Saturday, November 10, 2012

So What's the Deal with the Neanderthal, Their Demise? - 2

This a carry-over topic from a previous installment: So What's the Deal with the Neanderthal, Their Demise?

To recap:

Were contemporary modern humans, you know—the species that lives on to this day, responsible? Or did everything else that was working fine for the Neanderthals' survival, prior to the arrival of the so-called anatomically modern humans, came to a halt for some reason or another?

Introduction: 

The discovery of  Neanderthal remains [see the entry: How are the Media and Schools catching up with Scientific Progress? Pt.4] has naturally raised the curiosity of people, because they seem so close to us humans, and so, many inquiring minds want to know what happened to these extinct human cousins. Preexisting evidence so far only presents sketchy explanations of not only exactly how they (Neanderthals) reached their extinction, but also precisely where and from what ancestral line [although there are guesses as to what that might be] Neanderthals emerged. Notwithstanding significant strides made in the discipline of molecular genetics, as well as new findings in human paleontological record, researchers are still battling out the search for the most solid and parsimonious answers to those main aforementioned fronts.

Where the demise of the Neanderthal is concerned, there have been suspicions of the role of modern humans in this within the scientific community for a while now, although there seemed to be an air of reluctance to want to explore that very possibility. To that end, the more popular narratives which have circulated the web for years, generally looked mostly to abrupt environmental shifts as the prime suspect in the demise of the Neanderthals, purportedly in accompaniment with the insufficient resourcefulness of the Neanderthal; the role of modern humans had generally taken somewhat of a back seat in such narratives.

Discussion: 

The discussion will pick up from where the previous segment left. In that first segment, the matter of the changing direction of the wind, in terms of how the Neanderthal is perceived in academia, was briefly looked at, and the launch of an examination of whether so-called "anatomically modern" humans had any role in the former's demise. Naturally, one of the first things to look at in pursuit of the answer(s), is the determination of any role of differences in either intellectual capacity and/or culture at the sub-species level in the way the evolutionary paths of the two human species have manifested. It is obviously hard to overlook the fact that the 'anatomically modern' human is the only human species that lives on to this day. It therefore follows that modern humans had the benefit of something that gave their sub-species an evolutionary upper hand. What could that something possibly be?

There is an emerging segment in academia which is getting more vociferous about the prospect of neither the intellectual nor behavioral capacity of the Neanderthal being significantly different or inferior to that of their 'anatomically modern' human contemporaries. If we were to give it the benefit of doubt and put the aspect of intellectual capacity aside, then one will have to explore the role played by culture and/or the impact of ecology. To this end, the discussion in the first segment looked at the possible role of technology. In the Upper Paleolithic context, much evidence of this is in the form of a variety of stone tools found in occupation sites that have been subject to archaeological scrutiny.

The picture that emerges, is that the Neanderthal and modern humans applied hunting equipment that were perhaps efficiently equivalent for a considerable amount of time, but that at some point in time, particularly in the Middle Stone Age or Upper Paleolithic, there was a shift in the variety of weaponry used by anatomically modern humans, first in Africa—as the home of modern humans, then elsewhere to which modern humans spread. John Shea has been cited quite a bit, because he represents one of those advocates in academia who seemingly strive to come across as resisting the urge of underestimating the Neanderthals vis-a-vis their modern human contemporaries, and he has extensively covered the issue of armature technology in prehistoric contexts, with respect to both the African and non-African records. It is therefore comes as no surprise that he is among researchers featured in such documentaries like the aforementioned "Clash of The Cavemen", 2008.

There is a widespread understanding in anthropological circles, that the Neanderthal were not prolific users of projectile weaponry, as indicated by paucity of associated evidence. This stands in contrast to the anatomically modern human record, in Africa and elsewhere. The last segment extensively covered, via Shea for example, the case made for considerable application of armature with "ballistically-significant" dimensions among modern humans' prehistoric arsenal, mostly dating to Middle Stone Age or the Upper Paleolithic, whereas European and "Near Eastern" [regions where Neanderthal remains have turned up] Middle Paleolithic record of equivalent time frame [mainly prior to 35-45 ky ago], came up short with such statistical assurance.

