The Evolution 2008 conference, where academic researchers from all over the world get together to share their latest data and ideas on evolutionary biology, occurred from June 20-24. I gave a short talk on the last day, but was around for the entire conference sitting through lectures, viewing posters, and schmoozing with grad students and professors late into the evening. To summarize the whole conference would be impossible, but here are a couple reflections.
Reproductive Isolation
The observation that more distantly related species tend to produce crappier offspring, if they’ll hybridize at all, was noticed well before Darwin provided a theory of evolution. It wasn’t until the 1930’s and 40’s (a period in evolutionary biology known at the Modern Synthesis) that two scientists, Theodosius Dobzhansky and Hermann Muller, provided a genetic theory to explain the phenomenon. The low viability and/or fertility of hybrids is one form of reproductive isolation. The late Ernst Mayr emphasized that reproductive isolation is the key process leading to the formation of new species, which led to what we call the Biological Species Concept (BSC). Interestingly, within the group of biologists who study the origin of new species (speciation), the BSC is king, and most of the speciation talks at Evolution focused exclusively on reproductive isolation. Among my favorites were several studies comparing the rate and ultimate causes of reproductive isolation across a large taxonomic groups (e.g. toads or monkeyflowers). These studies go beyond a single species pair to demonstrate the general processes underlying most speciation events.
Outside the speciation sessions however, the BSC and the importance of reproductive isolation are treated with more skepticism. To give one obvious example, the BSC cannot apply to asexual taxa like bacteria because they don’t mate, period. Many other ideas about what species are and how they form have been proposed, but none are very popular outside certain fields (e.g. paleontologists generally use morphology since they can’t try to mate fossils). I tend to focus on reproductive isolation, but ultimately consider myself a pluralist. But what really interests me is why, sociologically speaking, one idea of speciation can be so dominantly accepted among a small group of researchers, but remain a point of contention among the rest of the field. I don’t really have ideas at the moment – just an observation.
Ecological Niche Modeling
I am also interested in ecological niche modeling, which uses climate data from areas where species were collected to infer their entire range. There was an entire symposium dedicated to the topic at Evolution, where one of the major questions was how and how much do closely related species differ in their ecologies, if they differ at all. Much of the difficulty with the field is methodological – how well does niche modeling actually predict the range of species? It’s difficult to ask because the whole point of niche modeling is to infer the ecology without having to exhaustively sample. There were two talks on this topic that caught my eye. The first, by Joseph Bernardo, was highly critical. He laid out a bunch of fairly obvious reasons why niche modeling might often fail. However, he never bothered to reanalyze any data or provide concrete examples. It didn’t help that none of his figures showed up on the PowerPoint and he went over time despite prodding from the moderator to wrap up. Another talk by Rich Glor actually examined the robustness of niche modeling by comparing results observation rich and observation poor data sets. He found, surprisingly, that even observation poor data sets did pretty well compared to those with many observations, indicating the niche modeling may be robust to low sample size. I think there are still many potential pitfalls of ecological niche modeling, but the indications from the conference were promising.
Well, there is a lot more I could write about, but that is enough for now. Check out the website and program for more information.
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I am reading Deleuze and Guattari’s A THOUSAND PLATEAUS: CAPITALISM AND SCHIZOPHRENIA right now. They are interested in rejecting all of the grand narratives (including modernism, postmodernism, psychoanalysis, Marxism, and evolution) of the last 200 years. As such, they create a fairly elaborative framework around which to re-think evolution. They are obviously more “theoretical” than scientific. They encourage people to re-think evolution as “involution,” which is different-but-the-same. I can’t go into it here, only to tell you that it would have been an unpopular idea at that conference.