Anthropology
laelaps | March 24, 2008The origin of bipedalism, one of the classic traits popularly cited to separate humans from other primates, has long been a controversial area of research. A number of hypotheses have been floated over the years, but now that more fossil material from the time around the chimpanzee/human split has been uncovered researchers have been able to get a better idea of just how old bipedalism is. In a new paper published in Science, Brian Richmond and William Jungers suggest that the remains of the 6 million year old Orrorin tugenensis provide the earliest known postcranial evidence of hominin…
edyong | March 19, 2008Two weeks ago, I wrote about a Science paper which looked at the effects of punishment in different societies across the world. Through a series of fascinating psychological experiments, the paper showed that the ability to punish freeloaders stabilises cooperative behaviour, bringing out the selfless side in people by making things more difficult for cheaters. The paper also showed that 'antisocial punishment', where the punished seek revenge on the punishers, derails the high levels of cooperation that other fairer forms of punishment help to entrench.
Now a new study published in that…
laelaps | March 18, 2008Last year, in a paper published in the journal Current Biology, Jill Pruetz and Paco Bertolani reported on their observation of ten different chimpanzees thrusting wooden "spears" into holes in trees 22 times over the course of more than a year, presumably to stun bush babies that sleep in the hollows during the day. The report has been somewhat controversial, especially since chimpanzees often shove sticks and twigs into holes, but the observations are receiving some new attention in a National Geographic article about the Fongoli population in Senegal.
Before considering what the Current…
laelaps | March 12, 2008A few weeks ago I picked up a slew of old anthropology books, many of which were at least minimally concerned with figuring out what makes our species human (or what defines "Man," to put things in their historical context). Bipedalism, making tools, and language were the classic examples of features that separate us from the "beasts,"* but prior to any of these books Charles Darwin noticed that it would be practically impossible to point to any one point in our evolutionary history and claim that specific point as the time that our ancestors became human. Even in a time when transitional…
laelaps | March 10, 2008This weekend I had a chance to get through a few shorter anthropology books that I purchased a few weeks ago, including Our Face From Fish to Man, The Leopard's Spots, and Adventures With the Missing Link. The last book, by Raymond Dart, is part autobiography and part popular science book, and the reaction of the public to his famous "Taung child" described within is quite interesting. Some hailed the discovery, others criticized or marginalized it, but for a time it entered the public consciousness as a representation of something ugly and brutish, yet inextricably connected to ourselves.…
gregladen | March 9, 2008It almost seems like there are two separate research project under way regarding the evolutionary history of Homo sapiens. One focuses on recent humans, tends to use DNA as a major source of information, and from this base projects back into the past. This approach tends to confirm the idea that humans share an African origin with a subsequent spread from Africa, with various degrees of complexity in that series of historical events. The other focuses on early human remains, sometimes including remains that would be placed by some in a separate species or sub species. This sort of…
laelaps | March 8, 2008SmilodonIt's been two weeks since the last Boneyard weathered out of the blogosphere. Here's a look at what present excavations have revealed over the past two weeks;
Carnivorous mammals have evolved saber-teeth many times in the past, but just how they used their teeth to kill prey has been more difficult to ascertain. Nimravid presents a short review of how creatures so equipped may have caught and killed their prey.
Paleontology isn't only focused on nightmarish creatures that ripped other extinct animals to shreds; the Ethical Palaeontologist reports on an amazing fossil of a Triassic-…
laelaps | March 6, 2008Today I had the pleasure of giving an interview to a local NPR radio station about the infamous Hesperopithecus, and I'll provide you all with a link as soon as the feature is up. I was a little bit nervous, but I think I did alright.
[As an aside, if things have been a little light on here lately it's because this past week has been, in no uncertain terms, hellish. Between midterms, being sick, writing a few pages of my book every night, and still fighting the university to let me major in evolutionary anthropology, I've been feeling a little drained. Spring break is coming up soon, though,…
edyong | March 6, 2008
Humans have an extraordinary capacity for selflessness. We often help complete strangers who are unrelated to us, who we may never meet again and who are unlikely to be able to return the favour. More and more, we are being asked to behave in selfless ways to further the common good, not least in the race to tackle climate change.
Given these challenges, it's more important than ever to understand the roots of cooperative behaviour. From an evolutionary point of view, it can be a bit puzzling because any utopic society finds itself vulnerable to slackers, who can prosper at the expense of…
gregladen | March 6, 2008There is a fairly new paper in PLoS on the colonization of the New World. It is the latest in a series of attempts to synthesize biogeography, climate change related paleoenvironmental reconstruction, genetics, and archaeology.
