Casting

Virtual paleontology activity

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Last week Nazarbayev University hosted an Instructional Technology Showcase, in which professors demonstrated some of the ways we use technology in the classroom. This was the perfect venue to show off the sweet skeletal stuff we study in Biological Anthropology, through the use of pretty “virtual” fossils. In the past year I’ve started using CT and laser scans of skeletal remains to make lab activities in a few classes (I’ve posted two here and here). Such virtual specimens are especially useful since it is hard to get skeletal materials and casts of fossils here in the middle of the Steppe. These scans are pretty accurate, and what’s more, 3D printing technology has advanced such that physical copies of surface scans can be created from these virtual models. So for the Showcase, I had a table where passersby could try their hand at measuring fossils both in hand and in silico.

Lower jaw of an infant Australopithecus boisei (KNM ER 1477). Left is the plastic cast printed from the laser scan on the right.

Lower jaw of an infant Australopithecus boisei (KNM ER 1477). Left is the plastic cast printed from the laser scan on the right.

The Robotics Department over in the School of Science and Technology was kind enough to print out two fossils: KNM ER 1477, an infant Australopithecus boisei mandible, and KNM KP 271 a distal humerus of Australopithecus anamensis. They used a UP Plus 2 printer, a small desktop printer that basically stacks layers of melted plastic to create 3D models; they said it took about 9 hours to print the pair. Before the Showcase, I measured the computer and printed models on my own for comparison with published measurements taken on the original fossils (KP 271 from Patterson and Howells, 1967; ER 1477 from Wood, 1991). The virtual fossils were measured using the free program Meshlab, while basic sliding calipers were used to measure the printed casts.

I was pleasantly surprised at how similar my measurements were to the published values (usually within 0.1 mm), since it means that the free fossil scans provided by the National Museums of Kenya are useful not only for teaching, but potentially also for research.

The Virtual Paleontology Lab

The Virtual Paleontology Lab. The Kanapoi distal humerus is held in the foreground while the A. bosei jaw rests on the table. Yes, those are real palm trees.

Knowing that these models are pretty true to life (well, true to death, since they’re fossils), I was curious how students, faculty and staff would do. I picked two fairly simple measurements for each fossil. None of the people that came by to participate had any experience with bones or fossils, or measuring these in person or on a computer. Here are their results:

Boxplots showing participants' data, for two measurements on each of the fossils. The blue stars mark the published values. The red rugs on either side indicate measurements taken on the scans (left side) or printed casts (right).

Boxplots showing participants’ data, for two measurements on each of the fossils. The blue stars mark the published values. The red rugs on either side indicate measurements taken on the scans (left side) or printed casts (right).

For the most part, the inexperienced participants’ measurements are not too far off from the published values. There’s not really an apparent tendency for either cast or computer measurements to be more accurate, although measurements of the Kanapoi humerus are closer than the computer measurements (third and fourth boxes above). In my personal opinion, nothing beats handling fossils (or casts of them) directly, but this little activity suggests students can still make reliable observations using 3D scans on a computer.

Sweet free stuff:
Meshlab software
3D scans of fossils from the National Museums of Kenya

I, or someone, have drawn a brown, orange, and blue Gwenhidwy

/ zcofran / 2 Comments

You’re probably thinking, “I thought zacharoo was dead,” because I’ve been completely MIA for the past few weeks. My apologies, but I was trying to wrap up this past semester, the terminus of my first year in grad school. And I must say I think I did a pretty good job, not to toot my own horn. This is as good a time as any to ask, “What the eff have I learned this year?”

1. Milford is awesome. Probably the past few decades have shown this, but I’ve only known the guy for less than a year. Given my more ‘arts’ educational background, Milford (and the Big Chief and the rest of the bios) have taught me how to do ‘science,’ formulating and testing a hypothesis. Though I’m certainly no Chung-I Wu, my mentors and colleagues have certainly gotten me started. Also, I was a bit unhappy with Milford last semester for pushing me and my peers to take a heavy course load. But I must say it was worth it, I’ve learned a lot this past year, and if I’d taken another (i.e. the non-bio) way I would not have learned nearly as much. He can also improvise a wicked country-twangy song (“I wish I grew up on a pig farm”). Great advisor, great man.

2. Steer clear of the hobbit. That situation is messier than the van-ride back from DC. I talked about LB 1 (the hobbit skull) in a few posts earlier this year. It’s clearly not a cretin, and at the AAPA meetings in Columbus a few weeks ago, Dean Falk defensively countered the Laron Syndrome hypothesis. Bill Jungers reported at the meetings that the foot of LB 1 was not that of a runner (I forget the specifics, but it was missing one or both of the plantar arches). It’s overall cranial shape based on various measurements show it has striking affinity with Homo habilis (in a broad sense) <!–[if supportFields]> ADDIN EN.CITE Gordon200810310317Gordon, Adam D.Nevell, LisaWood, BernardThe Homo floresiensis cranium (LB1): Size, scaling, and early Homo affinitiesProceedings of the National Academy of SciencesProc Nat Acad SciProc Nat Acad Sci07100411052008March 20, 2008http://www.pnas.org/cgi/content/abstract/0710041105v1 10.1073/pnas.0710041105<![endif]–>(Gordon et al. 2008)<!–[if supportFields]><![endif]–>. Chief, her husband Adam, Pappano, and I looked at UM’s collection of modern human ‘microcephalics’ (there are myriad ways to be microcephalic), and found that LB 1 is still more similar to the habilines (cf. Gordon et al 2008). This really suggests to me that maybe some early Homo or Australopithecus species made it out of Africa to Flores early in human prehistory; however, I don’t think we can say yet whether it’s a real case of insular dwarfing in a hominin or pathology or what. Still very messy.

3. Molding and casting is neat but difficult. One of the projects Milford got me started on a cranial reconstruction. Sounded simple enough at first, but it has required me to make molds and casts of the individual cranial bones: the two temporals, occipital and the paired parietals were not too difficult, but the face is really giving me grief. It was also difficult fitting my busy schedule to Bill Sanders’s lab schedule. So, long story short, I didn’t finish the project (should be done before June . . .), but Bill has taught me a ton about molding and casting, as well as proffered his wisdom. It has also reinforced my desire to be a paleontologist. Cool beans.

4. Genetics sucks. For decades now, paleoanthropology has come to be not just about fossils, but also about molecules. Today, genetic studies are incredibly influential in studies of human evolution, i.e. supporting models of migration and introgression. But I took a course this past semester in the department of Ecology and Evolutionary Biology, and it seems to me that molecules are not really any less unequivocal than fossils. Really genetics is all comparing predictions of models with various parameters (i.e. effective population size, population expansion, etc.) with actual empirical data, and it’s all about probability. So you can say something like, “There is a high probability of seeing this type of data given that type of hypothesis/model.” But different sometimes data have the same probability given different parameters. So genetics can tell a lot, but you have to take what they say with a gram of coke, I mean granary of salt. And all the nucleotides in the world probably won’t help resolve robust australopithecine phylogeny.

Now I’m tired, so I’ll stop there for now. I’ll post more pearls (of wisdom) I learned this semester as I recall them. So that’s where I’ve been o’er the past few somethings. Weeks. Oh, and I just received a possible job offer working with crash-test dummies (or something, I’m not exactly sure) with the UM Transportation Research Institute, hopefully that works out.

Reference

<!–[if supportFields]> ADDIN EN.REFLIST <![endif]–>Gordon AD, Nevell L, and Wood B. 2008. The Homo floresiensis cranium (LB1): Size, scaling, and early Homo affinities. Proceedings of the National Academy of Sciences:0710041105.