For many people the new year represents an occasion to set the clock back to zero and have a fresh start. We invariably eat too much during the festive season, only later to feel remorse for our gluttonous ways. With another new year comes the renewed goal of losing some of the recently acquired extra padding. There are no end of miraculous sounding diets which promise to convert fat to flat. Among the various in vogue diets is the Paleo diet (short for Paleolithic diet), also known as the caveman diet. The central premise behind the Paleo diet is that many human adaptations evolved during the Palaeolithic, and as such, we are maladapted to the modern world in which we find ourselves.

The premises of the Paleo diet raise some interesting questions that are well worth exploring. For instance, are we really better adapted to the Palaeolithic than the modern era and which aspects of the Palaeolithic does the Paleo diet reference? Many proponents ask the question “who ever heard of a fat caveman?”, as if the answer is somehow inferred. While it is seems be the case that the average Palaeolithic human had a brawnier body than the average modern human, we should not confuse correlation with causation. A better question to ask is whether the “caveman” physique is due solely to diet or are there other factors at play? Read More...

Tags: palaeolithic, diet, paleo diet, palaeo diet

Mathew John Wedel (right) is a palaeontologist who specialises in sauropod dinosaurs. Recently, he was invited to be a talking head for Discovery Channel’s new series, Clash of the Dinosaurs. In the making of such shows, experts are often interviewed for hours on end about a variety of topics, which is later edited down to little more than a pithy one-liner. Sound bites are anathema to the complexity of science. Scientists often feel hard done by, after spending hours doing to their best to explain the science, to see it condensed down to a few words.

However, what happened Matt is much more disturbing. It has been long known that sauropods have a swelling in the sacral region, leading some people to suggest that it may have functioned as a second brain. This idea has been thoroughly debunked. When Matt was asked to comment on this here is how the original unedited conversation went down:

”Ok one of the curious things about sauropods is that they did have a swelling in the spinal cord in the neighbourhood of their pelvis. And for a while it was thought that may be this was sort of like a second brain to help control the back half of the body. Erm there are a couple of misconceptions there. One is that most animals control large part of their body with their spinal cord. If you’re going through day to day operations like just walking down the street and your minds on something else your brain isn’t even involved in very much controlling your body. A lot of that is a reflex arc that’s controlled by your spinal cord. So it’s not just dinosaurs that are controlling their body with their spinal cord, it’s all animals. Now the other thing about this swelling at the base of the tail is we find the same thing in birds and its called the glycogen body. It’s a big swelling in the spinal cord that has glycogen which is this very energy rich compound that animals use to store energy. Problem is we don’t even know what birds are doing with their glycogen bodies. Er the function is mysterious – we don’t know if the glycogen is supporting their nervous system – if its there to be mobilised, help drive their hind limbs or the back half of their body and until we find out what birds are doing with theirs we have very little hope of knowing what dinosaurs were doing with their glycogen bodies.”

I can only imagine the shock Matt experienced when this got edited down to:

“This was sort of like a second brain to help control the back half of the body.”

This is not what he said at all. In fact, he said the exact opposite, even going so far as to give the reasons why this is a discredited theory. Not only is this downright dishonest on the part of the producers, it also calls into question the credibility of this professional scientist. More generally, it gives legitimacy to the ‘second brain’ hypothesis in the eyes of the public. Understandably, enraged by what he saw, Matt sent an email form Dangerous Ltd, the production company who were responsible for filming the documentary. He received a reply that amounted to a nopology, even having the audacity to say: “we were simply working on the show ever aware of the demands of our audience.” And what about presenting the facts or fairly representing the views of the scientists? Read More...

Tags: media, fail, palaeontology, science

This abstract from a 1961 paper made me smile:

Living Cork-Kerry Irish were compared with 139 modern and ancient peoples using 36 factors, 14 blood groups, 3 skin, hair and eye pigmentations and 22 physical measurements. The method was a form of multiple correlation in which the class interval for each factor was one-half the standard deviation, and numerical values allocated to each half-standard deviation. The Irish, Northern Scots, Icelanders, S.W. Norse, N. Dutch and Frisians form a racial entity with 97 per cent. inter-correlation and very little change during the past 1,000–4,000 years. There is a high correlation with the ancient Scythians substantiating the Irish legends of descent from the kings of Scythia. There is a substantial mixture of upper palaeolithic and Neanderthal man in the north-western perimeter of Europe, exemplified by the people of Cork and Kerry, a mixture not shared by the American Indians, the Australian Aborigines, and by the Bushmen and Pygmies of Africa. There is a good possibility that the large frame, red hair, blue eyes and white skin of West Europe was contributed by upper palaeolithic and Neanderthal men.

