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Thursday, May 22, 2008

May-stuffs

Some fun new things in anthropology of late. For starters, friend and colleague Adam Van Arsdale co-authored a paper recently released in Journal of Human Evolution about variation in the Dmanisi mandibles (Rightmire et al.). Dmanisi, in the Republic of Georgia and dating to about 1.77 mya, is interesting because the human fossils (Homo erectus) there represent the earliest definite excursions of hominins outside of Africa. Also interesting is the fact that the assemblage very likely represents a “paleodeme,” i.e. an actual living population. It was recently reported (de Lumley et al. 2008) that the Dmanisi hominins were probably a single group that was trapped quickly in a volcanic catastrophe—bad for them, good for paleontologists. So, Philip Rightmire, our friend Adam and David Lordkipandize have written a paper in response to an earlier paper suggesting that the size variation in the Dmanisi mandibles was so great that it represents more than one taxon. Rightmire and colleagues demonstrated, I think convincingly, that much of this ‘dimorphism’ is likely the result of taphonomic (the D2100 mandible is broken inferiorly), pathological and ontogenetic factors (the D2600 mandible is huge, possibly due to its advanced age and “pathology associated with dental wear”). So Dmanisi is pretty sweet: very early Homo all the way out in Georgia at least 1.7 mya, and we have a good collection of what probably represents not just a single, dimorphic species, but an actual (sub)population. Kudos, Adam!

What else…Oh yes! Another recent study suggests that vertical climbing costs the same energy per unit of body-weight in primates (Hanna et al. 2008). Jandy Hanna (no—apparently it’s not a pseudonym) and team MacGyvered a vertical climbing treadmill that also recorded energy expenditure (they had more than just a coat hanger, hock of Silly Putty and a tube sock), and subjected some small-bodied primates to some bouts of vertical climbing (man, anthropology can be sweet). They somehow also included humans in this study, but I’m not exactly clear on how yet, maybe I’ll consult their Supporting Material and get back to you on that. Anyway, they found that across the body sizes (from .17 kg to 1.4 kg) vertical climbing efficiency is more or less equal; humans fall within the confidence limits. Which is cool because as primates increase in body size they become more efficient at walking. This is because increased body size is associated with longer legs, requiring less muscle activity to keep moving. What does this mean? This suggests to the authors that the very earliest primates (Back to the Eocene) were probably very, very small-bodied, and this small size allowed them to move into a vertical-climbing niche with little to no energetic cost. It would be really interesting to see this study performed on more primate taxa, especially larger body sizes, maybe comparing monkeys to apes.

Finally, apparently the verdict is in: “Great Apes prefer cooked food” (Wobber et al.). I could have told you that, I mean think: a delicious medium steak vs. crappy, uncooked, parasite-teeming jungle fruit? The point was to test the hypothesis that food preparation in the form of cooking probably occurred and was widely accepted quickly after hominins garnered control of fire. Richard Wrangham (3rd author on the paper) has been into the idea that cooked food was superlatively important in the course of human evolution (see “Out of the Pan and into the fire” in Tree of Origin, edited by Franz de Waal (2001)), and I suppose here he set out to examine the issue scientifically. I’m not terribly informed about or interested in this issue, though it is a bit neat. Basically they went to the Yerkes primate research facility in Hottlanta and the Leipzig Zoo and gave chimps, bonobos, gorillas, and orangutans free-will choices between raw and cooked tubers processed various ways. Most of the time the cooked tuber (or apples or beef, in some cases) was selected, and eureka there’s proof that early hominins had this inherent preference for something about cooked food, appeasing the Chef Boyardee inside them. They end with, “Overall, our findings conform to evidence that wild chimpanzees choose seeds that have been heated by wild fires (Brewer, 1978), demonstrating that great apes possess a preference for cooked items” (Wobber et al., in press). Well, maybe. I think cooked seeds are a bit different from cooked tubers and meat. Plus, these tests were all conducted on captive apes, many of whom had eaten cooked food before, sometimes regularly. I know it’s less feasible, but it would be more convincing if somehow wild apes could have been tested with foods they’d be most likely to encounter in the wild.