The authors draw these conclusions:
These results support a model for the peopling of the New World in which Amerind ancestors diverged from the Asian gene pool prior to 40,000 years ago and experienced a gradual population expansion as they moved into Beringia. After a long period of little change in population size in greater Beringia, Amerinds rapidly expanded into…
laelaps | March 6, 2008
There's a new paper out in the Proceedings of the Royal Society B about the ever-controversial Homo floresiensis, the authors of the paper arguing that the fossils representing this new species are actually "myxoedematous endemic cretins," of the species Homo sapiens. The condition the authors propose is expressed by the Flores hominid is generally caused by a lack of iodine in the diet, such a deficiency causing the thyroid gland to produce improper amounts of hormones associated with bone growth and brain size, resulting in mentally-impaired individuals of small stature. So far the paper…
gregladen | March 6, 2008There is a new paper out suggesting that the Flores hominids, known as Hobbits, were "human endemic cretins."
From the abstract of this paper:
... We hypothesize that these individuals are myxoedematous endemic (ME) cretins, part of an inland population of (mostly unaffected) Homo sapiens. ME cretins are born without a functioning thyroid; their congenital hypothyroidism leads to severe dwarfism and reduced brain size, but less severe mental retardation and motor disability than neurological endemic cretins. We show that the fossils display many signs of congenital hypothyroidism, including…
gregladen | February 28, 2008This is a photograph of wild western lowland gorillas copulating in, sort of, the missionary position. This shot was taken in the Nouabale-Ndoki National Park in the Republic of Congo.
The female gorilla in the photograph, nicknamed "Leah" by researchers, has twice made history. In 2005 Breuer and others observed her using tools--another never-before-seen behavior for her kind in the wild. Leah tested the depth of a pool of water with a stick before wading into it in Mbeli Bai, where researchers have been monitoring the gorilla population since 1995.
"Understanding the behavior of our…
gregladen | February 28, 2008A DNA phylogeny based on over 200 species of lemurs and related species is now available.
Lemurs are part of the large group known as the strepsirrhine primates (yes, three r's...)From the abstract of this paper, coming out in March in Genome Research:
... strepsirrhine primates are of great interest ... due to their phylogenetic placement as the sister lineage to all other primates. Previous attempts to resolve the phylogeny of lemurs employed limited mitochondrial or small nuclear data sets, with many relationships poorly supported or entirely unresolved. We used genomic resources to…
laelaps | February 21, 2008Nebraska Man as restored in the Illustrated London News.As I made my way around the lab table during my last human osteology practical, examining the yellowed and cracked teeth in the hopes that I'd be able to tell an upper molar from a lower one, I came across a particularly strange tooth. I had been told by the professor that 3rd molars ("wisdom teeth") can be strange and don't always conform to the rules that makes identifying other molars comparatively easy, but this specimen was simply bizarre. The arrangement of cusps and folds on the crown of the tooth didn't correspond to any of the…
gregladen | February 19, 2008
Fallback foods are the foods that an organism eats when it can't find the good stuff. It has been suggested that adaptive changes in fallback food strategies can leave a more distinct mark on the morphology of an organism, including in the fossil record, than changes in preferred food strategies. This assertion is based on work done by the Grants and others with Galapagos Island finches, by Richard Wrangham and me with hominids, and by Betsy Burr and me with rodents.
The reason for this is simple. There is a rough correspondence between how much energy one can obtain from a food type and…
gregladen | February 19, 2008Comparing living chimpanzees to living humans, in reference to the species that gave rise to these two closely related species, is one way to frame questions about the evolution of each species.
Generally, it is useful to address evolutionary questions by comparing two living species with the reconstructed "last common ancestor" (LCA) of those species. All of the similarities and differences between the LCA and the living form, in each lineage, represent evolutionary "stories" (that could even be worked out as hypotheses). Similarities indicate important, long-maintained adaptations, and…
gregladen | February 17, 2008We are only a tiny ways through the voyage. Need to hurry up! So, let's skip ahead a bit and hit the Gauchos.
Well, you don't really want to hit at Gaucho ... they hit back rather hard....
The Gauchos are the cowboys of the so-called Southern Cone and Pampas. The Gauchos are a Latin American version the horse mounted pastoralists that emerge wherever four things are found together: Grasslands, horses, people and cattle. Like all horse-mounted pastoralists, they have been known to have certain cultural tendencies or traits. These include being incredibly good horse riders. It includes…
neurophilosophy | February 13, 2008The 3-minute film clip below is definitely not for the squeamish. It comes from a documentary called A Hole in the Head, made in 1998, and shows a Kisi medicine man performing the "operation of the skulls".
gregladen | February 13, 2008Bats; Signaling in the Rain Forest; Sumatran Tiger Body Parts; Humans in the New World 20,000 years ago.
Bats are funny. Funny strange, not funny ha ha. There are two kinds of bats, microchiroptera and megachiroptera. The micros are smaller, the megas larger, by and large. and the micros have bat-sonar, while the mega's don't The micros tend to eat insects, the megas tend to eat fruit. Micros are more global in their dsitribution, mega's are more tropical.
It is not the case that all of the evidence regarding bat evolution clearly indicates that the common ancestor of both kinds of…