Function-identification of prehistoric stone tools, of course, has not been without challenges. For instance, "taphonomic biases against the preservation of such artifacts in tropical contexts makes it difficult to compare the evidence for bone tools between Africa and Eurasia (Henshilwood and Marean, 2003)," said John Shea. Researchers have also been afflicted with application of insufficient variables or discriminants in the pursuit of systematizing stone tool typology, compounded by compiling of specimens by analysts with poor understanding of their actual functions.

We know that anatomically modern humans who occupied the Americans by the late Upper Paleolithic, by ca. 15kya or so, already possessed projectile weaponry, as further indication that projectile armature was in regular use by such time, by anatomically modern humans in much of the area to which they spread. The atlatl for instance, comes to mind. Shea for his part, as noted, took care not to come across as harboring subjective bias against the Neanderthal, characterizing the apparent Upper Paleolithic technological differentiation between the Neanderthal and their modern human contemporaries as follows:

The suggestion of chronological priority for projectile weaponry in Africa begs the question, “Why Africa?” It is unlikely that there were uniquely derived evolutionary capacities that predisposed early African Homo sapiens populations to invent projectile weaponry. Ambrose (2001) has argued for a link between compound technologies (i.e. hafting) and language, but wear trace and residue evidence for hafting is now associated with Neandertals as well as with early Homo sapiens (Gr├╝nberg, 2002; Lombard, 2005a).

He only notes that,  "it is vastly more likely that projectile technology emerged first in Africa and dispersed rapidly among its human populations for contingent evolutionary and environmental reasons," and goes to pains to expand on this concept, with essentially various hypotheticals, which he apparently thought were the most plausible in encouraging modern humans in Africa to master this technology.

It's not just the matter of the role of contrasting technological development between the Neanderthal and their modern humans counterparts. There is evidence of physiological factors playing a possible role in the behavioral capacities of Neanderthals and modern humans respectively. Neanderthals unsurprisingly feature relatively stockier body build which seems to be a common theme among many terrestrial limb-bearing creatures of cold climes, sporting relatively low limb proportions that are generally below even the mean scores of recent European and the Upper Paleolithic (so-called Gravettian) 'anatomically modern' specimens, while exhibiting noticeably high values for body linearity measurements, featuring broader body trunks than recent humans, as indicated by their greater mean values reported for relative femoral head diameter and relative bi-iliac breadth.

Some visual aids, courtesy of T. Holliday:



Click on the images for higher resolution.

The Neanderthals closest neighbors are elements from the "recent European" collection, in the scatter "bivariate plot" for femoral bi-condylar length regressed on femoral A-P head diameter, which is understandable given that recent Europeans themselves are the outcome of modern humans who had undergone some adaptation [there's still some overlap between elements of 'recent Europeans' and 'sub-Saharan Africans'] to the cold climes of Europe. The same is true in the "bivariate plot" for relative bi-iliac breadth regressed on stature. The tenability of these scatter plots are further gauged by percentage deviations of predicted femoral lengths from the recent human regression lines.

In terms of "prediction errors" in femoral lengths from the recent human regression lines (represented by respective RMA/reduced major axis slopes) in the two bivariate plots, the highest percentage deviations—which were all in the negatives, corresponding to the bivariate plot for the relative femoral head diameter—were found for the Neanderthal sample; in both cases, the Neanderthals showed higher percentage deviations of femoral length from the so-called "sub-Saharan African RMA slope" than they did from the so-called "recent European RMA slope". This would not only point to the prospect of reasonable estimation of Neanderthal femoral lengths more closely approximating the recent European continuum than that of the sub-Saharan African collection, but also a high prospect for significance [statistical]  in the limb size differences between the Neanderthal collection and the recent human counterparts.

The contrast in body plans between Neanderthals and modern humans is correlated to the substantial habitation of the former in colder climes, and the tropical/equatorial-proximate origins of the latter. Now because of the aforementioned body plan of Neanderthals, it is alleged that they must required around 30% more energy expenditure than their modern human counterparts, just to implement the task of running. How that quantity of energy was determined isn't clear to the present author, but the general point is taken, which is to say that modern humans would have been faster runners than Neanderthals. Being the self-congratulatory creatures modern humans tend to be, perhaps could not be more clearer in the way History Channel's so-called documentary production, Clash of The Cavemen, makes this very point:

Narrator...
Ambush hunting works well in and around the forest, where it is easier to get close to prey without being seen, but in wide open spaces, the Neanderthals don't stand a chance, because unlike their more modern adversaries, they weren't born to run.

