The feeding biomechanics and dietary ecology of Australopithecus africanus
In today's PNAS, The feeding biomechanics and dietary ecology of Australopithecus africanus:
The African Plio-Pleistocene hominins known as australopiths evolved a distinctive craniofacial morphology that traditionally has been viewed as a dietary adaptation for feeding on either small, hard objects or on large volumes of food. A historically influential interpretation of this morphology hypothesizes that loads applied to the premolars during feeding had a profound influence on the evolution of australopith craniofacial form.
Here, we test this hypothesis using finite element analysis in conjunction with comparative, imaging, and experimental methods. We find that the facial skeleton of the Australopithecus type species, A. africanus, is well suited to withstand premolar loads. However, we suggest that the mastication of either small objects or large volumes of food is unlikely to fully explain the evolution of facial form in this species.
Rather, key aspects of australopith craniofacial morphology are more likely to be related to the ingestion and initial preparation of large, mechanically protected food objects like large nuts and seeds. These foods may have broadened the diet of these hominins, possibly by being critical resources that australopiths relied on during periods when their preferred dietary items were in short supply.
Our analysis reconciles apparent discrepancies between dietary reconstructions based on biomechanics, tooth morphology, and dental microwear.
Wednesday Wiki: The Bone Wars
The Bone Wars occurred during a period of intense fossil speculation and discovery during the Gilded Age of American history, marked by a heated rivalry between Edward Drinker Cope (of the Academy of Natural Sciences in Philadelphia) and Othniel Charles Marsh (of the Peabody Museum of Natural History at Yale). Each of the two paleontologists used underhanded methods to try to out-compete the other in the field, resorting to bribery, theft, and destruction of bones. Each scientist also attacked the other in scientific publications, seeking to ruin his credibility and have his funding cut off.
Darwin’s impact on our place in the world
As part of the 150th anniversary celebrations of a certain Charles Darwin, Radio New Zealand is getting a whole bunch of New Zealand scientists to give public lectures about Darwin's impact on our place in the world. They're recording them, broadcasting them over the radio, and you can listen to them on the internet here (the first two are online already).
Lecture 1 - Darwin and the Evolution of an Idea (Professor Lloyd Spencer Davis, University of Otago)
In the last 2000 years there has been one idea, above all else, that has altered the way we view the world and our place in it. That idea is evolution by natural selection and the originator of the idea was Charles Darwin
Lecture 2 - The Evolution of Biological Complexity (Professor Paul Rainey FRSNZ, Massey University).
Professor Rainey paints a picture of life's evolution from the perspective of major evolutionary transitions, including that from solitary organisms to societies.
Lecture 3. The Principle of Evolution: Absolute Simplicity (Professor David Penny CNZM FRSNZ, Research Director, Allan Wilson Centre for Molecular Ecology and Evolution, Massey University)
Can we find anything in biology that is not understandable, or not explainable, by the things we can observe and measure in the present? Evolution is, by far, the simplest possible way of understanding ourselves, our past, and our future.
Lecture 4. The fossil record (Professor Alan Cooper, Director, Australian Centre for Ancient DNA, The University of Adelaide)
How should we interpret what the fossil record tells us about evolution - both in general, and with regard to how New Zealand has ended up as it is today?
5. Evolutionary Psychology (Professor Russell Gray, The University of Auckland)
Attempts to explain human behaviour in evolutionary terms have a mixed history. Today, crude social Darwinian and socio-biological explanations are increasingly being replaced by richer, more complex theories.
6. The Storytelling Ape: Evolution, Art, Story, Culture (Professor Brian Boyd, The University of Auckland)
Brian Boyd will focus on art, perhaps the feature of human behavior that might seem to have least to do with a struggle for existence. Can biology explain why art (music, dance, visual art, storytelling and verse) is a human universal? Why do we so compulsively invent and engage with stories we know to be untrue?
Berger responds to Nature’s criticism
Lee Berger defends himself against the attack on him by Nature (which we mentioned a few days ago):
In fact, it is Mr. Dalton’s attempts to find a story where there was none that may have done damage to our ability to conduct research on human remains on Palau. We who do field research are very much aware of the sensitivities and rights of indigenous people - and respect them. Mr. Dalton’s inappropriate stirring of these emotions – deliberately and despite clear evidence that my team and I had conducted ourselves in an appropriate and legal manner is quite frankly reprehensible.
Concerning his utilization of the wording of some ad campaign made by a media company that is promoting a yet to be made television show, and calling these planned popular television science shows “other areas of his (my) research”, well, this is frankly contemptible. Those planned shows – which have nothing in fact to do with my own scientific research – are meant to be fun and educational. That is all, and Dalton is aware of this as well.
The rest of his response is on Anthropology.net
Palau bones: Caught between science and entertainment
Today's Nature covers the controversy about the recent paper Small-bodied humans from Palau, Micronesia by Berger et al. Last month, Berger and colleagues claimed that they'd found a collection of small bodied humans dating back between 940 and 2890 years (cal bp) in a burial cave in Palau:
Preliminary sampling of two burial caves in Palau, Micronesia has produced the remains of small-bodied recent H. sapiens, possibly representing a case of insular dwarfing. Individuals in this sample exhibit, in addition to small body size, reduction of the absolute size of the face, distinct supraorbital tori (in some individuals), a weakly developed mental eminence, relatively large dental dimensions, and dental dysplasias and agenesis.
