Archive for February, 2009
Unsurprisingly, the original version of this post has been getting some traffic lately. I was going to revamp it and repost, but
On February 12th, 1809, two visionaries emerged on opposite sides of the Atlantic. Both were cautious, erudite, soft-spoken men who were destined to transform the world in their own way.
In a letter to Asa Gray Darwin, a self-proclaimed supporter of the Union endorsed Lincoln’s Emancipation Proclamation:
Well, your President has issued his fiat against Slavery—God grant it may have some effect.
I don’t know if Lincoln ever picked up the Origin.
I suppose he was rather busy in the sixties. He is reported to have read (and enjoyed) Robert Chambers’ Vestiges. While this proto-evolutionary text was widely derided by the scientific community (including Darwin himself), it did mark a sincere effort to develop a rational history of life that accorded with the fossil record.
Growing up in Kentucky, it’s almost impossible that a young Abe didn’t encounter some of the abundant Paleozoic fossils that litter the state. And, in keeping with my previous rant about our fossilferous infrastructure, the stone which surrounds Lincoln’s tomb is packed with coral and brachiopod fossils.
Perhaps it’s no coincidence that Lincoln’s most famous address, delivered amongst fields tilled with fallen soldiers, begins with a declaration of historical context. History helps us to make sense of chaos and savagery of modern life. This is also where Karl Marx and L. R. Hubbard fit in.
But aside from that, Mrs. Lincoln how was the play?
Here’s the first batch of Darwin day cupcakes we made (well, Jessica did all of the work on these). These are Earl Grey & Murcott Orange cupcakes as seen on Vanilla Garlic. We were fortunate enough to track down Murcott Oranges (a.k.a. honey tangerines) but I would bet that in a pinch any tangor would do, you might even be able to get away with some other mandarin hybrid.
Um, you might have noticed that there are some letters missing…I got hungry. Just kidding I ruined them when I packed them up, chalk it up to “survival of the fittest?
You’ll no doubt recognize the decoration on the lower left, but who can identify the one on the right? It stumped the geology faculty, though granted it’s not a great likeness…
Happy Darwin Day!
“In a word, the form of the tooth entails the form of the condyle; the forms of the shoulder blade and the claws, just like the equation of a curve, entail all their properties. Just as in taking each property seperately as the basis for a particular equation, one would find both the ordinary equation and all the other properties of any kind, so likewise the claw, the shoulder blade, the condyle, the femur, and all the other bones taken seperately, determine the teeth, and each other reciprocally. Beginning with each of them in isolation, he who possesses rationally the laws of organic economy would be able to reconstruct the whole animal.” — Cuvier 1812, trans. Martin Rudwick.
Baron Georges Léopold Chrétien Frédéric Dagobert Cuvier was a man of strong opinion and bold statement. In the most dramatic articulation of his “Principle of the Correlation of Parts” Cuvier argued that anatomy, like God, bows to math. Given a single isolated bone, he claimed, one might be able to infer what the entire animal looked like, at least in principle. In following paragraphs Cuvier hedges his bold assertion just a bit, but this is the idea for which Cuvier is remembered, and misremembered, the most.
Creationsists love to bring this up, “scientists find a few scraps of bone and make up a dinosaur.” Ironically, it was Cuvier’s own vision of “intelligent design” and “irreducible complexity” that informed his view. On the opposite side of the spectrum, Thomas Henry Huxley took Cuvier’s claim to task in his lecture “On Natural History, as Knowledge, Discipline, and Power” (see also Hugh Falconer’s rebuttal). In a later, and tremendously entertaining essay, “On the Method of Zadig” Huxley argues that Cuvier’s principle can be of some use, as long as it is conducted cautiously and in an explicitly evolutionary context.
These days most paleontologists would claim that they aren’t so bold as Cuvier, and that they wouldn’t seriously attempt to reconstruct an animal based upon a single bone (though they certainly might do so for a laugh). I would argue, however, that we’ve actually gone far beyond Cuvier’s wildest dreams. Correlation and exrapolation are largely the name of the game. This is how we sex the brooding theropod, draw out the fetal leviathan, and diagnose the dueling dinosaur.