John Rennie - editor in chief, Scientific American...
It’s a little appreciated fact that we modern humans are actually among the best long-distance runners in the entire animal kingdom.

And if you look at modern humans, because we have much longer legs, because we have a pelvis that helps us distribute the weight of one step that bounces off into another step, we can actually manage to run extremely well.

It's why we can run marathons; most animals cannot.

Narrator...
In comparison to modern humans, Neanderthals have short limbs and a wide pelvis, which restricts the speed and distance that they can run in pursuit of prey.
 
Katerina Harvati - paleoanthropology, University of Tubingen... 
If you have a wide chest, you should probably have a wide pelvis as well, so your whole body goes as a package, so to speak.

So if you consider that the shape of the chest has to do something with cold adaptation, then shape of the pelvis also is related to that.

Narrator...
Because of their shorter, wider body shapes, running requires Neanderthals to expend up to 30% more energy than their Cro-Magnon counterparts.

John Rennie...
The Cro-Magnons could pretty much literally have run rings around the Neanderthals.

These comments are in line with the preceding notes presented on the contrasting body build and stature between Neanderthals and modern humans, and they speak to the relative edge modern humans would have had over Neanderthals due to these characteristics. Weaponry had already been covered at length; couple that with body plans, and the interplay of that too would have given modern humans a relative edge...well, that's how Clash of the Cavemen relates it:

John Rennie continues...
If it came down to an actual conflict between the Neanderthals and the Cro-Magnons, if the Cro-Magnons could use their greater speed and their advantages with the weapons, they would probably have beaten the Neanderthals handily.

Narrator... 
The Neanderthal spies have tried their best to outrun the Cro-Magnon hunters who spotted them by the riverbank.

But before long, their stocky bodies betrayed them, and they were forced to rest.

Predictably, Clash of The Cavemen makes use of recent northwestern European personalities to portray the Cro-Magnon, but these actors and actresses are obviously more reflective of living populations of Europe which have already attained noticeable physiological adaptations to the region's low UV radiation and cold climes. The so-called Cro-Magnons, which are otherwise a variety of early "anatomically modern" human occupants of Europe, would have had some fairly observable physical differences from recent Europeans. As noted before, they would have less "cold-adapted" body plans than recent Europeans.  This is tacitly inferred from the scatter plots and percentage deviation data of femoral length posted several passages ago.

The oldest more complete specimens of these early 'anatomically modern' humans have yielded ages of a several hundred years over 28ky B.P. The oldest specimen, Oase 1, is a mandible alleged to be that of an 'anatomically modern' human, yielded an approximate age of ca. 40.5 ky B.P. The Gravettian collection, within which the so-called Cro-Magnon specimens were placed, scored brachial and crural index means that were closer to that of the recent sub-Saharan African collection than that of the recent European one.

Being that the Gravettian collection is essentially the pooling of a variety of Upper Paleolithic 'anatomically modern' human specimens, their nearly identical mean limb proportion indices to that of the recent sub-Saharan collection suggests that the number of individual specimens bearing high indexes were dominating enough to attain a high mean; however, this same group of specimens was apparently unable to uphold its number when relative femoral head size and relative bi-iliac breadth were measured. Many Gravettian individuals cluttered near the recent European human RMA slope in both cases. This infers that many more individuals within the Gravettian collection featured relatively "broader" bodies than those in the recent sub-Saharan African collection. When the trunk is relatively wider, this would more than likely be accompanied by wider pelvises. A broad pelvis makes it highly likely that the femoral head size would be large too.

This paradox in estimation of indexes of different areas of the body across the Gravettian collection is perhaps reflective of the availability of individuals which represented modern humans who were on the verge of adapting to the cold environment of Europe. The Gravettian bunch, to recall however, are by no means a homogenous entity. If relatively narrower pelvises and longer appendages of modern humans of Upper Paleolithic Europe would have given them an edge over their Neanderthal counterparts in running distance and speed, then could it be possible that the same plays some as yet-to-be verified part in long-distance runners from Africa, particularly eastern Africa, outperforming their European counterparts?

The possibility should be pondered, given that "broad bodies" and stockier body plans seem to figure more frequently in European samples than in tropical African samples, going by most reports published by European researchers.

