Friday, June 18, 2010

Baraminology in Journal of Evolutionary Biology

What do you know? There's a really nifty new paper in Journal of Evolutionary Biology by Phil Senter:
Using creation science to demonstrate evolution: application of a creationist method for visualizing gaps in the fossil record to a phylogenetic study of coelurosaurian dinosaurs

It is important to demonstrate evolutionary principles in such a way that they cannot be countered by creation science. One such way is to use creation science itself to demonstrate evolutionary principles. Some creation scientists use classic multidimensional scaling (CMDS) to quantify and visualize morphological gaps or continuity between taxa, accepting gaps as evidence of independent creation and accepting continuity as evidence of genetic relatedness. Here, I apply CMDS to a phylogenetic analysis of coelurosaurian dinosaurs and show that it reveals morphological continuity between Archaeopteryx, other early birds, and a wide range of nonavian coelurosaurs. Creation scientists who use CMDS must therefore accept that these animals are genetically related. Other uses of CMDS for evolutionary biologists include the identification of taxa with much missing evolutionary history and the tracing of the progressive filling of morphological gaps in the fossil record through successive years of discovery.
So I read the paper, and it's pretty good. Just a few nitpicky errors (it's not, but other than that, it's fascinating and insightful. Obviously, we have some (significant) ideological disagreements, but I think Phil has treated me and my work with more intelligence and respect than some of my fellow creationists. I wish more encounters between creationists and evolutionists could be as cordial. It must have been hard to get such a paper past the reviewers and editors of ... well, any scientific journal, so I'm doubly pleased with Phil's efforts.

Regarding the paper itself, for several years I've been collecting versions of the data matrix that Phil used in his paper, with the intention of tackling the baraminology of feathered dinosaurs. Paul Garner and I recently discussed a broader dinosaur baraminology project, but that is currently on hold (while we clear our schedules of other, more pressing projects). So maybe I should adjust my schedule? I think a formal response of some kind is in order. Phil was kind enough to write and publish his paper, and I feel like I should reciprocate in some way.

This paper does remind me of some broader reflections on baraminology I was pondering yesterday after receiving a good question about sediba from a colleague in Canada. At the end of the day, statistical baraminology (in the form of baraminic distance correlation and multidimensional scaling) is really untried. It's basically going back to assertions made by Frank Marsh in Evolution, Creation and Science:
...discontinuity between kinds was just as great at their first appearance as it is today (p. 163).
There's really no biblical necessity to Marsh's claim that "created kinds" are marked off by significant morphological discontinuity. So over the past few years, I've begun to view statistical baraminology as a kind of test of Marsh's claim. I retain my enthusiasm for it as the preferred creationist method for identifying baramins, but I'm certainly prepared to go to a different method (or even different way of thinking about baramins altogether) should the need arise.

Related to this point is Senter's clever use of time-adjusted taxon sets, where he included only taxa known at certain time points (six taxa known in 1920, 12 in 1980, 14 in 1990, 21 in 2000, and 33 in 2009). He observes,
Even so, it is important to note that, as shown in Fig. 2, morphological continuity between nonavian coelurosaurs and basal birds was not established until the discoveries of the most recent two decades. Before then, creationist insistence that the known fossil record did not contain a continuous morphological sequence from nonavian coelurosaurs to birds (e.g. Gish, 1995; Lutz, 1995) was correct. Until the most recent two decades, large enough morphological gaps existed between major coelurosaurian groups for a case to be made that each was a separate 'created kind'. ... A morphological difference exists between every pair of taxa, but the transition from coelurosaurian dinosaurs to birds is no longer represented by a large enough morphological gap to support a claim of separate creation. Coelurosauria is not the only clade in which significant morphological gaps have recently been filled by new fossil discoveries. The same has recently occurred with basal chordates (Shu et al., 1999; Mallatt & Chen, 2003), basal bony fishes (Zhu et al., 2009), the fish-to-tetrapod series (Boisvert, 2005; Daeschler et al., 2006; Long et al., 2006), basal turtles (Li et al., 2008), Mesozoic mammals (Ji et al., 1999, 2002; Luo et al., 2003) and other taxa.
What? No love for the hominids? He continues:
Gaps are expected in the fossil record, because fossilization is rare. Given this, the recent explosion in the filling of fossil gaps should give creationists pause, for any such gap-filling is a serious challenge to creation science.
This is definitely a concern. A serious concern. As I wrote to my friend yesterday about hominids,
Actually, I was afraid garhi and anamensis would fall in that central gap between Paranthropus, Homo+africanus, and afarensis. Then the sediba paper came out with its dataset, and garhi grouped with afarensis. Phew! Now it's just anamensis haunting me. The real question is what addition of anamensis (or any future australopith discovery for that matter) will do to the correlations. I could imagine anamensis falling in the gap, but then the correlations just collapse into nothing (kind of like the last two datasets I described in my paper). So you can't tell what groups with what. Worst case scenario would be a string of positive correlations between sapiens and something obviously ape, like chimps or Paranthropus. That would be problematic....
Problematic indeed, but it hasn't happened yet, so we'll cross that bridge when if we come to it.

In the meantime, thanks, Phil, for a very interesting and provocative paper! I'm eager to look at your data to evaluate your findings and conclusions.

Senter. 2010. Using creation science to demonstrate evolution: application of a creationist method for visualizing gaps in the fossil record to a phylogenetic study of coelurosaurian dinosaurs. Journal of Evolutionary Biology DOI 10.1111/j.1420-9101.2010.02039.x

Feedback? Email me at toddcharleswood [at] gmail [dot] com.