tag:blogger.com,1999:blog-29019195455849814662010-10-21T04:31:22.161-07:00Ad HomininCiaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.comBlogger39125tag:blogger.com,1999:blog-2901919545584981466.post-97579697072339142010-10-15T18:16:00.000-07:002010-10-15T18:16:22.537-07:00Are cancers a modern phenomenon?Yesterday, I came across a <a href="https://www.dailymail.co.uk/sciencetech/article-1320507/Cancer-purely-man-say-scientists-finding-trace-disease-Egyptian-mummies.html<br />" rel="external">news report</a> on a study by Professor Rosalie David and Professor Michael Zimmerman of the <a href="https://www.manchester.ac.uk/aboutus/news/display/?id=6243" rel="self">University of Manchester</a>, who postulate that cancers are in large part a modern phenomenon and are 'man-made'. I have objections to almost all of the claims the researchers make, so I will address them one by one.<br /><strong><em><ul>Tumours were rare until recent times when pollution and poor diet became issues, the review of mummies, fossils and classical literature found. </ul></em></strong><br />It is true that there are more contaminants in the environment and poor lifestyle choices has led to an increase in some types of cancers. Numerous studies have shown pollution to be a factor in cancer, albeit a minor one. Inactivity, excess body fat, heavy drinking, and smoking are well known to increase your risk of developing cancer. <br /><br />However, the main reason for the rarity of cancer in the past is that people lived much shorter lives. The chances of development many forms of cancer increases with age. Improvements in healthcare mean we are living much longer than past generations. Most cancers occur in individuals over the age of 50, well beyond the expected lifespan for much of human history. The increased detection of cancer is also due to our improved capacity to diagnose cancers. <br /><strong><em><ul>'The virtual absence of malignancies in mummies must be interpreted as indicating their rarity in antiquity, indicating that cancer-causing factors are limited to societies affected by modern industrialisation.' </ul></em></strong><br />All animals get cancer. Even <a href="https://scienceblogs.com/observations/2010/09/ocean_of_pseudoscience_sharks.php" rel="external">sharks</a>! There is no reason to think that our ancestors were any different.<br /><br />The authors find that there is a low prevalence of cancers which are already rare for the age group under examination. In a different study, Zink and colleagues observed 4 cases of malignant tumours in a series of 325 Egyptian mummies. It is reasonable to assume that these numbers represent a minimum, given the limitations of diagnosing cancer in ancient tissues.<br /><br />These and other studies show that cancers did occur in Egyptian mummies. How then do the authors get from cancers occurred in ancient populations to cancers are the product of modern industrialisation?<br /><strong><em><ul>Dismissing the argument that the ancient Egyptians didn't live long enough to develop cancer, the researchers pointed out that other age-related disease such as hardening of the arteries and brittle bones died [sic] occur. </ul></em></strong><br />The authors of this study conveniently choose to dismiss perhaps the most important predictor of most cancers – age. The study looked at mummies between the ages of 25 and 50, although people over the age of 50 are by far at greatest risk of getting cancer. According to a 2010 <a href="https://www.cancer.org/acs/groups/content/@epidemiologysurveilance/documents/document/acspc-026238.pdf" rel="self">American Cancer Association report [pdf]</a> around 78% of cancers are diagnosed in people 55 years and older. A primary reason many cancers are on the increase is because people are living longer. Given the short lifespan of prehistoric people it is inevitable that the occurrence of cancers will be much greater today.<br /><strong><em><ul>Even the study of thousands of Neanderthal bones has provided only one example of a possible cancer. </ul></em></strong><br />The one example the authors refer to is the Stetten II skull bone, believed to date to 35,000 years BP (before present). There a tumour on the parietal bone of this specimen. However, much of the Stetten material has been redated to less than 5000 years BP, including a cranium designated Stetten II.<br /><br />What's more, the authors fail to mention the Ferrassie Neandertal, whose leg bone lesions have been interpreted as possibly being the result of lung cancer. This specimen has bilateral periostitis, which is a common manifestation of hypertrophic pulmonary osteoarthropathy (HPO). HPO is a condition associated with a number of circulatory and lung diseases. Among the most common causes of HPO are pulmonary carcinomas. Palaeopathology is a tricky business in which practitioners attempt to reconstruct past diseases and infections from often ambiguous marks left on the bones. While the Ferrassie case is open to interpretation, it should not be dismissed out of hand.<br /><br />It is also worth noting that the incidence of bone cancers are incredibly low. Moreover, osteosarcomas affect mostly children. Bone cancers are among the rarest types of cancer. The number of new cases of bone cancer in the US so far this year is 2,650. To put this into perspective that's 0.000009% of the US population that have been diagnosed with bone cancer in the last year. Other cancers may secondarily affect bony tissue but, like the Ferrassie Neandertal above, the aetiology in such cases is more equivocal.<br /><strong><em><ul>'There is nothing in the natural environment that can cause cancer. So it has to be a man-made disease, down to pollution and changes to our diet and lifestyle. </ul></em></strong><br />The ascertain that nothing in the environment causes cancer is demonstrably wrong. Prolonged exposure to UV rays is the chief cause of skin cancers. Human papillomaviruses and hepatitis viruses cause cervical and liver cancers respectively. Helicobacter pylori bacteria have been linked to gastric cancer. Exposure to radon is the second leading cause of lung cancer (after smoking), while carcinogenic aflatoxins are made naturally by moulds.<br /><br />In conclusion, the researchers found only a few cases of cancer in a relatively small sample of mummies. These mummies were all estimated to be 50 years of age or younger – a demographic with a relatively low risk of cancer. Added to this, it is likely that the true rate of cancer was much higher than what was possible to diagnose for these ancient and somewhat degraded specimens. While it is interesting to ask how prevalent cancers were in the past, this study does little to shed light on the answer.<br /><br /><br /><strong>References</strong><br /><br />Fennell and Trinkaus (1997). Bilateral femoral and tibial periostitis in the La Ferrassie 1 Neanderthal. Journal of Archaeological Science. 24 (11) pp. 985-995.<br /><br />Rosalie David and Zimmerman (2010). Cancer: an old disease, a new disease or something in between? Nature Reviews Cancer 10, 728-733.<br /><br />Zink, Rohrbach, Szeimies, Hagedor, Haas, Weyss, Bachmeier and Nerlich (1999). Malignant tumors in an ancient Egyptian population. Anticancer research. 19 (5B):4273-7.<br /><span style="color:#FF0000;"><!-- AddThis Button BEGIN --><br /><body><script type="text/javascript">var addthis_pub="4a1c2d6a388b86af";</script><br /></span><span style="color:#FF0000;"><a href="https://www.addthis.com/bookmark.php?v=20" onmouseover="return addthis_open(this, '', '[URL]', '[TITLE]')" onmouseout="addthis_close()" onclick="return addthis_sendto()"><img src="https://s7.addthis.com/static/btn/lg-share-en.gif" width="125" height="16" alt="Bookmark and Share" style="border:0"/></a><script type="text/javascript" src="https://s7.addthis.com/js/200/addthis_widget.js"></script><!-- AddThis Button END --></body></span><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-9757969707233914?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0tag:blogger.com,1999:blog-2901919545584981466.post-4338318010304721002010-08-18T14:42:00.000-07:002010-08-18T14:58:20.049-07:00Australopithecus habilis!<div class="image-left"><img class="imageStyle" alt="12tool1_ready-articleLarge" src="/files/12tool1_ready-articlelarge.jpg" width="480" height="239"/></div>The oldest known human tool technology is known as <a href="https://en.wikipedia.org/wiki/Oldowan" rel="external">Oldowan</a>. These tools were originally thought to have been the handiwork of an early member of our genus, <em>Homo</em>. In fact, Louis Leakey and colleagues named the species <em>Homo habilis</em> (literally "handy man") because of its association with Oldowan stone tools. There is an almost doubling in brain volume and expansion of the frontal lobes in habilines compared to their <a href="https://en.wikipedia.org/wiki/Australopithecus" rel="external">australopithecine</a> antecedents, which some have attributed to the formers use of stone tools.<br /><br />Stone tools found during excavations in the early 1990s in the Afar region of Ethiopia have been dated to between 2.5 and 2.6 million years. However, <em>H. habilis</em> does not first appear on the scene until around 2.3 million years ago, which would make australopithecines or <a href="https://en.wikipedia.org/wiki/Paranthropus" rel="external">paranthropines</a> the most likely authors of this assemblage. Even these earliest stone tools have been deemed too advanced for our first foray into stone tool making and many researchers predicted that even earlier tools were awaiting discovery.<br /><br />Researchers working in the Dikika region of Ethiopia have recently uncovered bones dating to between 3.2 and 3.4 million years ago that show all the hallmarks of butchering. The cut marks and percussion marks are suggestive of defleshing and the removal of bone marrow. From a behavioural aspect, it is unclear whether this represents hunting or the scavenging of recently dead animals.<br /><br />Bone trauma can be an incredible tricky thing to interpret. Trampling, tooth marks from scavenging, direct contact with rocks, among other agents can leave pseudo-cut marks on a bone. The bones were analysed under scanning electron microscope, with the researchers concluding that stone tools were most likely responsible for the cut marks and fracture patterns.<br /><br /><em>Australopithecus afarensis</em> is the only known hominin to date from this time period and is, for the time being, the best candidate for making these marks. Tool use is seen in both our <a href="https://www.youtube.com/watch?v=xRN-fHdGzUY" rel="external">ape</a> and <a href="https://www.youtube.com/watch?v=q2CbBSu8X6Q" rel="external">monkey cousins</a> and it seems likely that <em>A. afarensis</em> also utilised tools. Researchers have shown that <em>A. afarensis</em> would have been capable of the manual dexterity needed to manipulate tools. What is less clear is whether these cut marks were made by stone tools specifically fashioned for butchering or whether these hominins used sharp-edged natural stones. Whether these were fabricated or natural they were still used as tools. However, the dentition of <em>A. afarensis</em> suggests that meat constituted a negligible part of their diet. The large molars and thick enamel of this hominin point to a diet rich in tubers and other vegetation.<br /><br />The elephant in the room is the absence of any tools at the Dikka site. This is unusual since tools, which ordinarily preserve better, typically outnumber bones at butchering sites. It is also unclear how many bones were collected at the site and why none of these show tool marks. Indeed, the entire evidence consists of only two small fragments of fossilised bone. The authors suggest that the lack of additional bones with cut marks could indicate that the bones were processed off-site, where better quality tools were available. <br /><br />The evidence is tantalising but more is needed. Hopefully, further excavations at Dikka will uncover the missing stone tools and the humans who made them.<br /><br /><strong>References</strong><br />Alba DM, Moyà-Solà S, Köhler M. 2003. Morphological affinities of the Australopithecus afarensis hand on the basis of manual proportions and relative thumb length. Journal of Human Evolution 44: 225–254.<br /><br />McPherron SP, Alemseged Z, Marean CW, Wynn JG, Reed D, Geraads D, Bobe R, Bearat HA. 2010. Evidence for stone-tool-assisted consumption of animal tissues before 3.39 million years ago at Dikka, Ethiopia. Nature 466:857-860.<br /><br />Semaw, S., Renne, P., Harris, J.W.K., Feibel, C., Bernor, R., Fesseha, N. and Mowbray, K. 1997. 2. 5 million-year-old Stone tools from Gona, Ethiopia. Nature, 385:333-338.<br /><span style="color:#FF0000;"><!-- AddThis Button BEGIN --><br /><body><script type="text/javascript">var addthis_pub="4a1c2d6a388b86af";</script><br /></span><span style="color:#FF0000;"><a href="https://www.addthis.com/bookmark.php?v=20" onmouseover="return addthis_open(this, '', '[URL]', '[TITLE]')" onmouseout="addthis_close()" onclick="return addthis_sendto()"><img src="https://s7.addthis.com/static/btn/lg-share-en.gif" width="125" height="16" alt="Bookmark and Share" style="border:0"/></a><script type="text/javascript" src="https://s7.addthis.com/js/200/addthis_widget.js"></script><!-- AddThis Button END --></body></span><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-433831801030472100?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0tag:blogger.com,1999:blog-2901919545584981466.post-83414131088007721872010-04-15T13:29:00.000-07:002010-04-15T14:17:47.583-07:00Australopithecus sediba: an evolutionary mosaic<img class="imageStyle" alt="Science 2010 Balter-2" src="/files/science-2010-balter-2.jpg" width="480" height="311"/><br /><strong><em>The skull of MH1, a juvenile member of the species Australopithecus sediba.</em></strong><em><br /></em><br />Two beautifully preserved partial skeletons of a new species of human are described in the current issue of <em>Science</em> magazine. The new species has been given the taxonomic name <em>Australopithecus sediba</em>. The remains were discovered in Malapa, South Africa, located a mere 15km from the famous Sterkfontein caves. The site preservation is incredible, especially considering its great antiquity. The specimens themselves are relatively free from distortion and show few signs of taphonomic modification. <br /><br />The fossils are around 2 million years old based on a combination of radiometric and palaeomagnetic dating, as well as the associated animal remains found at the site. The skeletal remains are those of an adult female and a boy of between 9 and 13 years. <em>A. sediba </em>would have stood at about 1.3 metres tall and had relatively long arms like those seen in other australopithecines.<br /><br />Palaeoanthropologists are split on whether these fossils are members of our genus, <em>Homo</em>, or the earlier <em>Australopithecus</em>. The boy's brain, which is estimated to be around 95% its projected adult size is only 420 cc, some 90 cc below the smallest brain known for early <em>Homo</em> (with a brain case of only 510 cc, KNM-ER 1813 itself is considerably smaller than other Homo specimens). It is on a par with the cranial capacity of the diminutive species <em>Homo floresiensis</em>.<br /><br />The Malapa hominins have a mix of both australopithecine and <em>Homo </em>traits, with the authors of the paper suggesting greatest specific affinities to <em>A. africanus</em>. The small body, long arms and small brain case are indeed more suggestive of australopithecines. <em>A. africanus</em>, itself is a very variable species and it would not be absurd to suggest that the Malapa hominins represent one tail of the bell curve of variation within that species. The biggest difference between the Malapa hominins and <em>A. africanus</em> is the small dental dimensions of the former. Other traits are more typically associated with <em>Homo</em>, such as long legs, short hands, a derived pelvic configuration, gracile jaw with a weakly developed chin, small teeth, a flat face and a projecting nose. This mosaic anatomy should be a warning to palaeoanthropologists wishing to identify species based on a single anatomical feature.