Casey AE, Franklin RB. 1961. Cork-kerry Irish compared anthropometrically with 139 modern and ancient peoples. Irish Journal of Medical Science. 36 (9).

Tags: Neandertals, Irish

Chinese scientists say that a recently discovered partial jaw from Guangxi challenges the ‘out of Africa’ model of modern human origins, while lending support to the multiregional hypothesis. The 110,000 year-old mandible is described as having a chin that juts “ever so slightly outward.” These scientists assert that the presence of chin shows that there was significant gene flow between populations of modern Homo sapiens and archaic Homo.

Wu Xinzhi of the Chinese Academy of Sciences had the following to say about the find:

”The finding was strong evidence to prove the multiregional model, and from this evidence, it was significant to solve the academic dispute between 'the multiregional mode' and 'out of Africa theory’”.

It is interesting to note Xinzhi’s use of the past simple tense to suggest that this is a closed case. Far from it! Palaeoanthropological theory has moved on from the multiregional sensu stricto versus ‘out of Africa’ sensu stricto dichotomy that predominated the discussion during the latter half of the last century. Nevertheless, the question of how much gene flow, if any, took place between modern and archaic Homo is still very much a debated issue. Read More...

Tags: Out of Africa, Multiregional, China, chin

One of the most visually striking differences between modern humans and other hominins is the shape of the forehead. The frontal bone of the forehead serves two primary functions: it houses the frontal lobes of the brain in the anterior cranial fossa and also forms the orbital roof. When the orbits are positioned anterior to the frontal lobes, a supraorbital torus or brow ridge, forms in order to bridge the gap. This is particularly the case in archaic members of the genus Homo, whose brain cases are positioned well behind their faces.

The incredible brow ridges of Homo erectus is perhaps this species most salient physical feature. They possess a flattened forehead with a bar-like brow ridge over the eye sockets. The supraorbital torus is continuous and thickened laterally, which in turn is associated with a pinching of the orbital breadth behind the eye sockets, known as postorbital constriction. In H. erectus, the supraorbital torus is separated from the frontal squama by a depression called the posttoral sulcus. While most Erectines conform to this general bauplan, there is a lot of regional variation in the exact form of the torus.

Neandertals are characterised by their long, large, low and wide skull. They have a double-arched browridge above the orbits, which angles backward on the sides of the face. It is depressed along the middle by the presence of a supraglabellar fossa. Compared to H. erectus, Neandertals have a more vertical and rounded forehead, with a less pronounced supraorbital torus. Read More...

Tags: supraorbital torus, brow ridge, frontal bone

Ever since William King proposed the taxonomic designation Homo neanderthalensis in 1864, there has been intense debate as to whether Neandertals represent a distinct species from us. Species, as defined by the biological species concept, are populations of organisms that can potentially interbreed and have fertile offspring. It is believed that the lineage leading to Neandertals and modern humans split sometime around 500,000 years ago. For most of their existence Neandertals and early modern humans were geographically isolated (and by extension reproductively isolated) from one another. The big question is whether they could have produced viable offspring when they met.

Today, most researchers acknowledge that some sexual encounters could have occurred between Neandertals and modern humans. The more interesting question is how common were these encounters and did they leave their mark on the modern gene pool. Undoubtedly, modern humans and Neandertals would have recognised each other as fellow humans but this does not mean that they would have acted humanely to each another. Countless social and psychological studies have shown humans to have a very strong "us versus them" mentality, that no doubt also existed in our ancestors. It is unlikely that modern humans and Neandertals had an easy relationship. Most sexual encounters that took place between the two were likely opportunistic and probably involved enslavement and rape. Read More...

Tags: Neandertals, modern humans

Razib Khan of the Gene Expression blog interviews John Hawks regarding the significance of Ardipithecus ramidus.

Tags: John Hawks, interview, video

Michael Balter reports for Science on a recent conference held in Gibraltar entitled Human Evolution 150 Years After Darwin [1]. Gibraltar holds a special place in palaeoanthropologists' hearts. Not only is it the place where the first Neandertal were discovered in 1848, it is also seems to have been among the last refugia of this species, prior to their disappearance some 30,000 years ago. Charles Darwin got to see the original Gibraltar specimen in 1864, which perhaps influenced him to comment on the "well developed and capacious" braincase of Neandertals in The Descent of Man [2].

