Happenings

So, I just found out that I’m teaching this semester, which is a comfort (money will come in, and we can eat) and a pain (I am going to Arizona in March, so we will have to sort out some guest lectures or something). The subject is philosophy of the life sciences, but the blurb covers topics I wouldn’t have put up myself:

This course looks at some of the philosophical issues arising out of the study of the life sciences-primarily biology & ecology. These issues include problems associated with the theory of evolution such as: (i) recent philosophical debate on the unit of selection; (ii) How is it possible for altruism to evolve? (iii) the role of Simpson’s paradox in accounting for such apparently maladaptive traits?; (iv) how applicable are evolutionary explanations to sociology and epistemology. The course will also look at various philosophical issues in ecology such as the problem of classifying endangered species according to their risk of extinction, & the quantification of uncertainty that’s appropriate for various management decisions. The unit should be of interest to students of philosophy & students of biology.

For an introductory class I think Simpson’s paradox is a bit complex, and I find the conservation biology stuff theoretically uninteresting and mostly a matter of social ethics. Also, the fellow who normally teaches is a whiz at decision theory, and mathematically based stuff that I’m not. But I’ll manage. The good thing about teaching this subject is that it extends my paid employment to mid-year…

In the matter of Bad Journalism in Science Press Releases, there have been a few doozies lately. One of them is this silly piece. From one study about the evolution of one characteristic (vulva morphology) in one group of organisms, and a character that rather obviously goes to fitness (without that there vulva, ain’t no roundworms gonna be born), the press release writer leaps across mighty gaps of logic to argue that this proves that evolution is deterministic, not chance. What it actually shows is a bit less dramatic than that, but we have to have the drama in the headline to get it covered, don’t we?

Another it this: actually it’s a very interesting study, and the Eureka Alert isn’t badly written, but there’s enough drama there to get the ignorant journo and her editor interested. What’s the drama? Well it turns out Darwin is wrong, see?

Researchers from the University of Sheffield, as part of an international team, have discovered the secret of why dark sheep on a remote Scottish Island are mysteriously declining, seemingly contradicting Darwin’s evolutionary theory.

Except he’s not. First the study.

The Soay sheep are unique in that they are a less derived breed than on most northern islands and Scotland in general, and that the individual sheep have been tracked now, with a couple of intermissions, since the 1960s. Yes, that’s right, individual sheep. Births, deaths, paternity and maternity, general phenotype, and recently, genetics are being used to test and learn about the nature of population genetic dynamics in a real world situation. One of the researchers gave a lovely talk about a year ago at UQ.

So the results of this particular study indicate something that on the face of it seems counterintuitive. A dark fleece has been correlated with higher survival in Soay sheep. That is, it correlates with other genes for larger body size and hence resilience against the nasty winter storms that kill off so many. Now they found that the dark fleece is not spreading in the population. That’s the apparent paradox.

What’s actually happening, as this excellent summary by Yann Klementidis explains, is that when individuals are homozygous for the linked alleles, their fitness declines, while when they are heterozygous their fitness increases, somewhat like the effects of sickle cell anemia in malarial regions is for humans. One copy, increased local fitness; two, deleterious. This is enough to prevent the alleles from going to fixation (that is, taking over that locus throughout the entire population).

Is that contrary to Darwinian evolution? Not at all. I mentioned the sickle cell case – that’s been in the textbooks for over fifty years. As Yann says “This result demonstrates the importance of understanding the genetic basis of fitness variation when making predictions about the microevolutionary consequences of selection.” Indeed.

I have a complaint to make about the use of Linnaean ranks in paleontology. Soon. Writing grants…