presence of H. sapiens is ascertained from ca. 160,000 BP with Homo sapiens idaltu. The most recent common matrilineal ancestor of humans alive today lived at about that time as well (ca. 150,000 BP).

Between 400,000 years ago and the second interglacial period in the Middle Pleistocene, around 250,000 years ago, the trend in cranial expansion and the elaboration of stone tool technologies developed, providing evidence for a transition from H. erectus to H. sapiens. In the Recent African Origin scenario, migration within and out of Africa eventually replaced the earlier dispersed H. erectus. Homo sapiens idaltu, from Ethiopia, lived from about 160,000 years ago. It is the oldest known anatomically modern human.

Fossils of modern humans were found in a cave in Israel at Qafzeh and have been dated to 100,000 years ago. However these humans seem to have either gone extinct or retreated back to Africa 80,000 - 70,000 years ago, possibly replaced by south-bound Neanderthals escaping the colder regions of ice age Europe. All other fossils of fully modern humans outside of Africa have been dated to more recent times. The next oldest fossil of modern humans outside of Africa are those of Mungo Man found in Australia and have been dated to about 42,000 years ago



Behavioral modernity

Cave painting from Lascaux, France dated to approximately 16,000 years ago (Upper Paleolithic).

Though fossil remains of modern humans appear about 200,000 years ago, significant changes in technology do not appear until much later. Beginning about 100,000 years ago, evidence of more sophisticated technology and artwork begins to emerge, and by 50,000 years ago fully modern behaviour becomes more prominent. By this time the ritual burying of the dead is noted. Stone tools show regular patterns that are reproduced or duplicated with more precision. Tools made of bone and antler appear for the first time. These new changes are suggestive of more advanced behaviour and scientists attribute these changes to the development of language[who?]. The new stone tool types have been described as being distinctly differentiated from each other as if each tool had a specific name. This period is referred to as the Upper paleolithic. For the first time in the fossil record evidence of fishing indisputably appears in Africa at 50,000 years ago. Homo erectus and the Neanderthals lived alongside oceans, rivers and lakes but never ate fish, though recent finds along the northern coast of the Mediterranean indicate that isolated clans of Neanderthal did consume ocean resources. Archaeological coastal sites that are dated to before 50,000 years contain no fish bones whereas those dated to after 50,000 do contain fish bones. This also serves as evidence for significant change in human behaviour at the 50,000 year mark.

Cultural universals are the key elements shared by all groups of people throughout the history of man. Examples of elements that may be considered cultural universals are language, religion, art, music, myth, games, and jokes. These traits distinguish homo sapiens from other species. David Buller hypothesizes that some cultural universals may in fact be cultural homologies that originate from a common human ancestry. Nicholas Wade writes:

Yet the ancestral population, even if generally inclined to aggression, presumable possessed all the major elements of human behavior that occur in descendant populations around the world, since otherwise all of these behaviors would have had to evolve or be invented independently in each of thousands of societies
Whatever the genesis of these universals, the fact that they are found in societies throughout the world suggests strongly that they would have been possessed by the ancestral human population before its dispersal.

Origin of language

There is considerable debate regarding when modern human language first came into existence. Much of the debate centers on whether modern language arose suddenly with anatomically modern humans or whether language developed gradually over millions of years with all archaic hominids. Those in favor of the "sudden occurrence" of language argue that the first indisputable signs of symbolism such as art, which are associated with language, occur in the fossil record 50,000 BP, and become significantly more abundant thereafter. They contend that language was a necessary prerequisite for modern humans to leave Africa and reach continents such as Australia, that had never before been populated by Archaic hominids. Since all these major historic events appear to take place around the 50,000 year mark, scholars believe this is when language suddenly arose, with some suggesting that it may have required some biological change such as a mutation affecting the brain.

Other schools of thought disagree with the sudden emergence of language. They argue that since only a few materials such as bone and stone fossilize, the lives of archaic hominids may have involved the use of several materials that do not fossilize, such as wood or bark. Hence it would be impossible to concretely ascribe a date to the first symbolism. In addition a few fossils that appear to be symbolic have been controversially dated to much earlier than 50,000 BP. These include the Katanda bone points from the Congo, dated to 100,000 years ago and engravings found on red ochre dated to 75,000 years ago from Blombos cave in South Africa. This would indicate that language may have arisen much earlier. However these findings are disputed with some arguing that they are simply anomalies in the fossil record.

Since the human line branched off from the common ancestor shared with chimpanzees six million years ago, the human vocal tract has been evolving. Hence some scholars argue that it must have been evolving for a reason. If the Neanderthals possessed a near modern if not fully modern vocal tract, then it would only make sense that it must have evolved for them to use some sort of speech. However critics once again point to the Neanderthal stone tool kit.


Physical appearance

The majority of apparent difference in human physical appearance around the world, or what may also be called racial features, can also be explained through the process of regional sexual selection.

The general consensus among scholars is that dark skin, coupled to loss of body hair, evolved some 1.2 million years ago, well before the emergence of Homo sapiens. The SLC24A5 mutation resulting in light skin is currently estimated to have originated among Europeans some 6,000 to 12,000 years ago.


Fossils

  • Omo remains, 200ka, Ethiopia
  • Jebel Irhoud, 160ka, Morocco
  • Qafzeh, 100ka, Israel
  • Mungo Man, 42ka, Australia
  • Hofmeyr Skull, 36ka, South Africa
  • Cro-Magnon 1, 30ka, France

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