<br /><br />It has been suggested that <em>A. sediba</em> could be a candidate ancestor for <em>Homo,</em> based on the number of derived traits it share with early representatives of that genus (more than any other known australopithecine). While the site is too late to be ancestral to <em>Homo</em>, the species may not be.<br /><br />So should <em>sediba</em> be classified in the genus <em>Australopithecus</em> or <em>Homo</em>? The traditional way of distinguishing <em>Australopithecus</em> from <em>Homo</em> was the larger brain size of the latter (with a cutoff point of around 600 cc) and its use of stone tools. Using of a trait like brain size is highly problematic, since it is strongly correlated with body size and there is not a one-to-one correspondence between brain size and brain function. The recent discovery of <em>H. floresiensis</em>, with its small but derived brain, was found together with sophisticated stone tools. Similarly, a preliminary analysis of <em>A. sediba</em> suggests that its brain is more derived than its size would suggest. The first unambiguous appearance of stone tools in the palaeoanthropological record are attributed to <em>H. habilis</em>. Stone tools have not been recovered from Malapa but formal excavations have yet to get underway there. If stone tools are recovered it will require a rethinking about how we define our genus. While brain size is not the only distinguishing characteristic palaeoanthropologists use to separate <em>Homo </em>and <em>Australopithecus</em>, the dividing line is nonetheless an arbitrary one. For the moment, I think <em>Australopithecus</em> is a reasonable preliminary designation for this material, particularly considering our incomplete knowledge of the fossil record.<br /><br />News headlines touting <em>A. sediba</em> as the "missing link" between humans and apes is misguided on multiple levels. The term "missing link" comes from an outmoded understanding of evolution. Moreover, humans did not suddenly appear with <em>Homo</em>. This is a gross over-simplification of how evolution works. We should not expect to see a momentous change between the first members of a new species or genus and their parent population. Indeed, there is considerable debate as to whether members of the species <em>H. rudolfensis</em> (e.g. KNM-ER 1470) and <em>H. habilis</em> (e.g. OH 24 a.k.a. "Twiggy"), which lie on the generic dividing line, would actually be more accurately classified as australopithecines. I've seen grown men (it seems to be men that get most bent out of shape about such technicalities) argue vehemently over such taxonomic subtleties. Evolutionary theory would dictate that the line between <em>Homo</em> and <em>Australopithecines</em> be a fuzzy one. In fact, if we had a complete fossil record it would be near impossible to know where to draw the line between different genera and species. <br /><br />In the meantime, more individuals are being slowly uncovered at Malapa. Among these finds, are the arms bones of a 12 – 18 months old infant uncovered metres away from the two published specimens. Whether<em> A. sedib</em>a maintains it australopithecine designation or not, is much less interesting than what this population tells us about hominin variation circa 2 million years ago.<br /><br /><strong>References</strong><br />Lee R. Berger, Darryl J. de Ruiter, Steven E. Churchill, Peter Schmid, Kristian J. Carlson, Paul H. G. M. Dirks, Job M. Kibii (2010). Australopithecus sediba: A New Species of Homo-Like Australopith from South Africa Science, 328, 195-204: <a href="https://dx.doi.org/10.1126/science.1184944" rel="external">10.1126/science.1184944</a><br /><!-- AddThis Button BEGIN --><br /><body><script type="text/javascript">var addthis_pub="4a1c2d6a388b86af";</script><br /><a href="https://www.addthis.com/bookmark.php?v=20" onmouseover="return addthis_open(this, '', '[URL]', '[TITLE]')" onmouseout="addthis_close()" onclick="return addthis_sendto()"><img src="https://s7.addthis.com/static/btn/lg-share-en.gif" width="125" height="16" alt="Bookmark and Share" style="border:0"/></a><script type="text/javascript" src="https://s7.addthis.com/js/200/addthis_widget.js"></script><!-- AddThis Button END --></body><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-8341413108800772187?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0tag:blogger.com,1999:blog-2901919545584981466.post-64886897347513512792010-04-05T07:07:00.000-07:002010-04-05T15:10:40.114-07:00Taking a walk along our evolutionary trail<div class="image-right"><img class="imageStyle" alt="Gait_keepers" src="/files/laetoli_gait.jpg" width="290" height="349"/></div>As the rain began to clear over the region a couple of hominins could be seen walking across the blackened earth. The sun was beginning to break through the mist, exploding in a rainbow of colours. The volcano had been making periodic muffled groans since the last eruption…<br /><br />
Some 3.6 million years ago the now extinct Sadiman volcano erupted in Laetoli, Tanzania. It released a plume of ash into the atmosphere. This was the rainy season and the rains changed ash into mud. Elephants, antelopes, hares, giraffes, pigs, rhinos, as well as some bird species walked over the muddied terrain. Among the footprints were those from a pair of (and perhaps even three) hominins, walking side-by-side. A second eruption released more ash into the air covering over the footprints, preserving them as a layer of tuff. <br /><br />And so the it remained for more than three-and-a-half million years.<br /><br />Mary Leakey sent an expedition to investigate Laetoli in 1974. One afternoon in 1976, a group of paleontologists were passing the time by throwing elephant dung at each other. Admidst the mud flinging, palaeontologist Andrew Hill found himself standing atop the now eroded ash layer. Archaeologists set about painstakingly excavating the footprints. The layer was friable and crumbled easily. After years of meticulous excavation, the footprints were exposed in all their glory; the grand prize being the fifty metre trail left by the hominins.<br /><br />They are perhaps the clearest evidence for the early adoption of bipedal walking in our lineage. The footprints are thought to belong to <em>Australopithecus afarensis</em>, the species which included the famous fossil Lucy. However, there has been some debate as to whether these tracks represent fully bipedal locomotion or were more similar to the bent-knee, bent-hip gait seen when modern chimpanzees adopt a bipedal locomotion.<br /><br />In a study that recently appeared in the journal <em>PLoS ONE</em>, human subjects were asked to walk over a specially constructed walkway. The surface of the track was covered with a damp sand, to mimic the soft underfoot condition that existed at Laetoli when the footprints were laid-down. The subjects walked twice across the trackway and then a further two times assuming a bent-knee, bent-hip gait. Walking with a normal modern human gait produced foot impressions with nearly equal heel and toe depths. In contrast, the bent knee gait resulted in footprints with deeper toe impressions than heel impressions. When non-human apes walk bipedally, weight is transmitted from the heel, along the outside of the foot, with toe-off occurring around the middle of the foot. We on the other transmit weight along the heel to the ball of the foot, finally toeing-off with the big toe. This is the more efficient way to walk bipedally. The impressions from Laetoli best match the pattern made by modern humans. <br /><br />However I would be cautious about drawing too many conclusions from this study. One major drawback of this study is that walking with a bent-knee, bent-hip gait is not a natural gait for us. The impressions left by modern humans walking with this posture are probably not exactly the same as the footprints that a chimpanzee would leave when walking upright. While this study suggests that these hominins walked with a gait similar to our own, there is still room for debate as to exactly how similar the footprints are to our own. Regardless of these drawback, this study is a step in the right direction (no pun intended).<br />
<br /><strong>References</strong><br />Raichlen, D., Gordon, A., Harcourt-Smith, W., Foster, A., & Haas, W. (2010). Laetoli Footprints Preserve Earliest Direct Evidence of Human-Like Bipedal Biomechanics PLoS ONE, 5 (3) DOI: <a href="https://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0009769" rel="external">10.1371/journal.pone.0009769</a><br /><!-- AddThis Button BEGIN --><br /><body><script type="text/javascript">var addthis_pub="4a1c2d6a388b86af";</script><br /><a href="https://www.addthis.com/bookmark.php?v=20" onmouseover="return addthis_open(this, '', '[URL]', '[TITLE]')" onmouseout="addthis_close()" onclick="return addthis_sendto()"><img src="https://s7.addthis.com/static/btn/lg-share-en.gif" width="125" height="16" alt="Bookmark and Share" style="border:0"/></a><script type="text/javascript" src="https://s7.addthis.com/js/200/addthis_widget.js"></script><!-- AddThis Button END --></body><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-6488689734751351279?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0tag:blogger.com,1999:blog-2901919545584981466.post-65561077197001631932010-04-01T07:58:00.000-07:002010-04-01T15:43:39.320-07:00The abrupt increase in brain size that wasn't?In an <a href="https://www.guardian.co.uk/technology/2010/mar/28/colin-blakemore-how-human-brains-got-bigger" rel="external">interview</a> that recently appeared in the <em>Guardian,</em> neurobiologist Colin Blakemore has overstepped the mark in his discussion of the evolution of the human brain. There are a number of problems with Blakemore's thesis that have been covered more than adequately by <a href="https://whyevolutionistrue.wordpress.com/2010/03/28/british-biologist-tells-fanciful-tales-about-brain-evolution/" rel="external">Jerry Coyne</a> and <a href="https://johnhawks.net/weblog/reviews/brain/paleo/blakemore-brain-evolution-2010.html" rel="external">John Hawks</a>. I wish to focus on the claim that there was an "abrupt" increase in brain size in hominins around 200,000 years ago. Blakemore presents his argument as follows:<br /><br /><ul><em>The question is: why is [our brain] so big compared to the brains of our predecessors, such as Homo erectus? Until 200,000 years ago, there had been a gradual increase in brain size among hominins, starting three million years ago. Then, abruptly, there was a remarkable increase of about 30% or so.</em></ul><br /><img class="imageStyle" alt="pleistocene_brain_size-1" src="/files/pleistocene_brain_size-1.png" width="480" height="360"/><br /><br />John Hawks is not convinced that there is any abrupt change in cranial capacity. Referring to the above graph showing endocranial volume against time he writes:<br /><ul><em>As you can see, there's no sudden jump 200,000 years ago, or at any other time. The data, such as they are, are consistent with a single pattern of increase over time, as pointed out by Sang-Hee Lee and Milford Wolpoff (2003).<br /><br />Heck, it's the </em><strong><em>lack</em></strong><em> of a sudden jump that has gotten all the attention. Because if "modern" humans suddenly showed up in Africa 200,000 years ago, and all of a sudden had vastly larger brains than any other hominins, wouldn't that be a simple and tidy story? Don't you think we'd all be talking about the sudden origin of modern humans as reflected by their larger brains?<br /><br />It just didn't happen.</em></ul><br />I decided to take the data from the Lee and Wolpoff paper and compare the periods prior and subsequent to 200,000 years ago. As Hawks eluded to, the data can be explained by a linear model. However, this is not very helpful since we can easily fit a line or curve to just about any data. More to the point, a single fitted line doesn't tell us much about any changes in the data. The red line in the graph below corresponds to the best fit line for the entire dataset (<em>r</em> = 0.81). The green and orange lines are the best fit lines for the two time periods we are considering. We can see that slopes of all three lines differ appreciably from one another. An analysis of covariance test confirms that there is a significant difference in cranial capacity between the two time periods, after we control for time. The model is statistically significant: F(1, 84) = 107, p < 0.001.<br /><img class="imageStyle" alt="brain_size" src="/files/brain_size-2.jpg" width="480" height="348"/><br />Another way to consider our data is to look at the residuals. The residuals are simply the difference between our true values and the best fit line of our model. A good way to think about residuals is to imagine rotating our data above anticlockwise until the best fit line is horizontal. Since a horizontal line has a slope of zero, it also has a zero correlation with the x-variable, in our example time. In so doing, we can consider the differences in the residuals, having controlled for time. When we compare the residuals using the best fit line the means for the two time periods (separated by a grey dashed line) are significantly different. The model is also statistically significant: t(84) = -3.9994, p < 0.001. The mean difference in cranial capacity between the two periods is 122 cc; a difference of 31%. This corresponds well with Blakemore's figure. However, it is important to note that <strong>this is the mean difference between the two periods and does not necessarily indicate an abrupt change at 200,000 years ago.</strong><br /><img class="imageStyle" alt="residuals" src="/files/residuals.jpg" width="480" height="348"/><br />While the numbers seem to agree with the hypothesis of a marked increase in cranial size for the later period, I think the weight Blakemore gives it is rather foolish. The fossil record is patchy and likely unrepresentative of the true cranial variation of past hominins. As Jerry Coyne rightfully points out, a <em>geologically</em> sudden change in the fossil record may simply reflection how erratic it is. We already saw <a href="/index.php?id=4152453199173583192" rel="external">how cranial size can change markedly in 30,000 years</a> – little more than a blip on the time scale that we are considering here. The gradual decrease in cranial capacity since the early Upper Palaeolithic would seem geologically sudden when considered on the above timescale. The size of the fossil record is small enough that the discovery of five or six new specimens could mean having to revise our figures once again. <br /><br />Another problem is that calculating cranial capacity is not an exact science. While advances have been made in calculating cranial capacity, in many cases it should still be considered a best guess (de Miguel and Henneberg, 2001). This is particularly the case for palaeoanthropological material which tends to come out of the ground fragmented and deformed. With all its drawbacks, the fossil record is often all we have to answer some of our most pressing questions. At the same time, we need to always be conscious of what the record can and cannot tell us, and avoid the temptation to tell "fanciful tales".<br /><br /><strong>References<br /></strong><br />De Miguel C and Henneberg M (2001) Variation in hominid brain size: how much is due to method? Homo 52: 3–58.<br /><br /><a href="https://www-personal.umich.edu/~wolpoff/Papers/Brain%20Size.pdf" rel="external">Lee S-H and Wolpoff MH (2003) The pattern of evolution in Pleistocene human brain size. Paleobiology 29:186-196.</a><br /><!-- AddThis Button BEGIN --><br /><body><script type="text/javascript">var addthis_pub="4a1c2d6a388b86af";</script><br /><a href="https://www.addthis.com/bookmark.php?v=20" onmouseover="return addthis_open(this, '', '[URL]', '[TITLE]')" onmouseout="addthis_close()" onclick="return addthis_sendto()"><img src="https://s7.addthis.com/static/btn/lg-share-en.gif" width="125" height="16" alt="Bookmark and Share" style="border:0"/></a><script type="text/javascript" src="https://s7.addthis.com/js/200/addthis_widget.js"></script><!-- AddThis Button END --></body><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-6556107719700163193?