Massimo Pigliucci

The theory of evolution, which provides the conceptual framework for all modern research in organismal biology and informs research in molecular biology, has gone through several stages of expansion and refinement. Darwin and Wallace (1858) of course proposed the original idea, centering on the twin concepts of natural selection and common descent. Shortly thereafter, Wallace and August Weismann worked toward the complete elimination of any Lamarckian vestiges from the theory, leaning in particular on Weismann’s (1893) concept of the separation of soma and germ, resulting in what is sometimes referred to as “neo-Darwinism”. The theory then experienced a period of “eclipse” (Bowler, 1983) during which many biologists accepted the idea of common descent but either rejected or greatly diminished the importance of natural selection as an evolutionary mechanism. This situation was exacerbated by the rediscovery of Mendel’s work, given the apparent incompatibility of inheritance particles affecting discrete characters with the type of continuous quantitative variation necessary for natural selection to produce gradualistic evolutionary change. Famously, the crisis was overcome with the reconciliation of Mendelian and statistical genetics made possible by Fisher, Haldane and Wright (Fisher, 1930; Wright, 1931; Haldane, 1932), among others, and that later on culminated in the Modern Synthesis (henceforth, MS) to which several additional authors made important contributions, including but not limited to Dobzhansky, Huxley, Mayr, and Simpson (Dobzhansky, 1937; Huxley, 1942; Mayr, 1942; Simpson, 1944). The MS is still the version of the theory largely accepted by the scientific community, and it is what graduate students in the discipline are trained on (Futuyma, 1997). More recently, several authors have pushed for an Extended Synthesis (henceforth, ES) in evolutionary biology, initially from a variety of individual perspectives largely rooted in particular fields of inquiry, such as Evo-Devo MASSIMO PIGLIUCCI *