What the paper didn’t address, and which I think is much more interesting, is how (and when) exactly these early hominins would have cooked food. Bear with me. So you’re a hominin with fire—did you make it or did you find it naturally somehow?—and you know that it’s super effing hot, it can harden sticks, it scares away some predators, and that generally when things go into it they don’t come out of it. Why the hell would you throw your hard-earned food into it? Perhaps the earliest chefs noticed that wild-fire heated foods (cf. the chimps, above) were preferable to raw ones, for whatever reason, and maybe they started trying it with multiple foods. Ok, but how did they cook? In Wobber et al.’s experiment the tubers were oven-baked, but I don’t think they had Kenmore ovens in the Pleistocene. I don’t know, maybe I’m over-thinking this (I usually do), but I think what’s much more interesting, and admittedly more difficult to find out and test, is how the earliest cooking would have been done. Honestly I thought this paper was a bit silly. I mean if you want to go to the zoo, you don’t have to come up with an experiment. The Lincoln Park Zoo in Chicago is free—and they have a one-armed gibbon that is super sweet.

Anyway, that’s the news hereabouts. Oh, Jerry De Silva just successfully defended his PhD dissertation, and his talk was really cool and informative (it was about climbing and feet, and you know how I love climbing). This Wednesday Robin Nelson will be defending her dissertation, and although I’m no psychic, no Johnny Carson, I’m pretty confident that her talk will be interesting and that she will defend successfully. So congratulations to Jerry and (prematurely) to Robin! Oh, and Kristen got a job and her research grant, so Kudos to her, too. And I’m gonna run my first half-marathon in a week and a half. Sweet.

References

de Lumley M-A, Bardintzeff J-M, Bienvenu P, Bilcot J-B, Flamenbaum G, Guy C, Jullien M, de Lumley H, Nabot J-P, Perrenoud C, Provitina O, Tourasse M (2008) Impact probable du volcanisme sur le décès des Hominidés de Dmanissi. Comptes Rendus Palevol 7(1):61-79

Hanna JB, Schmitt D, Griffin TM (2008) The Energetic Cost of Climbing in Primates. Science 320(5878):898-

Rightmire GP, Van Arsdale AP, Lordkipanidze D Variation in the mandibles from Dmanisi, Georgia. Journal of Human Evolution In Press, Corrected Proof

Wobber V, Hare B, Wrangham R Great apes prefer cooked food. Journal of Human Evolution In Press, Corrected Proof

Wednesday, May 14, 2008

summerployment

the summer job search. it's one of those painful, inevitable parts of life that lies somewhere between the inebriation following finals and the packing/moving of your crap preceding the fall semester. if you're responsible and on top of things, you start in advance. for once in my life, i DID start very, very far in advance (almost immediately after arriving in ann arbor) - what to do this summer? i had some ideas, which fell apart, until my advisor and i finally worked out a somewhat do-able project for summer. but then there was that pesky question of "funding," required for, you know, such pursuits as "paying rent," and "not starving." so we applied for a grant. oh, the grant application. what a stupid exercise in frivolous question answering and detail-providing. i know, i know. i'm a grad student. i'm going to write like, a million billion (trillion?) of these applications, and so on. however, the experience i have had in waiting for the holy grail of graduate life - a GRANT - has been frustrating, annoying, and downright irritating (i think those are all synonyms. i dont care. moving on...).

so what did i do? i started to look for a "real" job. not a real real job - like being an investment banker, a teacher, or a tortured muscian - but a job to pay my rent. here is just a SAMPLE of some of the positions for which i have applied, for purely entertainment value:

- Banana Republic: which actually HIRED me and seemed to have FIRED me before i even attended job training. they didn't even wait to find out i'm a terrible employee before not returning my calls. awesome.