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0tag:blogger.com,1999:blog-2901919545584981466.post-16886924940067651692010-03-25T08:07:00.000-07:002010-03-28T16:10:56.356-07:00Finger points to new human<div class="image-right"><img class="imageStyle" alt="dn18699-1_1-thumb" src="/files/denisova.jpg" width="180" height="241"/></div><a href="https://lh3.ggpht.com/_ugVSf4InVp0/S6rAiK8INcI/AAAAAAAAAtM/KRdEE_-7otk/s800/dn18699-1_1.jpg"><br /></a>A team of archaeologists have found the bone of a little finger while digging at Denisova Cave in the Altai Mountain, located in southern Siberia. The size of the bone suggests that it came from a child between five and seven years of age. It is difficult to distinguish between different species of humans based solely on the morphology of a single finger bone. However, the tentative dates put the age of the bone at between 30,000 and 50,000 years ago; a window of time when both Neandertals and modern humans coexisted in Eurasia.<br /><br />In order to determine which species the little finger came from, Johannes Krause of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany sequenced the complete mitochondrial DNA (mtDNA) from the finger bone and compared its DNA with that of modern humans and Neandertals. What they found surprised everyone involved in the project. The mtDNA of Denisova did not match that of modern humans or Neandertals. In fact it last shared a common ancestor with us and Neandertals in Africa around a million years ago.<br /><br />We know of three major hominin migrations out of Africa. The first occurred with <em>Homo erectus</em> around 1.9 million years ago, followed by the ancestors of Neandertals sometime between 500,000 and 300,000 years ago, and finally modern humans around 50,000 years ago. This makes the Denisova specimen too late to be part of the <em>Homo erectus</em> exodus and too early to part of the other two.<br /><br />However, it may be a little premature to declare this a new species of human. Svante Pääbo's team is already busy sequencing the nuclear DNA of the Denisova specimen. One, albeit unlikely, possibility is that this will turn out to be a representative of an outlier Neandertal population. Previous studies have found a wide diversity in both the morphology and mitochondria of geographically separated Neandertal populations. Until the nuclear DNA has been mapped it is not possible to definitively say if we are really dealing with a new species of human. However, if this does turn out to be the case, it would mean that we shared the globe with at least three other species of humans as late as 40,000 years ago.<br /><span style="color:#0080FF;"><!-- AddThis Button BEGIN --><br /><body><script type="text/javascript">var addthis_pub="4a1c2d6a388b86af";</script><br /><a href="https://www.addthis.com/bookmark.php?v=20" onmouseover="return addthis_open(this, '', '[URL]', '[TITLE]')" onmouseout="addthis_close()" onclick="return addthis_sendto()"><img src="https://s7.addthis.com/static/btn/lg-share-en.gif" width="125" height="16" alt="Bookmark and Share" style="border:0"/></a><script type="text/javascript" src="https://s7.addthis.com/js/200/addthis_widget.js"></script><!-- AddThis Button END --></body></span><br /><br /><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-1688692494006765169?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0tag:blogger.com,1999:blog-2901919545584981466.post-15455214279182960622010-03-22T07:04:00.001-07:002010-03-22T07:06:52.826-07:00RSS woesDue to some internal changes to my blog the RSS feed may have stop working for some subscribers. If your RSS feed for Ad Hominin is not updating correctly, please resubscribe using this <a href="https://feeds.feedburner.com/AdHominin">link</a> or by clicking on the "Subscribe to Ad Hominin" widget in the sidebar. Sorry for any inconvenience caused.<br /><br />If you have not already subscribed to Ad Hominin now would be a good time to do so. It is a great way to keep up to date with any new posts.<br /><br /><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-1545521427918296062?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0tag:blogger.com,1999:blog-2901919545584981466.post-66011579967012562722010-03-22T04:16:00.000-07:002010-03-22T04:29:34.182-07:00Why people believe in homeopathy<div class="image-right"><img class="imageStyle" alt="sewage" src="/files/sewage.jpg" width="480" height="318"/></div><ul><em>How long will it take mankind to learn that while they listen to "the speaking hundreds and units, who make the world ring" with the pretended triumphs they have witnessed, the "dumb millions" of deluded and injured victims are paying the daily forfeit of their misplaced confidence! </em></ul><br />Almost 170 years after Oliver Wendell Holmes read these words to the Boston Society for the Diffusion of Useful Knowledge the pseudoscience of homeopathy continues to thrive. An EU commission statement estimates that some 30 million people in the EU use homeopathy, while the WHO estimates that around 500 million in the world use it.<br /><br />
Since Wendell Holmes' time a colossal body of evidence has been amounted showing that homeopathy has no medicinal effect beyond the placebo effect. The core concepts of homeopathy fly in the face of science and logic. homeopathy uses highly dilute solutions of a substance to treat disease. Most homeopathic solutions are so dilute that there is almost no chance that they will contain even a single molecule of the original active agent. Counterintuitively, homeopathic practitioners claim that the more dilute the solution, the stronger the homeopathic remedy. This contradicts the well-known phenomenon of dose response, which says that the more of a chemical an organism is exposed to, the greater the effect. Take one sleeping pill and it will help you sleep; take two and the effect is even more powerful; take 100 sleeping pills and you are not likely to wake up … ever! On the other hand, homeopaths would suggest that the more dilute the solution, the more "powerful" the effect. But how could a solution of something that doesn't contain even a single molecule of active ingredient have any effect? Here, things get even more bizarre. They suggest that water has memory. Seemingly, water has the ability to remember contact with certain substances, while at the same time being able to forget all the raw sewage and fecal matter that it has been in contact with. If homeopathy is nothing but water, why do so many people continue to believe it works?<br /><br />Scientists and sceptics who engage with advocates of homeopathy usually end up throwing their hands up in the air in frustration. The reason is that most people who have come to believe in homeopathy do not do so based on scientific data or for particularly rational reasons. As such, it is unlikely that anyone who did not come to a particular position based on logic or reason will be argued out of that position using logic and reason. Indeed, no amount of rational argument will convince proponents of this modality that they are misguided. Holmes was well aware of the ineffectiveness such an exercise, stating that "… it is impossible not to realize the entire futility of attempting to silence this asserted science by the flattest and most peremptory results of experiment."<br /><br />It is tempting to criticise such beliefs on the grounds that the people who hold them are somehow lacking basic cognitive skills. In fact, people who believe in all kinds of strange things are often very rational in other aspects of their life. I would instead argue that the faulty thinking that many engage in is a byproduct of our mind works. The human brain evolved not only to explain the world around us; it evolved to deal with an innumerable amount of tasks. Cultural transmission does not occur by downloading information, as was once believed, but rather is based on an inferential system. We classify things in our environment into ontological categories. Most things we encounter in our environment fall into one of the following groups: person, animal, natural object, tool and plant. Each ontological category has a set of characteristics that define it and set it apart from other categories. We make certain inferences about objects based on which ontological category it belongs to. For instance, we are not surprised when a dog walks down the street but would find it strange if we saw an oak tree doing so. Locomotion is part of our mental template for people and animals but not plants. We find certain counter-intuitive notions more memorable than blander ones, a prerequisite for a successful <a href="https://en.wikipedia.org/wiki/Meme" rel="external">meme</a>. Superstitious beliefs often combine ontological beliefs with a category violation. For instance, disembodied souls and inanimate statues that can cry, hear or bleed represent category violations for a person and a natural object respectively. However, not all superstitious beliefs are equally believable. While the belief in ghosts is widespread, the belief that ghosts cannot think and have desires is virtually non-existent. Violations must allow for further inferences, otherwise they result in cognitive dead ends. Although few of my readers literally believe in superheroes and zombies, that does not stop us from making inferences about what their needs, wants and limits would be if they did exist.<br /><br />The idea that water has memory is a categorical violation. Memories are characteristic of a person or animal but not a natural object. Crucially, the belief that water has memory does not block further cognitive inferences. Conversely, we would find it much more difficult to believe that water remembers the substances that other water had been in contact with. This type of belief is rare since it prevents us from making further inferences. We have experience with the concept of remembering things that <em>we</em> have been in contact with but don't have experience of what it is like to remember things<em> other people</em> have been in contact with. People I met when I was younger — people who I have not seen for many years – still have an influence on me now. Likewise, it is not such a large cognitive leap to believe that substances that came into contact with water still have an influence over it.<br /><br />Another important component of homeopathy is vitalism. The idea that we are more than just the aggregate of chemical and mechanical processes is an appealing one. Vitalism appeals to our core intuitions. Vitalists believe that the laws of science are inadequate to explain life processes. There must be something more to it – a soul or some elan vital. All of us operationally view ourselves as both body and mind, even those of us who outright reject the idea of a disembodied self or soul. The self is not something that governs the brain, rather the self is the outcomes of brain processes. However, our brain does a wonderful job of convincing us otherwise. The father of homeopathy, Samuel Hahnemann, saw the vital force as a "spirit like" force that maintained life. He believed that the inner vital force maintained the body's internal balance. When the body became ill it would push the illness outwardly, causing the symptoms of the disease or illness to manifest. Many homeopaths believe that all disease come down to one thing — the disturbance of the vital force. They believe that only homeopathic remedies stimulate the vital force into action.<br /><br />Sympathetic or imitative magic is found in cultures the world over. Sympathetic magic is based on two related concepts: the law of similarity and the law of contagion. The former states that like things produce like effects, while the latter is the idea that items that have been in contact continue to affect each other. Perhaps the best known example of sympathetic magic is the use of voodoo dolls to place a curse on a specific person. <a href="https://en.wikipedia.org/wiki/Cargo_cult" rel="external">Cargo cults</a> would also engage in sympathetic magic by building landing strips and radio towers to encourage the airplanes that delivered them precious cargo during World War II to come back again. In the past, whooping cough and a sore throat were often treated by tying knots in a piece of string and hanging it around the ill person's neck. The knots were supposed to symbolise the tightness in the person's throat. Liverworts have been used for hundreds of years as a cure ailments of the liver, probably because of the plant's resemblance to the liver. A cure for pneumonia was to tie the lungs of a sheep to the soles of the feet of a patient. Golden objects and butter were commonly used as cures for jaundice. It was believed that warts could be cured by rubbing them on a frog, most likely because of the frog's warty appearance. The use of oysters, rhinoceros horns and tiger penises as aphrodisiacs are all examples of sympathetic thinking. The list goes on and on.<br /><br />In a similar vein, homeopathy uses the concept of "like cures like." It is based on the idea that substances which produce symptoms similar to those of a particular illness can treat that illness. For instance, homeopaths may treat a person suffering from hay fever with an onion extract, since both produce watery eyes and a runny nose. The idea that water can still remember things it was previously in contact with, is an example of the "law of contagion." In this regard, homeopathy is similar to the concept of holy water that is common to many religions.<br /><br />The brain processes that lead someone to believe in homeopathy exist in all of us. Our mental capacities evolved to aid in our survival, with erroneous beliefs an emergent property of our intuitive psychology. We are all prone to cognitive dissonance aversion, memory illusion, and confirmation bias. Such cognitive traps are probably adaptive and essential to mental well-being. The biologist Lewis Wolpert suggests that scientific thinking is in fact aberrant. Science is a conscious departure from intuition and common sense. Homeopathy is parasitic upon brain processes that originally evolved for other activities. If we want to understand <em>why</em> people believe in homeopathy, we must first understand <em>how</em> such beliefs enlist our evolved mental capacities.<br /><br /><strong>References and further reading <br /></strong>
Boyer, P (2001): Religion Explained. Evolutionary Origins of Religious Thought. New York: Basic Books.<br /><br />
Holmes OW (1842). Homœopathy, and its kindred delusions; two lectures delivered before the Boston society for the diffusion of useful knowledge, Boston: William D. Ticknor.<br /><br />
Wolpert, L (1993). The unnatural nature of science. Cambridge, MA: Harvard University Press. <br /><br /><span style="font-size:10px; ">