Some of these features may be considered primitive for the genus Homo (or trending towards the primitive condition), thus the human fossils from Palau may provide important insights into the relationship between small body size and the expression of morphological features generally considered to be taxonomically diagnostic in our genus.
Given the scarcity of skeletal samples of small-bodied modern humans, and their importance for resolving taxonomic and phylogenetic issues in genus Homo paleontology, we provide here a brief description of the more salient specimens and a preliminary analysis of the material relative to small-bodied modern humans and to the holotype specimen of one small-bodied member of our genus, H. floresiensis (LB1).
(I'm not sure what "trending towards the primitive condition" means, so I'll ignore that).
The Nature paper by Rex Dalton (Bones, Islands and Videotape) discusses a few of the technical - and rather vicious - criticisms of the Berger paper:
“The more I read their paper, the more I am convinced it is complete nonsense and cannot be accepted as serious science,” says Michael Pietrusewsky
and:
Berger, charges Fitzpatrick, “hasn't made adequate comparisons to other skeletal material from Palau. And I don't think he understands variance in human populations".
That is - those bones aren't small people and this ain't island dwarfing. Dalton suggests that a large part of the problem is how this research is funded by the National Geographic Society. Berger features in a TV show Fossil Hunter, with the slogan “entertainment first, science second". Now, I'm not sure where I stand on the issue of entertainment-based funding and science, and certainly I think Nat.Geo. does some really good work. However, the paper does raise the issue of how science and entertainment tend to get in each other's way:
the Palau story illustrates how science can get caught up in the entertainment process. Like many palaeoanthropologists, Berger has long worked with film crews to document discoveries. But sometimes the demands to catch a significant finding on tape can clash with the slow, rigorous nature of the scientific process. The question anthropologists are asking now is: did entertainment needs in Palau overwhelm the evidence from field research
The new issue of Unscientific American
..has a shock exposé about the truth behind the grand canyon ("it was formed in a couple of days after Noah's Flood says random wild guess by Bible scholar with no knowledge of geography"), and an exclusive interview with creationist (and jailed fraudster*) Kent Hovind.
Ok. Maybe not - it's my favorite entry by el Gran Poco in this week's Photoshop Phriday ("Reverse Magazines") by the goons at Something Awful (nsfw!).
(* I know - I'm repeating myself)
Boskops – a figment of anthropologists’ imaginations
No doubt you've all seen some of the hype surrounding the new book, Big Brain: The Origins and Future of Human Intelligence by Gary Lynch and Richard Granger. The book argues that a long-extinct hominin species, the "Boskops", were much smarter then we are:
Our big brains, our language ability, and our intelligence make us uniquely human. But barely 10,000 years ago--a mere blip in evolutionary time--human-like creatures called "Boskops" flourished in South Africa. They possessed extraordinary features: forebrains roughly 50% larger than ours, and estimated IQs to match--far surpassing our own. Many of these huge fossil skulls have been discovered over the last century, but most of us have never heard of this scientific marvel.
Prominent neuroscientists Gary Lynch and Richard Granger compare the contents of the Boskop brain and our own brains today, and arrive at startling conclusions about our intelligence and creativity. Connecting cutting-edge theories of genetics, evolution, language, memory, learning, and intelligence, Lynch and Granger show the implications of large brains on a broad array of fields, from the current state of the art in Alzheimer's and other brain disorders, to new advances in brain-based robots that see and converse with us, and the means by which neural prosthetics-- replacement parts for the brain--are being designed and tested. The authors demystify the complexities of our brains in this fascinating and accessible book, and give us tantalizing insights into our humanity--its past, and its future.
It seems to be getting glowing reviews all over the place - Cognitive Neuroscientist Michael Gazzaniga says it's "like mixing gas with fire. In this book there are big, explosive ideas by two ingenious brain scientists". William Calvin reviews it in New Scientist ("I've been waiting for someone to write this book for years"). Discover Magazine tells us that the Boskops probably had "an internal mental life literally beyond anything we can imagine".
....and unsurprisingly it's all crap. John Hawks discusses the anthropological evidence for these Boskops and, well, it ain't that good:
This category became untenable as further information about the archaeology of South Africa came to light. Ronald Singer (1958) reviewed the "Boskop race" evidence as it existed by the 1950's. He concluded that there was no reason to maintain that any "big-headed, small-faced group" had existed in prehistory, separate from the current biological variability of "Bushman, Hottentot and Negro." But that view is unsupportable -- in fact, what happened is that a small set of large crania were taken from a much larger sample of varied crania, and given the name, "Boskopoid." This selection was initially done almost without any regard for archaeological or cultural associations -- any old, large skull was a "Boskop". Later, when a more systematic inventory of archaeological associations was entered into evidence, it became clear that the "Boskop race" was entirely a figment of anthropologists' imaginations.