- Radiology lab technician: hey, under job requirements it said "willing to learn." there was nothing mentioned of "expertise" or "previous experience."

- Helping with an elementary school summer program: i love love children, but dealing with snot and knee scrapes every day for 16 weeks might have made me hate hate them.

- Research assistant: okay, i've applied to like 50 of these positions. i went to one interview where i found out i had to know alot about "databases." they asked me, "what types of online databases do you use in your work?" to which i replied "Google Scholar."
--in another interview for a research position, i realized i had no experience with any statistics programs, even though in the job description one of the requirements was "advanced knowledge of SAS." oops.

- Receptionist at a hair salon: hey i actually wanted this job. free haircuts? are you kidding? awesome. but they never called me back.

- Caterer: i have never worked in a restaurant or catering in my entire life. i can barely make a sandwich, okay...

- American Apparel: i don't think this store will hire me, because i don't know if i'd be allowed to wear things with prints. and i certainly would not be allowed to eat. i tried on some clothes in there once, i don't know if they make my size. size not zero?

- Urban Outfitters: they have sections on their application for "the last 3 CDs you bought" and "the last magazine you read." in addition to experience and skills requirements, this place also has a "cool" requirement. don't get me wrong, i love this store. but seriously...i am definitely not cool enough to work there.

this is just a small number of the jobs i have applied for, because they are more entertaining than the rest. i have a job interview tomorrow and one on friday (at J. Crew, which when they called me - i won't lie, i almost passed out). let's just hope these go better than my previous 10 or so flubs. or i might be living on the street in a month.

Language Time!

Foreign language requirement time, that is. Guten Tag, meine Damen und Herren. Three (drei) days into my German 101 class and so far so good (gut).

I know we all have this requirement to fill, and that Milford the Great only requires us to be able to read articles in a foreign language (French, German, Italian...). As such, I thought you might be interested in this site. It works like this: copy your foreign language text that you're trying to read and paste it onto the site. The site then hyperlinks all of the words so that when you click on them, the dictionary translation pops up in a new window. The usefulness of this is that it allows you to read a block of text to the best of your ability, quickly looking up the (hopefully few) vocab terms that stump you. It also keeps track of the words you click on and gives you a vocab list of terms to study once you're done, so that the next time you come across them maybe they won't look so foreign. Since the typical intro language book doesn't cover terms like "paleoanthropology, anterior superior iliac spine, hominid origins, etc." I thought this might be a useful way to learn them in context based on the articles you need to be able to read.

Tschuess!

Friday, May 9, 2008

New twist from teeth

Peter Ungar, Fred Grine and Mark Teaford recently reported in PLoS ONE on their results of studying the microwear on Australopithecus boisei molars. Their study showed that the microwear differs from that of A. robustus, arguably boisei's South African counterpart, and from A. africanus. Here's the abstract:
The Plio-Pleistocene hominin Paranthropus boisei had enormous, flat, thickly enameled cheek teeth, a robust cranium and mandible, and inferred massive, powerful chewing muscles. This specialized morphology, which earned P. boisei the nickname “Nutcracker Man”, suggests that this hominin could have consumed very mechanically challenging foods. It has been recently argued, however, that specialized hominin morphology may indicate adaptations for the consumption of occasional fallback foods rather than preferred resources. Dental microwear offers a potential means by which to test this hypothesis in that it reflects actual use rather than genetic adaptation. High microwear surface texture complexity and anisotropy in extant primates can be associated with the consumption of exceptionally hard and tough foods respectively. Here we present the first quantitative analysis of dental microwear for P. boisei. Seven specimens examined preserved unobscured antemortem molar microwear. These all show relatively low complexity and anisotropy values. This suggests that none of the individuals consumed especially hard or tough foods in the days before they died. The apparent discrepancy between microwear and functional anatomy is consistent with the idea that P. boisei presents a hominin example of Liem's Paradox, wherein a highly derived morphology need not reflect a specialized diet.