Above photo </span><span style="font-size:10px; "><a href="https://www.flickr.com/photos/stuckincustoms/314036511/">"Hot Raw Sewage"</a></span><span style="font-size:10px; "> by Stuck in Customs is used under creative commons license.<br /></span><!-- AddThis Button BEGIN --> <script type="text/javascript">var addthis_pub="4a1c2d6a388b86af";</script><script type="text/javascript" src="https://s7.addthis.com/js/200/addthis_widget.js"></script><!-- AddThis Button END --><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-6601157996701256272?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0tag:blogger.com,1999:blog-2901919545584981466.post-32595258933313757262010-03-21T13:23:00.000-07:002010-03-21T13:26:21.177-07:00Changes to commenting serviceI have received notification that my comment service Haloscan will be closing. Unfortunately, there is no way to export older comments. Since my blog is relatively new and only gets a few comments, I think the move to a new comments system should be a minor inconvenience. With that said it hasn't been an easy decision. I will be migrating the comments to the Disqus service. Thanks to everybody who has commented on my past posts. Your feedback and comments are very important to me. <br /><br />The upside of these changes means that I can use a plugin called RapidBlog that allows me to use the Google Blogger service to write and publish blog posts. Migrating to Blogger means that I'm no longer tied to my machine and can post while on the road. The main reason I didn't use this earlier was that it meant losing comments, which is now inevitable. Hopefully the move to Google Blogger will be invisible for you the reader. Thank you for your understanding and continued support.<div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-3259525893331375726?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0tag:blogger.com,1999:blog-2901919545584981466.post-52008979988401815922010-03-17T05:21:00.000-07:002010-03-21T13:38:08.041-07:00Four Stone Hearth 88<img class="imageStyle" alt="four-stone-hearth" src="/files/four-stone-hearth.jpg" width="505" height="63"/><br /><strong><br /></strong>Welcome to the St. Patrick’s Day special edition of Four Stone Hearth 88. <a href="https://fourstonehearth.net/" rel="external">Four Stone Hearth</a> 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 <a href="mailto:arador[AT]algonet.se" rel="external">Martin Rundkvist</a>. The next issue will be hosted at the <a href="https://scienceblogs.com/gregladen/" rel="external">Greg Laden’s blog</a> on 31 March.<br /><br />Online Degrees.net has posted their <a href="https://www.onlinedegrees.net/blog/2010/100-best-blogs-for-anthropology-students/" rel="external">100 best blogs</a> for anthropology students. It is a wonderful resource that I recommend checking out. Now on with this round of carnival posts.<br /><br /><span style="font-size:14px; color:#000000;font-weight:bold; "><u>Archaeology</u></span><br /><div class="image-right"><a href="https://inventerare.wordpress.com/2010/03/15/le-thoronet-abbey/" rel="external"><img class="imageStyle" alt="le-thoronet-abbey4" src="/files/le-thoronet-abbey4-2.jpg" width="168" height="224"/></a></div>Luis over at the blog Leherensuge <a href="https://leherensuge.blogspot.com/2010/03/strange-case-of-glozel-findings.html" rel="external">reports</a> on the alleged archaeological forgery at <strong>Glozel</strong>. The controversy revolves around a hoard of objects that appear to date from different time periods. The death of the principle protagonist, Emile Fradin, has renewed interest in these alleged artefacts. Are these the genuine article or just another <a href="https://en.wikipedia.org/wiki/Piltdown_Man" rel="external">Piltdown</a>. Decide for yourself.<br /><br />Over at Testimony of the spade, Magnus Reuterdahl <a href="https://inventerare.wordpress.com/2010/03/15/le-thoronet-abbey/" rel="self">reflects on</a> how extant <strong>abbeys</strong> can give us a greater appreciation for those which over time have falling into ruin.<br /><br />Martin Rundkvist over at Aardvarchaeology, has <a href="https://scienceblogs.com/aardvarchaeology/2010/02/beautiful_vendel_period_jewell.php" rel="external">mixed feelings</a> about his <em>Magnum opus</em> entitled "Domed oblong brooches of Vendel Period Scandinavia.” Martin relays how sticking to your <strong>“scholarly ideals”</strong> is not always the easiest road to career advancement.<br /><br /><br /><span style="font-size:14px; color:#000000;font-weight:bold; "><u>Biological anthropology</u></span><span style="font-size:13px; font-weight:bold; "><br /></span>In a recent post, <a href="/files/shrinking_human_brain.html" rel="external">I discuss</a> the trend towards decreased head size starting around 30,000 years ago, which continues today.<br /><br />Carl Feagans at ahotcupofjoe looks at <strong><em><a href="https://ahotcupofjoe.net/2010/03/getting-there-is-half-the-fun-early-homo/" rel="external">the dispersal of early Homo out of Africa</a></em></strong>.<br /><br />Last year, amidst much media fanfare everybody came to know about our 47 million year old purported ancestor “<strong>Ida”</strong>. This was indeed a spectacularly preserved fossil specimen, which preserved the outline of the body as well as the stomach contents. However, the scientific community at the time aired scepticism about the claim that it was on the evolutionary line that led to us. Many palaeontologists and primatologists were quick to point out that this primate looked more lemur-like. Well, it turns out that they were right. In a paper published in the Journal of Human Evolution shows that this species, <strong><em>Darwinius masillae</em></strong>, belonged to an extinct branch of primates, most closely related to lemurs and lorises. Brian Switek of the Laelaps <a href="https://scienceblogs.com/laelaps/2010/03/almost_ten_months_ago_an.php" rel="external">gives a synopsis of the paper</a>, while Eric Michael Johnson at Primate Diaries gives <a href="https://scienceblogs.com/primatediaries/2010/03/darwinius_is_not_a_human_ances.php" rel="external">a very accessible account</a> of the whole affair.<br /><br /><div class="image-right"><a href="https://artsonearth.com/2008/11/golden-snub-nosed-monkeys.html" rel="external"><img class="imageStyle" alt="goldenmonkey11vl2" src="/files/goldenmonkey11vl2.jpg" width="160" height="170"/></a></div>John Hawks is a fly on the wall at a <strong><a href="https://johnhawks.net/weblog/reviews/genetics/mtdna_migrations/african-american-mtdna-ely-2010.html" rel="external">symposium on genetics and genealogy of the African Diaspora</a></strong>. He reports on Fatimah Jackson’s genetic work in Africa and African-Americans, in particular the idea of "ethnogenetic layering”.<br /><br />Raymond Ho at the Prancing Papio blog has <a href="https://theprancingpapio.blogspot.com/2010/03/shift-from-polygyny-to-polygamous.html" rel="external">a review of a paper</a> on the changing mating systems in <strong>Sichuan snub-nosed monkeys</strong>. The pieces offers some plausible evolutionary reasons for the shift from polygynous to polygamous mating systems.<br /><br /><br /><span style="font-size:14px; color:#000000;font-weight:bold; "><u>Linguistic anthropology</u></span><br />Valerie Williamson <a href="https://linguistic-anthropology.suite101.com/article.cfm/disappearing-siberian-minority-languages" rel="external">writes</a> about Siberian <strong>languages, which are on the verge of extinction</strong>. The race is on for linguists to document these languages before they disappear completely.<br /><br /><br /><span style="font-size:14px; color:#000000;font-weight:bold; "><u>Socio-cultural anthropology</u></span><br /><div class="image-left"><a href="https://www.flickr.com/photos/ipuzzled/152290154/" rel="external"><img class="imageStyle" alt="152290154_60922538fa_o" src="/files/152290154_60922538fa_o.jpg" width="264" height="221"/></a></div>In the spirit of the occasion, anthropologyworks has <a href="https://anthropologyworks.com/?p=1708" rel="external">compiled a bibliography</a> of social anthropology articles on <strong>Ireland and the Irish</strong>. <br /><br />Krystal, over at Anthropology in Practice, <a href="https://anthroinpractice.blogspot.com/2010/03/food-cart-vendors-get-hip-to-digital.html" rel="external">talks about a street vendor</a> in her city that has started to take <strong>coffee orders via text message</strong>. Is this merely a fad or society simply adapting to our greater reliance on digital media?<br /><br />Ronald Kephart a.k.a. the Cranky Linguist <a href="https://crankylinguist.blogspot.com/2010/03/educational-malpractice-at-liberty.html#comments" rel="external">reports on the educational malpractice</a> of <strong>teaching religion as science</strong> at Liberty University.<br /><br /><div class="image-right"><img class="imageStyle" alt="CocaColaIndia" src="/files/cocacolaindia.gif" width="185" height="230"/></div>Eric Michael Johnson reports on the <strong>Itineraries of Exchange symposium</strong>. <a href="https://scienceblogs.com/primatediaries/2010/03/finding_hope_amidst_bartered_skulls.php" rel="external">This piece</a> gives us an insight how indigenous groups have managed to maintain traditions and self-determination in the face persecution, racism, and exploitation.<br /><br />Also check out Eric’s <a href="https://scienceblogs.com/primatediaries/2010/03/coca-cola_in_india_good_till_t.php" rel="external">article</a> on <strong>Coca Cola’s over-exploitation</strong> of water resources in India. It seems that the slogan “Good Till the Last Drop" has a more pernicious meaning.<br /><br />A Very Remote Period Indeed has a wonderfully titled piece “<a href="https://averyremoteperiodindeed.blogspot.com/2010/03/mad-neanderthals-peer-review-and.html#links" rel="external">Mad Neanderthals, peer review and scholarly publication</a>”. Controversy has surrounded the journal <strong>Medical Hypotheses</strong> since its very conception. This journal is unique in that it doesn’t have a peer review system, while promoting controversial and thought-provoking ideas. However, Julien Riel-Salvatore tells of the comment he published in this journal in response to an article that proposed that Spongiform Encephalopathies may have led to the demise of the <strong>Neanderthals</strong>. Julien does not think the biggest problem is with <strong>the journal’s incredibly low standards</strong> but rather with the academic publishing house Elsevier, who by purchasing Medical Hypotheses has given it an air of legitimacy.<br /><br />That’s it for another edition of Four Stone Hearth. Happy St. Patrick’s Day to one and all!<br /><br /><span style="font-size:10px; font-weight:bold; ">Image Credits</span><span style="font-size:13px; "><br /></span><span style="font-size:10px; ">Golden snub nosed monkey from </span><span style="font-size:10px; "><a href="https://artsonearth.com/2008/11/golden-snub-nosed-monkeys.html" rel="external">artsonearth</a></span><span style="font-size:10px; ">,<br /></span><span style="font-size:10px; "><a href="https://commons.wikimedia.org/wiki/File:CocaColaIndia.gif" rel="external">CocaColaIndia</a></span><span style="font-size:10px; "> by Carlos Latuff under the Wikimedia Commons licence.<br /></span><span style="font-size:10px; ">Marilyn Monroe reading James Joyce. Flickr creative commons licensed content by user </span><span style="font-size:10px; "><a href="https://www.flickr.com/photos/ipuzzled/152290154/" rel="external">I, Puzzled</a></span><span style="font-size:10px; ">.<br /></span><!-- AddThis Button BEGIN --><br /><body><script type="text/javascript">var addthis_pub="4a1c2d6a388b86af";</script><br /><a href="https://www.addthis.com/bookmark.php?v=20" onmouseover="return addthis_open(this, '', '[URL]', '[TITLE]')" onmouseout="addthis_close()" onclick="return addthis_sendto()"><img src="https://s7.addthis.com/static/btn/lg-share-en.gif" width="125" height="16" alt="Bookmark and Share" style="border:0"/></a><script type="text/javascript" src="https://s7.addthis.com/js/200/addthis_widget.js"></script><!-- AddThis Button END --></body><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-5200897998840181592?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0tag:blogger.com,1999:blog-2901919545584981466.post-41524531991735831922010-03-14T17:12:00.000-07:002010-03-21T13:38:07.009-07:00The incredible shrinking human brain<div class="image-left"><a href="https://www.timesonline.co.uk/tol/news/science/article7060327.ece#cid=OTC-RSS&attr=6980618?utm_source=twitterfeed&utm_medium=twitter" rel="external"><img class="imageStyle" alt="Brain_696621a" src="/files/brain_696621a.jpg" width="221" height="192"/></a></div>The Times Online recently ran<a href="https://www.timesonline.co.uk/tol/news/science/article7060327.ece#cid=OTC-RSS&attr=6980618?utm_source=twitterfeed&utm_medium=twitter" rel="external"> a story</a> about a French team that have made an <a href="https://en.wikipedia.org/wiki/Endocast" rel="external">endocast</a> by digitally scanning inside the skull of Cro-Magnon 1, perhaps the most famous of all Upper Palaeolithic skulls. The mould of Cro-Magnon highlights what has been long known about these European early modern humans since their first discovery in 1868 - they had bigger brains than us. In fact, average human brain size has been decreasing during the last 30,000 or so years. This revelation was rather troubling for nineteenth-century anthropologists who sought to link brain size with intelligence. Not only did these early modern humans have a larger brain volume than us, but so too did the Neanderthals, who were regarded by many at the time as “a barbarous and savage race” (Schaaffhausen 1858). To add injury to insult, the decrease in head size coincides with some of the greatest cultural innovations in human history.<br /><br />The Times article forwards a number of the various hypotheses about why brain size has decreased. Antoine Balzeau reasons that <em>“the cerebellum — a brain structure linked to language and concentration — appears to take up a larger proportion of the head now than in the time of Cro Magnon 1.”</em> While it is true that the cerebellum is proportionally larger in modern humans, it is proportionally smaller than in apes, by around 20%. We still don’t know enough about brain function to be able to say what advantage, if any, a larger cerebellum would give us.<br /><br />Second up, is the suggestion that big heads are somehow an adaptation to cold climate. There are a number of problems with this idea. If having a large skull is an adaptation to cold environments we would expect to see such traits peaking in the aftermath of the Last Glacial Maximum around 20,000 years ago, many millennia after Cro-Magnon walked the earth. As a general rule people living in Arctic regions tend to have more rounded heads, unlike the long headed Cro-Magnon. What’s more, the limbs of Cro-Magnon and their kin are quite long, contradicting Allen’s Rule which predicts that species will evolve smaller appendages as an adaptation to colder climes. Their body type also differs markedly from that of Neandertals, for whom there is a better case to made of being cold-adapted.<br /><br />The article goes on to suggest diet as a driving force behind the decrease in head size. Cranial robusticity has indeed been shown to correlate with diet. It is important, however, to make the distinction between cranial size and robusticity. While the two are related they do not necessarily go hand in hand. While the Gravettian populations were undoubtedly more robust than most modern-day populations, they are not especially robust when compared to the Mesolithic populations of Téviec and Hoëdic or modern Aboriginal Australian or Fuegian populations. It is also unclear what dietary innovation could account for the decrease in head size. We have unambiguous evidence for the control of fire at around 250,000 years ago, while agriculture did not appear until around 10,000 years ago. The dates just don’t add up.<br /><br />The article suggest one more hypothesis for the downsizing of the brain: <em>“… with high infant mortality, only the toughest survived — and the toughest tended to have big heads.”</em> Infant mortality is an ever-present problem for humans because bipedalism has constrained the size of the birth canal. If anything, giving birth to a larger headed children is going to lead to <em>increased</em> mortality for both the mother and child. Indeed, natural selection has restricted <em>in utero </em>brain growth in humans, with a large proportion of brain development occurring outside of the womb. In most non-human primates, the brain is close to adult size by the first year of life. In humans, on the other hand, near-adult brain size is not reached until about ten years of age.<br /><br />Perhaps, the best explanation for the larger head size of our ancestors is one that the authors failed to mention – allometry. Bigger animals have bigger brains. While the cranial capacity for modern humans is large for a primate of our size, it is still only about a quarter of the size of that of an elephant. The decrease in brain size during the late Pleistocene was also accompanied by a decrease in body size. In other primates that show a decrease in brain size, there is an accompanying decrease in body size. Having a larger brain comes at a cost. The brain is a greedy glucose-guzzling tissue. The is possible that our smaller brain has allowed us to reallocate energy for other bodily functions.<br /><br /><strong>References and further reading<br /></strong>Henneberg M. Evolution of the human brain: is bigger better?. Clin Exp Pharmacol Physiol 1998, 25:745-749.