Tuesday, November 4, 2008
Extinction and evolution
Among checking on election news this afternoon during my lunch break, I found this article on the New York Times, which I thought could be of interest: http://www.nytimes.com/2008/11/04/science/04conv.html?pagewanted=1.
Namely, it is about the work that Prof. Stuart Pimm of Duke University is doing to study--and combat--the extinction of species (no, that is not Prof. Pimm in the picture, but one of the animals that he studies, the golden lion tamarin of Brazil). In studying Darwin one can read about the "tree of life," with the emphasis being on those branches of the tree that continue to evolve, but what happens to those dead-end branches that do not? Pimm's work gives current and vivid examples of such cases.
Unsurprisingly, the culprits that prevent such further evolution are often human beings, through the expansion of the human population and corresponding alteration of natural habitat, whether in the destruction of rain forests in Brazil, or the development (real-estate and agricultural)and importation of foreign species to the Hawaiian Islands, an example that Pimm discusses at the beginning of this article. When he first visited Hawaii over thirty years ago, he thought that it would harbor a rich and diverse native flora and fauna, like the Galapagos, and was disappointed at the paucity of native species (10 types of animals, with a further 10 on the brink of extinction).
Trying to think about this in Darwinian terms, I am reminded of Paul Ewald's book, "The Evolution of Infectious Diseases," which I began reading on the train this morning. One of the problems that Ewald outlines is that infectious diseases adapt more quickly than the biological beings that act as hosts for them (such as humans, animals, etc.) Using this analogy, it looks like human beings play the role of "infectious diseases" when compared to the wildlife that can't adapt quickly enough to ward off or at least adapt to our incursions.
One area of course where this analogy breaks down is that there are people like Pimm who are trying to find ways to save species, and there are no infectious diseases I know of that are trying to spare us the worst that they have to offer. If you take a look at the interview with Pimm, listen to his audio segements as well, where he discusses efforts to save the Florida panther (through importing female panthers from Texas)as well as saving the habitat of the golden lion tamarin in Brazil, purchasing land between shrinking islands of forest habitat so that "it will be possible for lonely hearts to meet members of the opposite sex and go forth and multiply."