At the conference, much attention was focused on the Middle Pleistocene "muddle in the middle" [3], particularly the role of Homo heidelbergensis in hominin evolution. While H. heidelbergensis possesses both archaic and derived traits intermediate between H. erectus and later members of the Homo genus, it lacks uniquely derived traits or autapomorphies, which are a prerequisite for defining a species.

H. heidelbergensis has traits that have been interpreted as nascent Neandertal autapomorphies, leading some researchers to propose that there was a continuous evolution of Neandertals [4-6]. This accretion model would make H. heidelbergensis a chronospecies on the continuum of the Neandertal lineage, a view championed by Jean-Jacques Hublin. The accretion model proposes that Neandertals evolved by anagenesis, i.e. non-branching evolutionary change. Read More...

Tags: Homo heidelbergensis, Middle Pleistocene, Atapuerca, Neandertals

One of the anatomical features that sets humans apart from other living primates is the shape of our pelvis. The shift from a quadrupedal aboreal lifestyle to habitually walking on two legs requires a substantial reconfiguration of the hip region. The 4.4 million year old Ardipithecus ramidus fossil remains give us a glimpse of what the one of the earliest members of the hominin lineage looked like. While the feet of Ar. ramidus show that it was still adapted to life in the trees, the pelvis shows significant adaptations to walking upright on two legs.

The gluteus maximus, which is a relatively minor muscle in quadrupeds has been reconfigured into the largest muscle in humans, in order to stabilize the pelvis and trunk in an upright position. The derived nature of the ilium of Ar. ramidus suggests that the enlargement of the gluteal maximus had already begun. The craniocaudal height of the pelvis is also reduced, which would have lowered the relatively long trunk's centre of mass. This would have allowed for more stable bipedal locomotion. Read More...

Tags: Ardipithecus ramidus

Welcome to Four Stone Hearth number 75. Four Stone Hearth is a fortnightly anthropology blog carnival. Topics covered span the four major fields of anthropology: archaeology, socio-cultural anthropology, bio-physical anthropology and linguistic anthropology. If you would like to host the carnival, please write to Martin Rundkvist. The next issue will be hosted at the Afarensis blog on 23 September. So without further preamble, let's get on with the show.

Archaeology
Martin Rundkvist talks about his experience digging at a Middle Neolithic coastal site in Sweden. Among the finds were small potsherds and a fine example of Pitted Ware.

A recent article in the journal Nature reports on the "oldest handaxes" in Europe. John Hawks gives his interpretation regarding the significance of these bifaces, suggesting that although Lower Pleistocene hominins had the technology to produce bifacial handaxes, they were not a necessity. Read More...

Tags: four stone hearth

A recent article in Scientific American has generated a lot of buzz in the anthropology blogosphere. The piece discusses the problems of accessing human fossil remains, reopening the discussion on how open anthropology needs to be. The reason why data acquisition is such a problem in palaeoanthropology is captured in the opening sentence of an article Stephen Jay Gould and David Pilbeam wrote for Science:

"Human paleontology shares a peculiar trait with such disparate subjects as theology and extraterrestrial biology: it contains more practioners than objects for study."


– Stephan J. Gould and David Pilbeam

Whenever supply cannot keep up with demand, you can be sure that problems will follow. (Many parents have learned this to their chagrin, when they find out that the Christmas toy du jour, their beloved child so wanted, is sold out.) Each newly unearthed fragment of human bone represents yet another valuable piece in the ever-growing jigsaw puzzle that is our evolutionary history. The study of primary data is of prime importance in paleoanthropology. As a result, a conflict arises, due to the need to study fossils and the limited access placed upon them. Restricted access occurs for a number of reasons, ranging from valid concerns over the fragility of a particular specimen, to scientists reaping the benefits of a research monopoly.

There is an unwritten rule in palaeoanthropology that the discoverers of a fossil have the exclusive rights to publish the initial monograph describing their specimen. Palaeoarchaeologists invest a lot of resources, time and effort in recovering fossils. They will often literally risk body and limb. Dehydration, food poisoning, snake bites, diseases and infections are but some of the hazards field archaeologists face. When they are not digging they are often engaged in the uneviable task of writing grants for their projects. It is understandable that they are wary of outsiders who expect free access to their hard-won prizes.

Read More...

The 74th Four Stone Hearth anthropology blog carnival is available over at Adam Henne’s Natures/Cultures blog. Catch up on the latest on anthropology blogging. The next Four Stone Hearth will be hosted here on the 9th of September. Send any anthropology submission for the upcoming carnival to Martin Rundkvist or me (be sure to replace [AT] with @ in the email addresses).

Tags: four stone hearth