<br /><br />Schaaffhausen H. On the crania of the most Ancient Races of Man. Müllers Archiv 1858:453.<br /><br />Ruff C, Trinkaus E, Holliday T. Body mass and encephalisation in Pleistocene Homo. Nature 1997: 387: 173–6.<br /><!-- AddThis Button BEGIN --><br /><body><script type="text/javascript">var addthis_pub="4a1c2d6a388b86af";</script><br /><a href="https://www.addthis.com/bookmark.php?v=20" onmouseover="return addthis_open(this, '', '[URL]', '[TITLE]')" onmouseout="addthis_close()" onclick="return addthis_sendto()"><img src="https://s7.addthis.com/static/btn/lg-share-en.gif" width="125" height="16" alt="Bookmark and Share" style="border:0"/></a><script type="text/javascript" src="https://s7.addthis.com/js/200/addthis_widget.js"></script><!-- AddThis Button END --></body><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-4152453199173583192?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0tag:blogger.com,1999:blog-2901919545584981466.post-1819182537236936732010-03-13T02:48:00.000-08:002010-03-21T13:26:16.588-07:00Four Stone Hearth submissionsI will be hosting a St. Patrick’s Day special edition of <a href="https://fourstonehearth.net/" rel="external">Four Stone Hearth</a> on Wednesday, March 17th. Four Stone Hearth is a fortnightly anthropology blog carnival. If you have read or written any interesting blog posts on archaeology, socio-cultural anthropology, bio-physical anthropology or linguistic anthropology in the last few weeks, please <a href="mailto:adhominin@[DELETE THIS]me.com" rel="self">email me</a> a link and I’ll be sure to include them.<div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-181918253723693673?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0tag:blogger.com,1999:blog-2901919545584981466.post-39096191638348375152010-03-09T00:47:00.000-08:002010-03-21T13:26:15.399-07:00100 best anthropology blogsThe Online Degrees.net blog has compiled a comprehensive list of the <a href="https://www.onlinedegrees.net/blog/2010/100-best-blogs-for-anthropology-students/" rel="external">100 Best Blogs for Anthropology Students</a>. This is a fantastic resource for <strong>anybody</strong> interested in anthropology.<div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-3909619163834837515?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0tag:blogger.com,1999:blog-2901919545584981466.post-77387726296795596292010-01-24T06:00:00.000-08:002010-03-21T13:38:04.091-07:00Paleo diet<div class="image-right"><a href="https://www.flickr.com/photos/lord-jim/2245362817/" rel="external"><img class="imageStyle" alt="2245362817_2cd6b263af" src="/files/2245362817_2cd6b263af.jpg" width="222" height="231"/></a></div>For many people the new year represents an occasion to set the clock back to zero and make a fresh start. We invariably eat too much during the festive season, only later to feel remorse for our gluttonous ways. With the new year comes the renewed goal of losing some of the 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 so-called 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. <br /><br />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? <br /><br />While certain human adaptations undoubtedly arose during the Palaeolithic, these are likely to be no more or less important than the adaptations of preceding and subsequent periods in our evolutionary history. Most of our genes evolved a long time before our ancestors were recognisable as primates, never mind humans. Moreover, humans continue to adapt to their diet today. Lactose tolerance is a good example of a trait that arose in many populations of humans after the Palaeolithic. Evolution exists on a continuum; it didn’t start and end sometime during the Palaeolithic.<br /><br />The Palaeolithic covers a period of around 2.5 million years, as well as an immense geographic range. Moreover, many species of humans lived in very diverse environments during this time. Proponents of the Paleo diet rarely specify what period and indeed which populations or species they use as their model. Food procurement methods changed dramatically over this time period. Over the course of the Palaeolithic, humans shifted from mostly scavenging their meat to systematic hunting. Even among modern hunter-gatherers there is great dietary variation. For instance, the diets of Inuits and Aboriginal Australians couldn’t be more different. Another consideration is that humans have been selectively breeding plants and animals over many millennia. Many of the domesticated varieties we see today are unrecognisable from their wild ancestors. As such, while the Paleo diet recommends greater reliance on meats and non-cultivated plants, it should be kept in mind that these probably bear little resemblance to the wild species our ancestors ate.<br /><br />The limb bones of the early Upper Palaeolithic Gravettian people are not only large but also have massive muscle attachments. Early humans were physically fit not only because of their diet but in large part due to their high mobility. Hunting and foraging expeditions would have required these groups to cover large distances. Demographic pressures impinging on these small bands of humans would also have further encouraged greater mobility.<br /><br />It is not disputed that the diet of early hunter-gatherers was much more varied than that of their agricultural counterparts. Early agriculturalists often had an over reliance on few food types, leading to various nutritional deficiencies and generally poorer health. However, there is little reason why this should be the case today. Our shops and markets are packed with varieties of food that our ancestors would be only able to dream off.<br /><br />Many of the recommendations of the Paleo diet are sensible, such as eating less processed foods, decreasing our sugar intake and increasing our dietary fibre. In this regard, the Paleo diet is on par with most governmental dietary recommendations. Why the need to dress it up in some romanticised account of how our ancestors ate? I will concede that versions of the Paleo diet are probably healthier than the diets most of us adhere to. However, the reasoning behind it is based on an immutable view of human prehistory, coupled with some poor evolutionary thinking.<br /><span style="color:#0080FF;"><!-- AddThis Button BEGIN --><br /><body><script type="text/javascript">var addthis_pub="4a1c2d6a388b86af";</script><br /><a href="https://www.addthis.com/bookmark.php?v=20" onmouseover="return addthis_open(this, '', '[URL]', '[TITLE]')" onmouseout="addthis_close()" onclick="return addthis_sendto()"><img src="https://s7.addthis.com/static/btn/lg-share-en.gif" width="125" height="16" alt="Bookmark and Share" style="border:0"/></a><script type="text/javascript" src="https://s7.addthis.com/js/200/addthis_widget.js"></script><!-- AddThis Button END --></body></span><br /><span style="font-size:9px; color:#666666;">Above photo modified from original by </span><span style="font-size:9px; color:#666666;"><a href="https://www.flickr.com/photos/lord-jim" rel="external">Lord Jim</a></span><span style="font-size:9px; color:#666666;"> under creative commons license.</span><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-7738772629679559629?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0tag:blogger.com,1999:blog-2901919545584981466.post-81848176618741114452009-12-19T14:40:00.000-08:002010-03-21T13:38:03.084-07:00Dangerous quote mines: a cautionary tale<div class="image-right"><img class="imageStyle" alt="matt_wedel" src="/files/matt_wedel.jpg" width="214" height="181"/></div><a href="https://sauroposeidon.net/" rel="external">Mathew John Wedel</a> (right) is a palaeontologist who specialises in sauropod dinosaurs. Recently, he was invited to be a talking head for Discovery Channel’s new series, <a href="https://press.discovery.com/us/dsc/programs/clash-dinosaurs/" rel="external">Clash of the Dinosaurs</a>. 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.<br /><br />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:<br /><em><ul>”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 </em><strong><em>this was sort of like a second brain to help control the back half of the body</em></strong><em>. 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.”</ul></em><br />I can only imagine the shock Matt experienced when this got edited down to:<br /><em><ul>“This was sort of like a second brain to help control the back half of the body.”</em> <em></ul></em><br />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 <a href="https://www.urbandictionary.com/define.php?term=nopology" rel="external">nopology</a>, even having the audacity to say: <em>“we were simply working on the show ever aware of the demands of our audience.”</em> And what about presenting the facts or fairly representing the views of the scientists?<br /><br />Thankfully, this story has a happy ending. Matt talked to a person high up at the Discovery Channel, who promised that the egregious portion would be promptly removed. Unfortunately, this misrepresentation of a scientist is not an isolated case and we would do well to understand why this happens and what can be done to prevent it. The first thing we should remember is that documentaries are, first and foremost, made for entertainment. As a result, most are written by screenwriters and have a predetermined script. One would think that the scientific facts write themselves but this is sadly not the case. It is the job of the film crew to interview specialists, all the time being conscious of the preplanned plot. Scientists should not be afraid to ask to see an outline of the plot. That way they have an idea of what pieces of information the production team are after. When documentary makers interview scientists they are generally looking for snippets that will propel the storyline. This is the reason why hours of footage eventually get edited down to mere seconds. Naturally, the more time you spend talking the greater the chances of something making it into the finally cut. However, this also means that there is more material that can be taken out of context. It is in the interviewee’s best interest to keep the conversation from wandering off course. This can be achieved by negotiating an hourly fee with the production company prior to any interview. Scientists shouldn’t be shy about demanding money for their time. Film crews will often have a budget for this but are normally not very forthcoming in divulging this information. As long as the film crew are cognisant of their budget, they are more likely to cut to the chase earlier on, rather than fishing around for juicy quotes.<br /><br />While it is tempting for experts to point out the flaws in refuted hypotheses, they are perhaps better off biting their tongues. This way, their words cannot be contorted to suggest that they are in fact a proponent of a viewpoint they firmly disagree with. However, if you are cornered into giving an opinion on a contrary idea it is perhaps best to let your body do the talking. If you can visibly demonstrate your disdain for a particular idea through your facial expressions, it makes it much harder for the editors to later manipulate your words in such a way that they contradict your body language. This requires scientists to really show and perhaps exaggerate their emotions, but heck, if one truly loves their profession that shouldn’t be too difficult to accomplish.<br /><br />It is important that scientists speak out against any media distortions of science. It is likely that Dangerous Ltd. felt some heat from the negative reaction of bloggers and commentators, subsequent to <a href="https://svpow.wordpress.com/2009/12/15/lies-damned-lies-and-clash-of-the-dinosaurs/" rel="external">Matt’s initial blog post</a>. If we don’t take a stand, we are simply emboldening sloppy science communication. We should email, phone, or write to these companies and let them know that we are not happy with how science is being misrepresented. As a last resort one may consider taking legal action. While scientists give up many of their privileges once they sign a release form, slander is still slander, and as such is subject to legal action.<br /><br />Good science doesn’t need to be dressed up or distorted, most especially when we are talking about dinosaurs. While some may cringe at the very thought, scientists more than ever before need to become media-saavy. The media is ultimately interested in a great story and will go to extreme lengths to get it. The case of Matt is not new and their will be many more cases like it to come. Only by being more aware of how the media operates can scientists be equipped to deal with such future misrepresentations.<br /><br /><strong>Related reading</strong><br /><a href="https://svpow.wordpress.com/2009/12/15/lies-damned-lies-and-clash-of-the-dinosaurs/" rel="external">Lies, damned lies, and Clash of the Dinosaurs</a><br /><a href="https://svpow.wordpress.com/2009/12/17/clash-of-the-dinosaurs-dangerous-ltd-document-their-own-dishonest-editing/" rel="external">Clash of the Dinosaurs: Dangerous Ltd document their own dishonest editing</a><br /><a href="https://svpow.wordpress.com/2009/12/17/clash-of-the-dinosaurs-the-discovery-channel-steps-up/" rel="external">Clash of the Dinosaurs: The Discovery Channel steps up</a><br /><a href="https://scienceblogs.com/tetrapodzoology/2009/12/quote_mining_clash_of_the_dinosaurs.php" rel="external">A scientist is QUOTE MINED on a Discovery dinosaur documentary</a><br /><!-- AddThis Button BEGIN --><br /><body><script type="text/javascript">var addthis_pub="4a1c2d6a388b86af";</script><br /><a href="https://www.addthis.com/bookmark.php?v=20" onmouseover="return addthis_open(this, '', '[URL]', '[TITLE]')" onmouseout="addthis_close()" onclick="return addthis_sendto()"><img src="https://s7.addthis.com/static/btn/lg-share-en.gif" width="125" height="16" alt="Bookmark and Share" style="border:0"/></a><script type="text/javascript" src="https://s7.addthis.com/js/200/addthis_widget.js"></script><!-- AddThis Button END --></body><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-8184817661874111445?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0tag:blogger.com,1999:blog-2901919545584981466.post-23519490256553657852009-12-03T13:23:00.000-08:002010-03-21T13:26:11.065-07:00Irish Neandertals!This <a href="https://www.springerlink.com/content/l8847jx80k21g837/" rel="external">abstract</a> from a 1961 paper made me smile:<br /><br /><em><ul>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. </em><strong><em>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.</em></strong><em></ul><br /></em>Casey AE, Franklin RB. 1961. Cork-kerry Irish compared anthropometrically with 139 modern and ancient peoples. Irish Journal of Medical Science. 36 (9).<div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-2351949025655365785?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0tag:blogger.com,1999:blog-2901919545584981466.post-52386571694871632882009-11-21T13:04:00.000-08:002010-03-21T13:37:59.997-07:00One chin does not a modern human make<img class="imageStyle" alt="Guangxi chins" src="/files/guangxi-chins.jpg" width="431" height="141"/><br />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 <em>Homo sapiens</em> and archaic <em>Homo</em>.<br /><br />Wu Xinzhi of the Chinese Academy of Sciences had <a href="https://english.cas.cn/Ne/CASE/200911/t20091104_46676.shtml" rel="external">the following to say</a> about the find:<br /><em><ul>”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’”.</ul></em>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 <em>sensu stricto</em> versus ‘out of Africa’ <em>sensu stricto </em>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 <em>Homo</em> is still very much a debated issue.<br /><br />At this stage you may be wondering why there has been such furore over a chinned jaw. As long ago as 1775, Johann Friedrich Blumenbach <a href="https://books.google.com/books?id=7Y6NFaPxEswC&pg=PA300&lpg=PA300&dq=Blumenbach+chin&source=bl&ots=z2b1rEjw2a&sig=vm-hXzlQhDhet8f0H15U0PQ8kpw&hl=en&ei=ku4GS4byKIuh4Qbnh73UCw&sa=X&oi=book_result&ct=result&resnum=1&ved=0CAgQ6AEwAA#v=onepage&q=&f=false" rel="external">commented</a> on the uniqueness of the modern human chin:<br /><em><ul>In the animals there is scarcely a particular chin which can be considered as comparable to that of man: and in those men who, as is often said, seem to have something apish in their countenance, this generally resides in a deeply-retreated chin.