The much publicized recent discovery of Titanoboa is significant not only because it’s a freaking huge-ass snake, though admittedly it is one ginormous, redonkulus, totally protarded animal. Even more amazing than the snake is what Jason Head and coauthors* do with the fossils. Given a handful of vertebrae from several individuals, they first extrapolate the body size of the animal based on the anatomical proportions found in the largest living snakes, python and anaconda. Then, and this is the really amazing part, they use the size of the snake to calculate paleo temperature based on the relationship between geographic distribution, temperature and body size among living reptiles. In fact, the authors even propose a pole to equator temperature gradient–based on the size and shape of the backbone of an extinct snake!!
If the scientists were simply saying “big snake = tropical weather,” as most news outlets are basically reporting it, that wouldn’t be very noteworthy. But this may be the first time that a fossil vertebrate has been used to calculate a numerical paleotemperature estimate. At last year’s Society of Vertebrate Paleontology Conference I saw one of the authors, David Polly, give a pretty amazing lecture using ankle bone shape to estimate paleoenvironment and paleoclimate.
Taking the temperature of the tropics with a snake – Head et al. 2009
This kind of claim is certain to draw criticism and skepticism within the paleontological community and, probably especially, from neontologists and paleoclimatologists. That’s not neccesarily a bad thing, radical new ideas in science need to be tested. I’m certainly not totally convinced. Still, for a science as old and dusty as comparative anatomy, it’s pretty exciting to see this kind of novel and creative work. It gives me hope that there are plenty of new surprises out there still waiting to be discovered. Cuvier would be proud I think.
For more huge-ass snakes see: Snake Handlin’
* – full disclosure, I’m friends with one of the authors and have worked with him in the field.
“Um…what are you working on?” my lab mate asked. A few hours earlier she had shown me a truly rank skull that she had just dissected from a frozen chimaerid.
“Oh..um…well…” I paused to consider my explanation. “There’s a new paper out in PNAS about the discovery of thousand-year-old chocolate at Chaco Canyon in New Mexico. So, um I decided to design a cereal box based on that concept…”
“Oh, okay. I’ll let you get back to that…”
For the record, the cereal’s mascot is named “Cocoapelli.” Hat-tip to Will Baird for the name “Choco Canyon.”
about marmots (woodchucks &c.):
- marmots are basically squirrels with a weight problem
- “wuchak” is a Cree word whose corruption is supposed to have given rise to the English “woodchuck.” However, “wuchak” apparently means “fisherman” in Cree and the name originally applied to the fisher (“Martes” pennamti), a large weasel that bears almost no resemblance whatsoever to a woodchuck/groundhog/marmot aside from being furry and brown. Except, hold on a minute, the name “fisher” has nothing to do with “fishermen” in the first place, it’s supposedly a corruption of the French word for a polecat pelt “Fichet.” So it’s not entirely clear why the Cree word for “fisherman” should be used for either animal. So, WTF? “Wuchak”?
- Marmota monax is more closely related to Eurasian marmots than the mountain marmots of the American west, suggesting that a band of intrepid groundhogs once (or perhaps more than once) crossed Beringia and invaded Eurasia, although some other scenarios are possible.
- awesomely, wikipedia has six suggested responses to the old “how much wood…” tongue-twister, three of which are properly referenced with footnotes. Astonishingly, the response I learned as a child “A woodchuck would chuck lots of wood if a woodchuck could chuck wood” is absent although, admittedly, it’s not very imaginative compared to, say “42 pounds.” Still, any wikipedia editors out there, feel free to cite microecos on that one.
- here is a recipe for fried woodchuck, from this very useful site. I would bet this recipe could be adapted for any medium – large rodent, you might want to adjust the cooking time:
1 tbsp salt
1 cup flour
2 tbsp fat
Clean woodchuck; remove glands; cut into 6 or 7 pieces. Parboil in salted water for 1 hour. Remove from broth; roll in flour and fry in hot fat (deep fat may be used) until brown. Serves 6.
- More over at Oryctology.