To make it easier on the imagination, here are some visual aids on how the average Neanderthal body stacked against that of the modern human counterpart:

Click on the images for higher resolution images

While there are human populations, and individuals, with diminutive stature, the characteristics described above and shown in the above images infer that Neanderthals can and would still standout, because even those aforementioned recent humans still conform to the average human continuum. Some have voiced the concern that bias against Neanderthals have surfaced in how they are portrayed in imagery, and that, they had traditionally been characterized as fairly hairy, stocky & brutish humanoids with ape-like facial qualities.Among advocates of that sort, there is an untested opinion that Neanderthals could easily blend in with recent humans, if they were still around.

While it is true that some bias has seeped into the way Neanderthals had been portrayed in artwork and other imagery, it does not disqualify the fact that there are very real systematic physiological distinctions between Neanderthals and 'anatomically modern' humans and at a sub-species level. The distinctions in body manifestation are not relegated to just stature and body build, but have extended well into cranial morphology [see: The Role of Chin]. On average, Neanderthals are characterized by relatively longer and lower brain-cases in contrast to the shorter and rounder profiles featured on recent human craniums, low slanting foreheads marked by fairly prominent/protruding orbital ridges, prominent and wide noses that are wider than those of most recent human populations, more projecting mid-faces and receding chins, cheek bones that slope backwards in the direction of the brain-case, shorter and outwardly projecting occipital bone, large round eye sockets compared to the somewhat square-like profile of recent humans, comparatively understated or blunted mastoid process among other things; see recap:


Side by Side for better perspective:

Comparison of four views of a modern human skull with a Neanderthal skull cast. Reprinted, with permission, from Kelso, A. J. Physical anthropology. Philadelphia: J. B. Lippincott & Co.; 1970.
 Click on the images for higher resolution

Another recap; data on nasal width of Neanderthals vs. other specimens:

 Click on the image for better resolution.

The nasal width data comes from Robert G. Franciscus, 1999. Note that all comparisons involving recent or modern human samples against the Neanderthal series have reported significant differences.

Now of course, the soft tissues of the face of a living person can and do make a considerable difference in how someone looks, but it is hard to imagine that with all this substantial differences—both post-cranial and cranial—between Neanderthals and modern human isn't going to render a would-be living Neanderthal peculiar in its own right, and him/her standout from recent humans. Heck, humans bicker all the time, and even at times with deadly consequences, about the relatively less acute differences among them, let alone those as considerable as those between modern humans and Neanderthals.

If someone with many of the cranio-facial qualities of Neanderthals were to be in the midst of recent humans, then chances are that said person may be labeled by others silently or aloud, if not bullied outright by some, as being a "Neanderthal", or perhaps an "ape", "primitive" or some other colorful names analogous to those characterizations. People kill and mock others on something as trivial as skin color differences alone, let alone morphological differences.

Attention has even been called in some quarters, to the somewhat prominent orbital ridges common among Australian aboriginals, and usually in an unflattering manner, as if to imply that said aboriginals are somehow inferior to those begging said attention. It occurs not to these self-aggrandizing characters, that such a robust feature in a living human group like the Australian aboriginals of course, has nothing to do with "primitiveness" or biological inferiority of any degree; it could well have been a product of selective pressure, if not as yet-to-be-determined stresses brought to bear on the cranium due to subsistence or social activities and/or environmental pressures. Prominent orbital ridges also have noticeable incidences among recent Europeans, although perhaps not to the extent found in Australian aboriginals.

On a possibly lighter note, some have tried their hand in imagining how a living Neanderthal would look like through computer generated visualization; from around the web, we have for example, one featuring a Neanderthal in a suit, and others in other contemporary attires:

Click on all images for higher resolution.

These renditions, where facial characteristics are concerned, do not invoke traditional stereotypes of the Neanderthal as the rough ape-like caricature; if anything, a case can be made that artists here may have even attempted to make their Neanderthal characters as recent-human looking as they possibly can. The image on the far left does not apply the ape-like prognathism to the character that is seen in other Neanderthal renditions; none of the three images do, for that matter. In the middle image, the nose size of the character is not even out of line with those characteristic of recent humans. One might recall that pretty much ALL the recent human cranial series had relatively modest mean nasal aperture widths when compared against that of Neanderthal series, notwithstanding variations between and within the recent humans samples themselves. The picture on the far right too does not feature a nose that couldn't easily be associated with recent humans. The far right renditions features the most prominent nose that one can more readily identify with that invoked by Neanderthal crania.