</ul></em>The distinctive modern human chin develops through the combination of bone deposition on the inferior part of the jaw and resorption around the alveolar region. In other primates the entire jaw undergoes deposition. The modern human chin is characterised as having a central keel, with hollowed out depressions (known as mental fossae) to either side, together with a protruding inferior portion. This distended mental protuberance and lateral extremities make up the mental trigone, giving the chin the appearance of an inverted T. It is the combination of all these anatomical features that make up the prototypal modern chin. However, chins show great variability, with some modern humans not having any.<br /><br />This variability is also extends to earlier hominins. The Middle Pleistocene fossils from the Sima de los Huesos have been described as having chins, and even well-developed mental trigones. Among Pleistocene hominins, Neandertals appear to have the most divergent pattern from the modern configuration, universally lacking the inverted T and mental fossae. While it has been argued that the Neandertal mandibles from the Croatian site of Vindija show the development of incipient chins, this has not been borne out by later analyses.<br /><br />Some of the ‘modern’ Klasies River Mouth mandibles do not have developed mental trigones, midline keel or a thickening of the inferior margin. However, the modern designation of this material is controversial with these fossils showing a mosaic of both archaic and modern features. Similarly, the modern humans from Qafzeh show variable expression of the inverted T and mental fossae, with no indication of these features in the Skhūl specimens. The 700-800,000 year-old Tighenif mandibles show a surprisingly modern configuration complete with central keel, a thickened inferior portion, and the development of a triangular protuberance. The presence of a chin in these specimens could represent a synapomorphy with modern humans. <br /><br />Based on the archaeological record, it appears that modern humans left Africa some time around 100,000 years ago. Among the oldest undisputed modern human remains in China come from Zhoukoudian Cave at around 35,000 years BP. The possibly earlier fossil from Liujiang is marred with dating problems. In order for the Chinese scientists’ assertion to hold, it would require an even earlier exit from Africa or expansive gene flow between modern humans living in Africa and archaic humans in Asia; claims for which the evidence is currently lacking. Future analyses of the specimens will determine whether these chins have a truly modern form or whether the pattern is more like the non-homologous protruding inferior jaws seen in other archaic specimens. Alternatively, if these specimens end up being the result of convergent evolution it would raise questions about the functional significance of a chin. Finally, if these fossils show a pattern similar to the one seen in the Tighenif fossils it may suggest that they belong to the same clade.<br /><br /><br /><strong>References and further reading</strong><br />Ahern JC (1993). The Transitional Nature of the Late Neandertal Mandibles from Vindija Cave, Croatia. M.A. thesis. Department of Anthropology, Northern Illinois University.<br /><br />Blumenbach, JF (1978). The anthropological treatises of Johann Friedrich Blumenbach / translated and edited from the Latin, German, and French originals by Thomas Bendyshe. Boston : Longwood Press.<br /><br />Hawks, J (2009). I<a href="https://johnhawks.net/weblog/fossils/china/mulan-mandible-stone-2009.html" rel="external">t came from Guangxi</a>.<br /><br />McKenna, P (2009). <a href="https://www.newscientist.com/article/dn18093-chinese-challenge-to-out-of-africa-theory.html" rel="external">Chinese challenge to 'out of Africa' theory.</a> New Scientist.<br /><br />Rosas, A. (1995). Seventeen new mandibular specimens from the Atapuerca/Ibeas Middle Pleistocene hominids sample. J. hum. Evol. 28, 533–559.<br /><br />Schwartz JH, Tattersall I (2000). The human chin revisited: what is it and who has it? J Hum Evol 38:367-409.<br /><br />Schwartz JH, Tattersall I (2002) The Human Fossil Record, Vol. 1: Craniodental Morphology of Genus <em>Homo</em> (Europe) Wiley-Liss: New York.<br /><br />Stone R (2009). <a href="https://www.sciencemag.org/cgi/content/summary/326/5953/655-a" rel="external">Signs of Early Homo sapiens in China?</a> Science 326 (5953) p 655.<br /><!-- AddThis Button BEGIN --><br /><body><script type="text/javascript">var addthis_pub="4a1c2d6a388b86af";</script><br /><a href="https://www.addthis.com/bookmark.php?v=20" onmouseover="return addthis_open(this, '', '[URL]', '[TITLE]')" onmouseout="addthis_close()" onclick="return addthis_sendto()"><img src="https://s7.addthis.com/static/btn/lg-share-en.gif" width="125" height="16" alt="Bookmark and Share" style="border:0"/></a><script type="text/javascript" src="https://s7.addthis.com/js/200/addthis_widget.js"></script><!-- AddThis Button END --></body><br /><span style="font-size:9px; color:#666666;"> Above image: </span><span style="font-size:9px; color:#666666;"><a href="https://english.ivpp.cas.cn/" rel="external">Institute of Vertebrate Palaeontology and Palaeoanthropology, Chinese Academy of Sciences.</a></span><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-5238657169487163288?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0tag:blogger.com,1999:blog-2901919545584981466.post-66254066683370830362009-11-05T13:43:00.000-08:002010-03-21T13:37:58.912-07:00Full frontal hominins<div class="image-right"><a href="https://www.flickr.com/photos/arnybo/2353654486/" rel="external"><img class="imageStyle" alt="modern skull" src="/files/modern human.jpg" width="181" height="164"/></a></div>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 <em>Homo</em>, whose brain cases are positioned well behind their faces. <br /><br />The incredible brow ridges of <em>Homo erectus</em> is perhaps this species most salient physical feature. <div class="image-left"><a href="https://www.flickr.com/photos/missmareck/2194614896/" rel="external"><img class="imageStyle" alt="Homo erectus" src="/files/homo_erectus-2.jpg" width="205" height="170"/></a></div>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 <em>H. erectus</em>, 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.<br /><br />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 <em>H. erectus,</em> Neandertals have a more vertical and rounded forehead, with a less pronounced supraorbital torus.<br /><br />Modern humans have a vertical forehead, due to in no small part to the expansion of the front part of the brain. Unlike in other hominins, the frontal lobes sit directly above the orbits, negating the need for a supraorbital torus. Instead, we tend to have relatively lightly developed superciliary arches. In present day populations, large supraorbitals are generally seen in individuals that have both robust and narrow skulls. Supraorbital ridges can also occur in cases of neurodevelopmental disorders, such as microcephaly, in which case normal orbital size is combined with smaller cerebral size. The presence of a supraorbital torus in the hominin <em>Homo floresiensis</em> was one of the traits that some researchers used to suggest that these dwarf humans were in fact microcephalic <em>Homo sapiens</em>.<br /><br /><div class="image-right"><a href="/assets/basicranial_flexion.png" rel="shadowbox" title="basicranial flexion"><img class="imageStyle" alt="basicranial_flexion_thumb" src="/files/basicranial_flexion-small.png" width="230" height="233"/></a></div>Modern adult humans have the most flexed basicranium of any mammal. This is due largely to us having a more vertically oriented sphenoid bone. A more flexed cranial base repositions the face directly below the anterior cranial fossa, while a more extended cranial base results in greater facial prognathism. In turn, the combination of an extended cranial base and facial forwardness influences the development of the supraorbital region. Early modern human skulls, such as Skhūl V and Dar es-Soltan, have prominent brow ridges. The development of large supraorbitals in these specimens results from greater cranial base angulation. In this regard, the development of the supraorbital region in some early modern humans does not result from neuro-orbital disjunction like in archaic humans, but primarily because of their more extended cranial base.<br /><br />While much has been written about the non-metric variation of the frontal in hominins, there is little in the way of metric analyses, due to the bone's lack of cranial landmarks. Sheela Athreya recently carried out <a href="https://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6WJS-4XJVYW1-2&_user=10&_coverDate=10%2F29%2F2009&_rdoc=2&_fmt=high&_orig=browse&_srch=doc-info(%23toc%236886%239999%23999999999%2399999%23FLA%23display%23Articles)&_cdi=6886&_sort=d&_docanchor=&_ct=35&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=38f062b6f43a74db4e2a12980eec48e0" rel="external">a quantitative study </a>of the frontal bones of various Pleistocene hominins. She collected outlines along the sagittal and parasagittal planes of the bone. Based on her analyses, specimens were classified as either Early Pleistocene, <em>Homo erectus</em>, Middle Pleistocene, Neandertal or anatomically modern <em>Homo sapiens</em>.<br /><br />The highest classification accuracy was along the midsagittal plane, with a success rate of a mere 68%. In other words, using this technique almost one-third of specimens were misclassified. A well-seasoned palaeoanthropologist would have a much higher success rate using only non-metric traits. The key to identifying which species a particular frontal bone comes from involves looking at the totality of features along the entire length of the torus and surrounding bone. It is likely that if each of the curves were combined in a multivariate analysis they would have yielded a much higher classificatory success rate. Linear measurements along a curve only capture two dimensions of the frontal form, thereby losing a lot of information contained in the third dimension. A better approach would be to digitise a three-dimensional dense point cloud along the entire bone and to analyse the region using geometric morphometrics. However, such equipment is expensive and not available in most anthropology departments.<br /><br />Perhaps the most important outcome of this study was that it quantitatively confirmed some of the general characteristics of the frontal form of <em>Homo, </em>that have been previously described qualitatively. These include the fact that most of the variation in the frontal bone between Pleistocene groups is along the midsagittal plane. The study additionally found <em>Homo erectus </em>to differ from all other groups in the projection of the glabellar region. Finally, it identified modern humans as differing from all other groups in the curvature of the forehead, as well as the prominence of the lateral supraorbital torus. This confirms what many palaeoanthropologists have been saying for a long time – the lack of a supraorbital torus in modern humans is a uniquely derived feature.<br /><br /><br /><strong>References<br /></strong><br />Athreya, S. A comparative study of frontal bone morphology among Pleistocene hominin fossil groups, J Hum Evol (2009), doi:10.1016/j.jhevol.2009.09.003.<br /><br />Lahr, MM. The Evolution of Modern Human Diversity : A Study on Cranial Variation . Cambridge; New York : Cambridge University Press, 1996.<br /><br />Lieberman, Daniel E, Osbjorn M Pearson, and Kenneth M Mowbray. "Basicranial Influence on Overall Cranial Shape." Journal of Human Evolution 38 (2000): doi:10.1006/jhev.1999.0335.<br /><br />Martin RD, MacLarnon AM, Phillips JL, Dussebieux L, Williams PR, Dobyns WV. 2006a. Comment on ‘‘The brain of LB1, Homo floresiensis.’’ Science 312:999b.<br /><br />Trinkaus. Modern Human versus Neandertal Evolutionary Distinctiveness. Current Anthropology (2006) vol. 47 (4) pp. 597-620.<br /><br />Trinkaus. European early modern humans and the fate of the Neandertals. Proceedings of the National Academy of Sciences (2007) 104 (18) pp. 7367-7372.<br /><span style="font-size:9px; color:#666666;"><br />Above photos modified from originals by </span><span style="font-size:9px; color:#666666;"><a href="https://www.flickr.com/photos/missmareck/2194614896/" rel="external">missmareck</a></span><span style="font-size:9px; color:#666666;"> and </span><span style="font-size:9px; color:#666666;"><a href="https://www.flickr.com/photos/arnybo/2353654486/" rel="external">arnybo</a></span><span style="font-size:9px; color:#666666;"> under creative commons license.<br />Image of lateral dissected skull by </span><span style="font-size:9px; color:#666666;"><a href="https://dollinjune14.deviantart.com/art/Anatomic-study-16-104424924" rel="external">dollinjune14</a></span><span style="font-size:9px; color:#666666;">, via deviantART (modified from original).</span><br /><!-- AddThis Button BEGIN --><br /><body><script type="text/javascript">var addthis_pub="4a1c2d6a388b86af";</script><br /><a href="https://www.addthis.com/bookmark.php?v=20" onmouseover="return addthis_open(this, '', '[URL]', '[TITLE]')" onmouseout="addthis_close()" onclick="return addthis_sendto()"><img src="https://s7.addthis.com/static/btn/lg-share-en.gif" width="125" height="16" alt="Bookmark and Share" style="border:0"/></a><script type="text/javascript" src="https://s7.addthis.com/js/200/addthis_widget.js"></script><!-- AddThis Button END --></body><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-6625406668337083036?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0tag:blogger.com,1999:blog-2901919545584981466.post-46165940283577764402009-10-27T11:36:00.000-07:002010-03-21T13:37:57.850-07:00Did Neandertals and modern humans interbreed?<div class="image-right"><a href="https://www.flickr.com/photos/erix/142070879/" rel="external"><img class="imageStyle" alt="Neandertal" src="/files/neandertal.jpg" width="188" height="195"/></a></div>Ever since William King proposed the taxonomic designation <em>Homo neanderthalensis</em> 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.<br /><br /><div class="image-left"><a href="https://www.flickr.com/photos/kevinkemmerer/2807722862/" rel="external"><img class="imageStyle" alt="woman" src="/files/woman.jpg" width="141" height="196"/></a></div>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.<br /><br /><strong><em><br /></em></strong><span style="font-size:13px; font-weight:bold; "><em>The morphological evidence</em></span><strong><br /></strong><br />Palaeoanthropologists generally have little problem seperating Neandertals and modern humans based on their gross morphologies. However, some of the earliest modern humans from central Europe have traits that have been seen as evidence for continuity between them and Neandertals. These fossils, particularly those from Peştera cu Oase in Romania and Mladeč in the Czech Republic, have been touted as exemplars for modern-Neandertal admixture. These specimens show traits that are seen in high frequencies in Neandertals, such as bunning of the occipital and the presence of a suprainiac fossa.<br /><br />However, many researchers have questioned whether these traits are in fact distinctly Neandertal. For instance, the form of the occipital seems to be different in early Upper Palaeolithic populations, leading many to favour the term hemibun to describe the shape of the occipital in early Europeans. Lieberman and colleagues has gone as far as to suggest that the buns seen in these two groups are not homologous. Similarly, it has been argued that the shape of the suprainiac fossa is distinct in early modern Europeans compared to Neandertals.<br /><br />A palpable difficulty in assessing proposed Neandertal traits in early modern humans is that both groups shared similar niches and some traits may be the result of lifetime behavioural adaptations or convergent evolution. Indeed, the shared robustness of these early humans is likely due to the higher physical activities of these Late Pleistocene groups than during later period.