Note that they refer to boisei and robustus as "Paranthropus," whereas I (and others) refer to them as Australopithecus. A. boisei and robustus are two "robust" australopithecines, described as such because their skulls and teeth suggest these guys were adapted for prolonged, powerful bouts of mastication (it means chewing, get your mind out of the gutter). Some people argue that these two taxa form a monophyletic group; that is, they share a last common ancestor that is not shared by any other taxon. If this is the case, the generic distinction (Paranthropus) can be made, separating them from the other australopithecines. Though I tend to lump groups, I really think that these taxa do not form a monophyletic group, that they have different ancestors (that their superficially similar masticatory apparati were independently evolved), and that they should stay in the genus Australopithecus. Right now, this issue (wherein I am very interested) has yet to be resolved.

Anywho, what's important here is that the two robust austrlopithecines differ in their microwear patterns, which suggests that the two subsisted on different diets. Similarly, Wood and Constantino (2007) report that the stable carbon isotope signal from boisei (yet unpublished, but communicated to them personally by Matt Sponheimer) is different from the A. robustus and africanus. Together, these two data indicate that the robust australopitheciens (not to speak about A. aethiopicus...) were quite different in their diets (and possibly lifestyles?). Interestingly, A. robustus's molar microwear and stable isotope signals are very similar to that of A. africanus, who was present in the same regions as robustus but a bit earlier in time. This bolsters the scenario in which A. robustus is evolved from A. africanus, or something like it. Could this suggest also that A. boisei is not descendant from A. africanus? Or, is it simply that there were different foods available in the Plio-Pleistocene of South and East Africa?

Another important note that the authors bring up is the fact that of the seven specimens examined, none appeared to have eaten tough or hard foods that might necessitate the use of their (we assume) powerful masticatory muscles. Now why the hell would they have such a derived face, jaws and teeth if they were not eating things that would have required such an apparatus? One proposed scenario about the "hyper-robust" masticatory apparatus of A. boisei is that it is an adaptation for only the toughest of times, when survival might have hinged upon the ability to process and ingest the lowest quality (and hardest to eat) foods. Ungar et al.'s data suggest that this may well be the case, that the powerful masticatory apparatus came in handy only very rarely, and so the dietary signal from microwear reflects what these critters usually ate (and preferred to eat).

If this is really the case, then it might suggest that the robust face of boisei was almost completely genetically acquired, that epigenetic factors did not contribute greatly to produce boisei's face. This could be important for teasing out criteria (i.e. skeletal, craniofacial traits) useful in phylogenetic reconstruction. For example, it could be that certain robust features of boisei's face indicate a shared genetic ancestry, whereas those of robustus were more epigenetic in nature, acquired over a lifetime of experiencing high chewing forces. Contrariwise, these traits might be the result of these two taxa's shared ancestry.

Either way, this paper presents interesting new information about the most bizarre hominin evolutionary dead-end, the robust australopithecines.

References

Ungar PS, Grine FE, and Teaford MF. 2008. Dental Microwear and Diet of the Plio-Pleistocene Hominin Paranthropus boisei. PLoS ONE 3(4):e2044.

Wood B, and Constantino P. 2007. Paranthropus boisei: Fifty years of evidence and analysis. American Journal of Physical Anthropology 134(S45):106-132.

Thursday, May 1, 2008

Gwenhidwy Pic


My last post was entitled "I . . . have drawn a brown, orange, and blue Gwenhidwy." So here's the actual picture that I drew, so you guys wouldn't think I'm a liar. Here's the original line, from Gravity's Rainbow:

"Arch, or someone, has drawn a brown, orange, and blue Gwenhidwy carrying a doctor's bag along a flat horizon-line past a green gasworks. The bag's full of gin bottles, Gwenhidwy is smiling, a robin is peeking out from its nest in his beard, and the sky is blue and the sun yellow." If you would like to order prints of this incredible masterpiece, here are prices: 4"x6"- $20.00, 3'x5' - $125.00; and for an exorbitant sum of moneys I will paint this on an entire wall of your house/apt.