The Evolutionary 16: Shaping a New Evolutionary Synthesis While Keeping the Looneys at Bay

Article excerpt

EVERY MATURE FIELD OF SCIENCE IS characterized by an established conceptual framework--what philosopher of science Thomas Kuhn called a "paradigm." Every now and then, according to Kuhn, scientists encounter a series of problems that cannot be resolved within the current paradigm. If this situation persists, a crisis eventually ensues, which is resolved by abandoning the reigning paradigm and embracing a new one.

The history of science, however, teaches us that things are not always that tidy. Biology, for instance, arguably has never undergone a paradigm shift since Darwin, although the Darwinian revolution does count as an entirely new paradigm when compared to William Paley's intelligent design-based explanations for the diversity of life. Rather, the original "Darwinism" of the mid-19th century with its twin concepts of common descent and natural selection was improved by the so-called neo-Darwinism of the late 19th century which eliminated any remaining vestiges of Lamarckism--the idea that environmentally-induced characters can be inherited. The first decades of the 20th century saw another marked expansion of evolutionary theory, which came to be known as the "Modern Synthesis'--a complex theoretical structure that reconciled the basic Darwinian ideas with the then new fields of Mendelian and statistical genetics.

The Modern Synthesis was arguably completed during the 1940s, with the publication of a series of seminal volumes by some of the preeminent evolutionary biologists of the time, including Theodosius Dobzhansky, Ernst Mayr, and George Gaylord Simpson. To this date, graduate level textbooks are built around the same conceptual structures laid out by the Modern Synthesis, although of course much has happened in biology since: the molecular revolution, the rebirth of the study of the evolution of development ("evo-devo") and the genomic era, to name a few. The question has therefore been posed by several people over the past decade or so: do we need an Extended Evolutionary Synthesis? Stephen Jay Gould among others thought so, and he tried to articulate one in his last technical book, The Structure of Evolutionary Theory.

To further explore the nature of a possible Extended Evolutionary Synthesis, Gerd Muller and I recently hosted a workshop on the current status of evolutionary theory at the Konrad Lorenz Institute for Evolution and Cognition Research, in Altenberg near Vienna, Austria. We invited 16 people who have been active in discussions of this kind and asked them to talk about where they think evolutionary biology is going. The so-called "Altenberg 16" are: John Beatty (University of British Columbia), Wemer Callebaut (University of Hasselt), Sergey Gavrilets (University of Tennessee), Eva Jablonka (Tel Aviv University), David Jablonski (University of Chicago), Marc Kirschner (Harvard University), Alan Love (University of Minnesota), Gerd Muller (University of Vienna), Stuart Newman (New York Medical College), John Odling-Smee (Oxford University), Massimo Pigliucci (Stony Brook University), Michael Purugganan (New York University), Eors Szathmary (Collegium Budapest), Gunter Wagner (Yale University), David Sloan Wilson (Binghamton University), and Greg Wray (Duke University).

In order to appreciate what we did in Altenberg, however, one first needs to understand the Modern Synthesis. At the beginning of the 20th century, standard Darwinian theory was in a bit of a crisis because it seemed incompatible with the rediscovery of Mendelian genetics, which in turn seemed hard to reconcile with statistical genetics (what today is called quantitative genetics). The new Mendelian genetics seemed to show that traits are controlled by discrete units (the genes) which would produce only discrete phenotypes. This was contrary to the requirement of continuous variation on which Darwin had built his gradualistic theory, as well as to the work being carried out by statistical geneticists (termed biometricians), who were interested in characters that display the typical bell curve, or continuous distribution. …