<br /><br /><br /><span style="font-size:13px; font-weight:bold; "><em>The genetic evidence</em></span><strong><br /><br /></strong>Mitochondrial DNA (mtDNA) has some characteristics that make it ideal for analyses of ancient specimens. MtDNA is found in abundance – cells can have thousands of copies of mtDNA, while only containing two copies of nuclear DNA. Moreover, its structure and location within the cell make it more resistant to decay. All the studies of Neandertal mtDNA to date cluster outside the range for modern human mtDNA variation. However, the mitochondria contain only a small part of the total DNA that make up a genome. The possibility that Neandertal genes could show up somewhere else in the genome cannot be ruled out.<br /><br />The recent announcement by Svante Pääbo that he is sure that Neandertals and modern humans had sex is quite a bold pronouncement coming from a scientist. It raises the question of whether this ascertain is based on some hard evidence they found while sequencing the Neandertal genome. It is possible that if there was some Neandertal genes passed on to the first moderns in Europe, they could have got eliminated from the subsequent gene pool as population sizes fluctuated during the more severe climatic episodes. A more likely scenario is that Pääbo's team found evidence of modern introgression in the Neandertal genome. In all likelihood the incoming modern humans were more numerous than the Neandertals, thereby absorbing the endemic populations through genetic swamping.<br /><br /><br /><span style="font-size:13px; font-weight:bold; ">References</span><br /><br />Caspari RE. 1991. The evolution of the posterior cranial vault in the central European Upper Pleistocene. PhD dissertation. Ann Arbor, MI: University of Michigan.<br /><br />King, W., 1864. The reputed fossil man of Neanderthal. Quarterly Journal of Science 1, 88–97.<br /><br />Krings et al. 1997. Neandertal DNA sequences and the origin of modern humans. Cell vol. 90 (1) pp. 19-30.<br /><br />Krings M, Capelli C, Tschentscher F, et al. 2000. A view of Neandertal genetic diversity. Nat Genet 26, 144–146.<br /><br />Lieberman et al. 2000. Basicranial influence on overall cranial shape. J. Hum. Evol. vol. 38 (2) pp. 291-315.<br /><br />Nara MT. 1994. Etude de la variabilité de certainscaractères métriques et morphologiques des Néandertaliens. Bordeaux: Thèse de Docteur.<br /><br />Pääbo S, Poinar H, Serre D, et al. 2004. Genetic analyses from ancient DNA. Ann Rev Genet 38, 645–679.<br /><!-- AddThis Button BEGIN --><br /><body><script type="text/javascript">var addthis_pub="4a1c2d6a388b86af";</script><br /><a href="https://www.addthis.com/bookmark.php?v=20" onmouseover="return addthis_open(this, '', '[URL]', '[TITLE]')" onmouseout="addthis_close()" onclick="return addthis_sendto()"><img src="https://s7.addthis.com/static/btn/lg-share-en.gif" width="125" height="16" alt="Bookmark and Share" style="border:0"/></a><script type="text/javascript" src="https://s7.addthis.com/js/200/addthis_widget.js"></script><!-- AddThis Button END --></body><br /><span style="font-size:9px; color:#666666;">Above photos modified from originals by </span><span style="font-size:9px; color:#666666;"><a href="https://www.flickr.com/photos/erix/" rel="external">erix!</a></span><span style="font-size:9px; color:#666666;"> and </span><span style="font-size:9px; color:#666666;"><a href="https://www.flickr.com/photos/kevinkemmerer/" rel="external">fangleman</a></span><span style="font-size:9px; color:#666666;"> under creative commons license.</span><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-4616594028357776440?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0tag:blogger.com,1999:blog-2901919545584981466.post-59058725680954926432009-10-17T09:57:00.000-07:002010-03-21T13:26:05.839-07:00John Hawks on ArdipithecusRazib Khan of the <a href="https://scienceblogs.com/gnxp/" rel="external">Gene Expression blog</a> interviews <a href="https://johnhawks.net/weblog" rel="external">John Hawks</a> regarding the significance of <em>Ardipithecus ramidus</em>.<br /><br /><embed type="application/x-shockwave-flash" src="https://static.bloggingheads.tv/maulik/offsite/offsite_flvplayer.swf" flashvars="playlist=http%3A%2F%2Fbloggingheads%2Etv%2Fdiavlogs%2Fliveplayer%2Dplaylist%2F23155%2F00%3A00%2F65%3A13" height="288" width="380"></embed><br /><!-- AddThis Button BEGIN --><br /><body><script type="text/javascript">var addthis_pub="4a1c2d6a388b86af";</script><br /><a href="https://www.addthis.com/bookmark.php?v=20" onmouseover="return addthis_open(this, '', '[URL]', '[TITLE]')" onmouseout="addthis_close()" onclick="return addthis_sendto()"><img src="https://s7.addthis.com/static/btn/lg-share-en.gif" width="125" height="16" alt="Bookmark and Share" style="border:0"/></a><script type="text/javascript" src="https://s7.addthis.com/js/200/addthis_widget.js"></script><!-- AddThis Button END --></body><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-5905872568095492643?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0tag:blogger.com,1999:blog-2901919545584981466.post-34183908483201243902009-10-10T11:45:00.000-07:002010-03-21T13:37:54.141-07:00Homo heidelbergensis and the muddle in the middle<div class="image-left"><img class="imageStyle" alt="Craneo_5" src="/files/craneo_5.jpg" width="145" height="169"/></div>Michael Balter <a href="https://www.sciencemag.org/cgi/content/summary/326/5950/224" rel="external">reports for </a><em><a href="https://www.sciencemag.org/cgi/content/summary/326/5950/224" rel="external">Science</a></em> on a recent conference held in Gibraltar entitled <em>Human Evolution 150 Years After Darwin </em>[1]<em>. </em>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 <em>The Descent of Man </em>[2].<br /><br />At the conference, much attention was focused on the Middle Pleistocene "muddle in the middle" [3], particularly the role of <em>Homo heidelbergensis</em> in hominin evolution. While <em>H. heidelbergensis </em>possesses both archaic and derived traits intermediate between <em>H. erectus </em>and later members of the <em>Homo </em>genus, it lacks uniquely derived traits or autapomorphies, which are a prerequisite for defining a species. <br /><br /><em>H. heidelbergensis</em> 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 <em>H. heidelbergensis</em> 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.<br /><br />Another scenario views both the European and African <em>H. heidelbergensis</em> as a single species, and the last common ancestor of both Neandertals and modern humans. Alternatively, <em>H. heidelbergensis</em> could have become isolated in Europe and evolved into Neandertals, while the African populations led to modern humans.<br /><br />During the conference, Ian Tattersall noted that while the accretion model explains some of the variation in the Middle Pleistocene, it cannot account for some outliers, such as the 28 or so specimens that have been recovered from the Sima de los Huesos in Atapuerca, Spain. Tattersall is not the first author to call the accretion model into question [7]. Recent dates have placed the Sima fossils at just over half-a-million years old. Based on the dissimilarity between these fossils and the penicontemporaneous <em>H. heidelbergensis </em>from the rest of Europe, Tattersall proposes that two hominin lineages coexisted in Europe before the arrival of <em>H. sapiens</em>. He suggests that one line (which may include the Sima specimens) led to the Neandertals, while the branch which included <em>H. heidelbergensis</em> went extinct. If Tattersall is correct it would mean that the Sima fossils, which are currently classified as <em>H. heidelbergensis</em>, must be designated another name.<br /><br />Hublin is to his guns and doesn't see any need to reclassify the Sima material. He goes as far as to suggest binning the species name <em>H. heidelbergensis</em> altogether and instead reassigning all these Middle Pleistocene fossils as <em>H. neanderthalensis</em>. Whatever the outcome is in this debate, it appears that hominin evolution in the Middle Pleistocene is more complex than we have previously suspected.<br /><br /><strong>References<br /><br /></strong>1. Balter M. New work may complicate history of Neandertals and H. sapiens. Science 2009; 326:224-5.<br /><br />2. Darwin C. The descent of man, and selection in relation to sex. New York, A. L. Burt; 1874.<br /><br />3. Butzer KW, Isaac GL, International Congress of Anthropological and Ethnological Sciences 9C1. After the Australopithecines : stratigraphy, ecology, and culture, change in the Middle Pleistocene . The Hague : Mouton ; Chicago : distributed in the USA and Canada by Aldine; 1976.<br /><br />4. Hublin. Paleogeography, and the evolution of the Neandertals. In: Akazawa, Aoki, Bar-Yosef, Eds. Neandertals and Modern Humans in Western Asia. New York: Plenum Press; 1998:295-310.<br /><br />5. Hublin. Climatic Changes, Paleogeography, and the Evolution of the Neandertals. In: Akazawa, Aoki, Bar-Yosef, Eds. Neandertals and Modern Humans in Western Asia. New York: Plenum Press; 1998:295-310.<br /><br />6. Martinón-Torres M, Bastir M, Bermúdez de Castro JM, Gómez A, Sarmiento S, Muela A, Arsuaga JL. Hominin lower second premolar morphology: evolutionary inferences through geometric morphometric analysis. J Hum Evol 2006; 50:523-33.<br /><br />7. Hawks JD, Wolpoff MH. The accretion model of Neandertal evolution. Evolution 2001; 55:1474-85.<br /><!-- AddThis Button BEGIN --><br /><body><script type="text/javascript">var addthis_pub="4a1c2d6a388b86af";</script><br /><a href="https://www.addthis.com/bookmark.php?v=20" onmouseover="return addthis_open(this, '', '[URL]', '[TITLE]')" onmouseout="addthis_close()" onclick="return addthis_sendto()"><img src="https://s7.addthis.com/static/btn/lg-share-en.gif" width="125" height="16" alt="Bookmark and Share" style="border:0"/></a><script type="text/javascript" src="https://s7.addthis.com/js/200/addthis_widget.js"></script><!-- AddThis Button END --></body><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-3418390848320124390?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0tag:blogger.com,1999:blog-2901919545584981466.post-2696656328003868162009-10-02T06:04:00.000-07:002010-03-21T13:37:53.069-07:00The pelvis of Ardipithecus ramidus<img class="imageStyle" alt="Untitled-p13643-5" src="/files/untitled-p13643-5.jpg" width="480" height="260"/><br /><br />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 <em>Ardipithecus ramidus</em> fossil remains give us a glimpse of what the one of the earliest members of the hominin lineage looked like. While the feet of <em>Ar. ramidus</em> show that it was still adapted to life in the trees, the pelvis shows significant adaptations to walking upright on two legs. <br /><br />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 <em>Ar. ramidus</em> 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.<br /><br />However, the ischium is quite primitive compared to the ilia, likely to accommodate the large hindlimb musculature required for tree climbing. The two best preserved australopithicine pelves, AL 288-1 and Sts 14, both have short ischia, like those seen in modern humans. The preserved portion of the ischial ramus in <em>Ar. ramidus</em> is significantly larger than that found in any of the Australopithecines. A long ischium creates a greater moment arm suggesting that <em>Ar. ramidus</em> had relatively powerful hamstrings, a trait that is common in tree-dwelling primates.<br /><br />The configuration of the ARA-VP-6/500 pelvis suggests that lower lumbars were probably posteriorly positioned, allowing for lordosis of the spine. A reduction in iliac height would have further facilitated lordosis. Lordosis positions the spine to a more forward position, so that it directly overlies the hips during erect posture. Lower spinal lordosis would have allowed the full extension of the hips and knee during extended bipedal locomotion.<br /><br /><em>Ar. ramidus</em> was quite capable of bipedal locomotion, as attested to by the morphology of its pelvis and foot. However, its large thigh muscles and its prehensile big toe show that it was still very much adapted to arboreal life. <em>Ar. ramidus</em> shares arboreal adaptations that were probably present in the human-chimp last common ancestor, as well as bipedal adaptations that are so characteristic of hominins. <em>Ar. ramidus</em> appears to have been an arboreal ape with bipedal adaptations, rather than a biped with arboreal adaptations. It is not until almost half-a-million years later, with the arrival of <em>Australopithecus afarensis</em>, that we find a truly habitual bipedal hominin.<br /><!-- AddThis Button BEGIN --><br /><body><script type="text/javascript">var addthis_pub="4a1c2d6a388b86af";</script><br /><a href="https://www.addthis.com/bookmark.php?v=20" onmouseover="return addthis_open(this, '', '[URL]', '[TITLE]')" onmouseout="addthis_close()" onclick="return addthis_sendto()"><img src="https://s7.addthis.com/static/btn/lg-share-en.gif" width="125" height="16" alt="Bookmark and Share" style="border:0"/></a><script type="text/javascript" src="https://s7.addthis.com/js/200/addthis_widget.js"></script><!-- AddThis Button END --></body><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-269665632800386816?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0tag:blogger.com,1999:blog-2901919545584981466.post-52828354889382375622009-09-09T04:55:00.000-07:002010-03-21T13:37:50.902-07:00Four Stone Hearth #75<a href="https://fourstonehearth.net/" rel="external"><img class="imageStyle" alt="four stone hearth" src="/files/header1.jpg" width="480" height="60"/></a><br /><strong><br /></strong>Welcome to Four Stone Hearth number 75. <a href="https://fourstonehearth.net/" rel="external">Four Stone Hearth</a> 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 <a href="mailto:arador[AT]algonet.se" rel="external">Martin Rundkvist</a>. The next issue will be hosted at the <a href="https://afarensis99.wordpress.com/" rel="external">Afarensis blog</a> on 23 September. So without further preamble, let's get on with the show.<br /><strong><br /></strong><span style="font-size:14px; font-weight:bold; "><u>Archaeology</u></span><br />Martin Rundkvist talks about <a href="https://scienceblogs.com/aardvarchaeology/2009/09/a_touch_of_pitted_ware.php" rel="external">his experience</a> digging at a Middle Neolithic coastal site in Sweden. Among the finds were small potsherds and a fine example of Pitted Ware.<br /><br /><a href="https://www.nature.com/nature/journal/v461/n7260/full/nature08214.html" rel="external">A recent article</a> in the journal <em>Nature </em>reports on the "oldest handaxes" in Europe. <a href="https://johnhawks.net/weblog/reviews/archaeology/lower/acheulean-early-spain-2009.html" rel="external">John Hawks</a> 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.<br /><br /><br /><span style="font-size:14px; font-weight:bold; "><u>Biological anthropology</u></span><span style="font-size:13px; font-weight:bold; "><br /></span>Anybody who has been following anthropology news for the past few weeks will be well aware of the spirited reaction that <a href="https://www.scientificamerican.com/article.cfm?id=fossils-for-all" rel="external">a recent editorial</a> in Scientific American generated. The article calls for the adoption of more open practices with regard to accessing human fossils. I have written <a href="/files/fossil_and_data_access.html" rel="external">a piece</a> where I give my own take on the issue.<strong><br /></strong><br /><a href="https://www.somatosphere.net/2009/08/jonathan-marks-why-i-am-not-scientist.html" rel="external">Matthew Wolf-Meyer</a> reviews Jonathan Marks' latest book "Why I am not a scientist". Jonathan Marks is a controversial anthropologist, who sticks to his guns in this, his latest work. Ever thought provoking, Marks is bound to stir up some debate among anthropologists and scientists alike.