All three images feature personalities with mildly projecting mid-faces, although the image on the far left more closely approximates the profiles scene of actual Neanderthal remains than the other two. It may even be so subtle in the far right rendition that one might not notice the facial projection, if not closely inspected. Still, only so much can be done by the artist to make a Neanderthal character as recent human as possible; for instance, all three renditions could not ignore the relatively long anterior or side profile of the Neanderthal or the prominent orbital ridges. The sloping forehead is figured into in all three renditions, but the far right image appears to make this more apparent of all the renditions, perhaps to be followed by the far right rendition.

While the prominent orbital ridge may be more obvious, it isn't necessarily all that apparent that the forehead is slanted to any considerable degree, as seen on actual Neanderthal remains, perhaps in no small part due to the somewhat high-looking forehead. It is hard to determine the brain-case profile of the skull on the far right and middle renditions, but the far right rendition does invoke the low and rather flatter head profile of Neanderthals; if anything, the profile recalls that of the rounder profile of recent humans. The far right rendition once again, provides a more obvious feel to a receding chin, reminiscent of Neanderthal crania, than the other two renditions.

Now, a peek into a growing trend in the way Neanderthals are rendered in imagery, whether it is on an artist's canvas or computer/TV monitors:

Starting with a collection of renditions—both old and relatively recent—that seem to convey the Neanderthal in a more traditional stereotype of a considerably hairy, though exhibiting a stocky, broad and robust post-cranial body plan, rugged personality with a face that leans noticeably towards an ape-like appearance:

Click on the images to enlarge.

Some of these renditions do not look all that considerably different from those which convey the evolutionary predecessors of Neanderthals and modern humans, namely the Homo rudolfensis, Homo habilis, Homo ergaster, or Homo erectus; see:

Click on the images for higher resolution. Image captions: reconstructions or renditions of Homo rudolfensis, Homo habilis, Homo ergaster, and Homo erectus.

Perhaps of all the examples of the Neanderthal renditions presented right above the last set of images on human predecessors, the last rendition is probably the somewhat more gracious, whereby the prognathism is less pronounced, while body hair is noticeably miniscule. Contrast those renditions to the following, perhaps signaling a growing trend in applying a relatively more gracious approach to personifying the Neanderthal:

Click on all images for hi res.

The above feature both old and relatively more recent renderings. Not all old renderings necessarily adhered to the more traditional stereotypical caricatures. Perhaps the far left image on the top exemplifies this. That image features a Neanderthal bust in the middle, flanked by Java man (aka Pithecanthropus) and the so-called Cro-Maganon busts on either side. The busts were reportedly created for the American Museum of Natural History around 1915, by J. H. McGregor of Columbia University.

While there was certainly widespread academic prejudice thinking about Neanderthal's behavioral capacities and physical attributes at the time, the bust here seems to have been more inspired by the actual morphological patterns of Neanderthal specimen used as the basis than influenced by any presumptive perception of the species. Note that the mouth is not characterized by the level of [ape-like] prognathism applied on other occasions, and perhaps the forehead profile is not as low and slanted as seen in some other renderings.

Still, the busts were used to uphold the prevailing social views of the day, which were heavily driven by racialist ideology and reaction. Word is that, the busts were used not only "to impress visitors with the wonders of science, but also to promote the eugenic theories of the museum’s director, Henry Fairfield Osborn. The images were reproduced in many biology textbooks to support a narrative of racial progress. Pen-wielding students often “repurposed” them to illustrate their own stories."

In a good number of renderings posted above, Neanderthal characterizations even come close to strongly resembling recent humans, whereby in some instances, one would be challenged to point out the cranio-facial differences between the two, that consistently come to the surface in osteological examinations. The female child, the adult female, and the personalities in the last two images, are not much different from living occupants of Europe, and may even be lost in a European crowd of recent humans! The relatively flat and high foreheads, skin, eye and hair pigmentation, mild nose width/size and mild mid-facial protrusion in some instances may have something to do with this.