<br /><br />There has been a lot of debate regarding whether Central European farmers were the descendants of indigenous hunter-gathers or the result of a demic diffusion from the southeast. <a href="https://dienekes.blogspot.com/2009/09/central-european-farmers-not-descended.html" rel="external">Dienkes</a> reports on a new study which suggests that Central European farmers were in fact probably not descended from local hunter-gatherer groups.<br /><br /><a href="https://bridgesandtangents.wordpress.com/2009/09/08/neandertals/" rel="external">Stephen Wang</a> asks the age old question of how similar Neandertals were to us and how they thought about the world.<br /><br /><br /><span style="font-size:14px; font-weight:bold; "><u>Linguistic anthropology</u></span><br /><a href="https://innovationinteaching.org/blog/2009/08/20/anthropology-and-language-teachingsome-lessons/" rel="external">The Innovation in Teaching</a> blog explains the concept of a “focused gathering”, a term coined by anthropologist Clifford Geertz. The post goes on to discuss how this concept helps us better think about classroom dynamics.<br /><br /><br /><span style="font-size:14px; font-weight:bold; "><u>Socio-cultural anthropology</u></span><br />Over at Neuroanthropology, Daniel Lende has<a href="https://neuroanthropology.net/2009/08/25/funerals-and-food-coping-in-rural-lesotho/" rel="external"> a revealing piece</a> which looks at food crises in Lesotho and the role funerals play in coping with these food shortages. In <a href="https://neuroanthropology.net/2009/09/06/sex-lies-and-irb-tape-netporn-to-surveyfail/" rel="external">another post</a> Daniel takes on the recent "research" by researchers Ogi Ogas and Sai Gaddam, which is plagued by poor methodologies and a pseudoscientific approach to neuroscience. <a href="https://neuroanthropology.net/2009/09/07/surveyfail-redax-downey-adds-to-lende/" rel="external">Greg Downey</a> follows this up with his own take on some of the methodological flaws of the investigators, principally their inflexibility in the face of contradictory evidence.<br /><br /><a href="https://savageminds.org/2009/09/08/anthropology-internet-addiction-and-care/" rel="external">Rex over at the Savage Minds blog</a> suggests that the real question anthropologists should ask regarding internet addiction is not whether it exists but rather <em>"how and in what forms do preexisting cultural structures predispose people to think something is true?"</em><br /><br />Greg Laden debunks the fallacy that <a href="https://scienceblogs.com/gregladen/2009/09/culture_overrides_biology_anot.php?utm_source=combinedfeed&utm_medium=rss" rel="external">culture overrides biology</a>. This part of a larger series on the common misperceptions that people have regarding biology.<br /><br />Idris Mootee thinks that <a href="https://mootee.typepad.com/innovation_playground/2009/08/good-industrial-designers-also-need-to-be-cultural-anthropologists-.html" rel="external">industrial designers need to think like cultural anthropologists</a>. He uses the example of how different cultures adopt their own particular posture while sitting. By being aware of this, designers can better accommodate the needs of the end user. <a href="https://culturematters.wordpress.com/2009/09/06/design-thinking/" rel="external">Joana Breidenbach of the Culture Matters blog is of a similar opinion</a>:<br /><br /><span style="font:14px Georgia, serif; font-weight:bold; font-weight:bold; "><em><ul></em></span><span style="font:13px Georgia, serif; font-weight:bold; font-weight:bold; "><em>"Design thinking has many overlaps with the anthropological approach, such as starting out with as little preconceived ideas about the research topic as possible and gaining an empathetic understanding through immersion during fieldwork."</em></span><span style="font:14px Georgia, serif; font-weight:bold; font-weight:bold; "><em></ul></em></span><br /><a href="https://www.bukisa.com/articles/144148_celtic-deities-in-archaeology" rel="external">Lian</a> explores the the archaeology of the worship of Celtic deities in Roman Britain.<br /><br /><a href="https://www.antropologi.info/blog/anthropology/2005/title_24" rel="external">Lorenz at the antropologi blog reviews</a> Thomas Hylland Eriksen's new book "Engaging Anthropology". In it, he addresses the question of why anthropologists fail to engage the general public. In <a href="https://www.timeshighereducation.co.uk/story.asp?storycode=407993" rel="external">a similar piece</a> that appeared in Times Higher Education, anthropologist Nancy Scheper-Hughes asserts that part of the problem may lie with universities:<br /><br /><span style="font:13px Georgia, serif; font-weight:bold; font-weight:bold; "><em><ul>"Scholars who want to reach diverse publics - through popular writing, speaking or participating in social activism - are not only under-rewarded by their universities, they are often penalised for 'dumbing down' anthropological thinking, cutting social theory into 'soundbites', 'vulgarising' anthropology, sacrificing academic standards or (in the US) for playing to the anti-intellectual, illiberal American popular classes."</ul></em></span><br /><a href="https://annasbones.com/2009/09/07/survival-of-the-trendiest/" rel="external">Anna Barros shows how trends are subject to selection</a>. She demonstrates how memes can be transmitted from person to person and how they respond to selection pressures.<br /><br /><br /><span style="font-size:14px; font-weight:bold; "><u>One more thing…</u></span><br />Each of the four fields of anthropology can offer us a glimpse into our past. Perhaps more importantly, they can take us on a journey and show us the steps which got us to where we are today. Photography offers yet another way of archiving the past. To use the clichéd metaphor – photographs are moments frozen in time. A <a href="https://www.flickr.com/photos/jasonepowell/sets/72157613841045343/comments/" rel="external">Flickr photostream</a> by <a href="https://www.flickr.com/photos/jasonepowell/" rel="external">Jason Powell</a> wonderfully bridges the gap between the past and the present, through the medium of photography. Enjoy!<br /><br /><object width="400" height="300"> <param name="flashvars" value="offsite=true&lang=en-us&page_show_url=%2Fphotos%2Fjasonepowell%2Fsets%2F72157613841045343%2Fshow%2Fwith%2F3809672913%2F&page_show_back_url=%2Fphotos%2Fjasonepowell%2Fsets%2F72157613841045343%2Fwith%2F3809672913%2F&set_id=72157613841045343&jump_to=3809672913"></param> <param name="movie" value="https://www.flickr.com/apps/slideshow/show.swf?v=71649"></param> <param name="allowFullScreen" value="true"></param><embed type="application/x-shockwave-flash" src="https://www.flickr.com/apps/slideshow/show.swf?v=71649" allowFullScreen="true" flashvars="offsite=true&lang=en-us&page_show_url=%2Fphotos%2Fjasonepowell%2Fsets%2F72157613841045343%2Fshow%2Fwith%2F3809672913%2F&page_show_back_url=%2Fphotos%2Fjasonepowell%2Fsets%2F72157613841045343%2Fwith%2F3809672913%2F&set_id=72157613841045343&jump_to=3809672913" width="400" height="300"></embed></object></p><br /><!-- AddThis Button BEGIN --><br /><body><script type="text/javascript">var addthis_pub="4a1c2d6a388b86af";</script><br /><a href="https://www.addthis.com/bookmark.php?v=20" onmouseover="return addthis_open(this, '', '[URL]', '[TITLE]')" onmouseout="addthis_close()" onclick="return addthis_sendto()"><img src="https://s7.addthis.com/static/btn/lg-share-en.gif" width="125" height="16" alt="Bookmark and Share" style="border:0"/></a><script type="text/javascript" src="https://s7.addthis.com/js/200/addthis_widget.js"></script><!-- AddThis Button END --></body><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-5282835488938237562?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0tag:blogger.com,1999:blog-2901919545584981466.post-29545897409093850102009-09-08T13:50:00.000-07:002010-03-21T13:37:49.375-07:00Fossil and data access in palaeoanthropology<div class="image-right"><a href="https://www.flickr.com/photos/12739382@N04/3607882912/" rel="external"><img class="imageStyle" alt="skull crossbows" src="/files/3607882912_b8b9b64756_m.jpg" width="111" height="111"/></a></div><a href="https://www.scientificamerican.com/article.cfm?id=fossils-for-all" rel="external">A recent article in Scientific American</a> 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 <a href="https://www.sciencemag.org/cgi/content/abstract/186/4167/892" rel="external">article</a> Stephen Jay Gould and David Pilbeam wrote for <em>Science</em>:<em><br /></em><em><br /></em><span style="font:12px Georgia, serif; font-weight:bold; font-weight:bold; "><ul></span><span style="font:13px Georgia, serif; font-weight:bold; font-weight:bold; "><em>"Human paleontology shares a peculiar trait with such disparate subjects as theology and extraterrestrial biology: it contains more practitioners than objects for study."</em></span><span style="font:12px Georgia, serif; font-weight:bold; font-weight:bold; "><em><br /></em></span><p style="text-align:right;"><span style="font:13px Georgia, serif; font-weight:bold; font-weight:bold; ">– Stephan J. Gould and David Pilbeam</span><span style="font:12px Georgia, serif; font-weight:bold; font-weight:bold; "></ul></span><br />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 <em>du jour,</em> 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.<br /><br />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 unenviable 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.<br /><br />Ancient fossils usually come out of the ground highly fragmented and in a poor state of preservation. Much time is required to clean, preserve and reconstruct them before conducting a phylogenetic analysis. While many people have focused on the fact that certain specimens have taken an exhorbitant amount of time to describe, thus holding up the process of peer validation, it must also be kept in mind that these represent only a small fraction of the total human fossil record. While it of the utmost importance to make fossils available to outside investigators in a timely fashion, it is perhaps not the most fruitful or constructive area in which to be directing our attention. <br /><br />Conflicts arise between researchers who want to access fossil material and curators who are genuinely concerned about the wear and tear that these fossils have endured through repeated handling. Curators will often direct researchers to others who have already measured the material in question, to avoid the redundant repetition of measurements. It is often at this point that researchers can come up against a brick wall, with peers who are unwilling to relinquish their valued data. Like the fossils themselves, unique data is a precious commodity and alas is necessary for publication. For good or for ill, peer-reviewed publications are placed in high regard in the anthropological world. Its role when it comes to job-seeking or tenure cannot be underestimated. An incredible amount of data has been collected through the years on ancient human remains but they are rarely put in the public domain. A noteworthy exception is the data on some 3,000 skulls from 17 worldwide populations, measured and made freely available by the eminent anthropologist <a href="https://books.nap.edu/html/biomems/whowells.pdf" rel="external">William W. Howells</a> (pdf file). The Howells' dataset is perhaps that man's most lasting legacy, at least in the sheer number of times his data have been used and referenced. Similarly, we need to place great value on other researchers who make their data available and this should be taken into consideration in matters of career advancement. At a minimum, the sharing of data should be deemed equivalent to research publication.<br /><br />Positive steps have been taken in the ensure more data is made available. The US <a href="https://www.nsf.gov/" rel="self">National Science Foundation</a> encourage applicants to make provisions to make data available after the research has been completed. The NSF <a href="https://www.nsf.gov/pubs/2001/gc101/gc101rev1.pdf" rel="external">states that</a>:<br /><br /><em><ul>It expects investigators to share with other researchers, at no more than incremental cost and within a reasonable time, the data, samples, physical collections and other supporting materials created or gathered in the course of the work.</ul></em><br />Anthropologists who fail to comply with these recommendations may have subsequent grant proposals turned down on these grounds. There is an ever-growing number of high quality casts and 3D images of fossils becoming available. Taphonomic processes may deform the fossilised bone and filling in gaps has often required a liberal amount of guesswork. 3D images often allow for better reconstructions of the original specimens, due to the ability to interpolate absent regions and more readily pinpoint and correct deformation. Research centres have woken up to the fact that collaborative projects tend to have a greater synergy due to their symbiotic nature. For palaeoanthropology to become a truly open discipline, it will not only need researchers to be more freehanded with their data, but will require funding agencies, universities and research centres to incentivise such actions.<br /><strong><br />Related reading<br /></strong><a href="https://johnhawks.net/weblog/topics/meta/scientific-american-data-access-2009.html" rel="external">Fossil access editorial @ John Hawks weblog.</a><br /><br /><a href="https://anthropology.net/2009/08/25/science-suffers-from-the-idiots-at-scientific-american/" rel="external">Science Suffers From The Idiots At Scientific American @ Anthropology.net.</a><br /><br /><a href="https://zinjanthropus.wordpress.com/2009/09/06/take-your-time/" rel="external">Take your time @ A Primate of Modern Aspect.</a><br /><br />Delson et al. Databases, data access, and data sharing in paleoanthropology: First steps. Evol. Anthropol. (2007) vol. 16 (5).<br /><strong><br /></strong>Gibbons. Glasnost for Hominids: Seeking Access to Fossils. Science (2002) vol. 297 pp. 1464-1468.<br /><br />Mafart. Human fossils and paleoanthropologists: a complex relation. Journal of Anthropological Sciences (2008) vol. 86 pp. 201-204.<br /><br />Pilbeam and Gould. Size and Scaling in Human Evolution. Science (1974) vol. 186 ( 4167), 892-901.<br /><br />Tattersall and Schwartz. Is paleoanthropology science? Naming new fossils and control of access to them. Anat Rec (2002) vol. 269 (6) pp. 239-41.<br /><!-- AddThis Button BEGIN --><br /><body><script type="text/javascript">var addthis_pub="4a1c2d6a388b86af";</script><br /><a href="https://www.addthis.com/bookmark.php?v=20" onmouseover="return addthis_open(this, '', '[URL]', '[TITLE]')" onmouseout="addthis_close()" onclick="return addthis_sendto()"><img src="https://s7.addthis.com/static/btn/lg-share-en.gif" width="125" height="16" alt="Bookmark and Share" style="border:0"/></a><script type="text/javascript" src="https://s7.addthis.com/js/200/addthis_widget.js"></script><!-- AddThis Button END --></body><br /></p><p style="text-align:left;"><span style="font-size:9px; color:#666666;">Above photo by </span><span style="font-size:9px; color:#666666;"><a href="https://www.flickr.com/photos/12739382@N04/" rel="external">Simon Strandgaard</a></span><span style="font-size:9px; color:#666666;"> under creative commons license.</span></p><div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-2954589740909385010?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0tag:blogger.com,1999:blog-2901919545584981466.post-77654368432943942682009-08-27T03:11:00.000-07:002010-03-21T13:25:59.598-07:00Anthro blog carnival: Four Stone Hearth 74The 74th <a href="https://www.fourstonehearth.net/" rel="self">Four Stone Hearth</a> anthropology blog carnival is available over at Adam Henne’s <a href="https://adamhenne.wordpress.com/2009/08/26/four-stone-hearth-74/" rel="external">Natures/Cultures</a> 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 <a href="mailto:arador[AT]algonet.se" rel="self">Martin Rundkvist</a> or <a href="mailto:adhominin[AT]me.com" rel="self">me</a> (be sure to replace [AT] with @ in the email addresses).<div class="blogger-post-footer"><img width='1' height='1' src='https://blogger.googleusercontent.com/tracker/2901919545584981466-7765436843294394268?l=adhominin.blogspot.com' alt='' /></div>Ciaránhttps://www.blogger.com/profile/07838368649776858125noreply@blogger.com0