Of all the bunch above, the personality with a pony-tail and the one accompanying the adult female appear to be more forthright about the low forehead profile in accompaniment by high-situated orbital ridges, and perhaps, the mid-facial protrusion. Still, these renderings do not go so far as to convey the ape-like appearance seen in other renderings [examples posted above]. Below, is a side by side comparison between an early rendering of the Neanderthal, and a more recent one:


The image on the left is reportedly a rendering from the Chicago Field Museum dating to 1920. Noticeably absent here, is the ape-like facial profile that is typical of other renderings in that era and following time frames. Once again, the artist seems to be more influenced by the bone structure of the cranium than a priori typecasting. This is supported by the attention to conveying the receding chin, low and sloping forehead accommodated by prominent orbital ridges, while the nose figures fairly prominently on a mid-face that projects outwardly, but NOT in association with a mouth that is characterized by prognathism, as seen in some of the renderings posted earlier.

Also absent, is the heavy body hair attribute seen in other renderings; perhaps the artists intention is to just focus on the fundamental profile, and so, do away with anything that might obscure this, like scalp hair or body hair. The neck profile might be the attribute of this rending that is likely to raise the most questions by potential critiques. Neanderthals were fairly stocky with broad bodies; a good chance is that their necks were also short and bulky, although in this rendering, the neck is bulky enough that it obscures the occipital protuberance that is characteristic of cranial remains. Contrast that to the one in the image on the right.

In the image on the right, the personality's occipital protuberance is more visible, but not as prominent as those seen on cranial remains. The character in said image has an occipital bone profile that is more in line with those of recent humans; Neanderthals typically have occipital buns, which is rare in recent humans. While the frontal bone is low and slanted/flat, the overall profile of the neuro-cranium is more rounded than the sort generally featured on Neanderthal skulls.

Still on the subject of the image on the right: The neck is still short, but not as bulky as that seen in the black and white image on the left. The anterior view gives only subtle indication of it, if any at all, but the side profile gives the observer a better perspective into the mid-face profile. Accordingly, the mid-face noticeably protrudes outward, but like the image on the left, there is no protrusion (prognathism) of the mouth region here.

The chin is not prominent, but it does not recede as far as that in the image on the left either. Many images of Neanderthal skull suggest that the chin featured in the left image best approximates the average Neanderthal profile. The nasion of the character in the right image is relatively shallower than that of the character in the left image; again, the nasion of character in the left image best approximates those seen on Neanderthal cranial profiles. Additionally, said character's nose is not actually as prominent as that on the character in the black & white image; it only projects outward primarily because of the protrusion of the mid-face. The nose long and slender, when data points to a typically wide prominent nose profile for Neanderthals.

Perhaps the artist of this reconstruction [right image] was compelled to follow the protruding mid-facial profile of the Neanderthal specimen, and other features, like the low and nearly flat forehead, because if one takes those away, little else about the cranium will resemble a typical Neanderthal profile, but if one looks at especially the anterior view of the reconstruction/bust, it seems that the artist was attempting to give his Neanderthal subject a recent human feel to it as much as possible. There is clearly a movement towards casting Neanderthals in a more human light.

Click here for the next segment of this topic: So What's the Deal with the Neanderthal, Their Demise? - 3

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Neanderthal in the News:

Neanderthal Cloning Project


1 comment:

Pearlman CTA said...

As Richard Rasberry pointed out Neanderthal lived longer, 2X+-.
That is consistent with the recent complex creation (RCCF) framework for understanding science in full context.
Two of the considerations: Neanderthal fossils we have are from post, not pre Mabul year which was 4117 years ago. Pre Mabul we live 9 times longer on average, how do we know post Mabul?, Neanderthal fossils are found /associated with caves formed by the Mabul. See RCCF for references.
So Neanderthal (as did Og or Ogs DNA) one way or the other DNA survived with one or more of the 3 younger couples on the Ark.
So no need for African and Neanderthal DNA mixing.
As per the RCCF the radiation build/Oxygen decline that started with the Mabul was gradual before leveling off. So those born toward the last third of the ice age (Years 1657-1996), as was Abraham born 1948 AM (after Adam formed in full stature start of year one ) should have lived 175 +- years based on the life span of Abraham. So 2X longer life span on average than modern man for those born during later ice age about right.
Reference RCCF