Expand Or Revise? The Evolutionary Synthesis TodayEvolution: The Extended Synthesis. Edited by Massimo Pigliucci and Gerd B. Müller. Cambridge (Massachusetts): MIT Press. $35.00. viii + 495 p.; ill.; index. ISBN: 978-0-262-51367-8. 2010.

Abstract

A review of Evolution: The Extended Synthesis. Edited by Massimo Pigliucci and Gerd B. Muller. Cambridge (Massachusetts): MIT Press. $35.00. viii 495 p.; ill.; index. ISBN: 978-0-26251367-8. 2010. The “Modern Synthesis” (Huxley 1942) or “Evolutionary Synthesis” (Mayr and Provine 1980) that transpired in the 1930s and 1940s is generally considered the first major advance in evolutionary biology after Darwin’s great work. Its major accomplishments were the formulation of a theory of evolutionary processes by joining Mendelian genetics and Darwin’s theory (especially natural selection), the interpretation of the observations of paleontologists, systematists, and naturalists in terms of this theory, and the rejection of some anti-Darwinian ideas, such as neo-Lamarckism, orthogenesis, and the radical saltationism associated with Goldschmidt’s “systemic mutation” and “hopeful monsters.” The Modern Synthesis (MS) occurred before there existed any glimmering of the molecular basis of heredity, but nevertheless could later accommodate newly discovered phenomena such as transposable elements. Even today, the population genetic theory of the MS remains intact, although it is now the foundation for a greatly expanded superstructure. In contrast to genetics, development entered the MS chiefly in phenomenological terms, such as allometry and heterochrony, mostly in a macroevolutionary context. Experimental embryologists described phenomena such as gradients and induction, but hardly anything was known of the mechanisms of development, and so little could be said about the mechanistic basis of phenotypic evolution. With some notable exceptions (Collins 1986), ecology remained distant from evolutionary studies; the study of genetics and natural selection in natural populations had only just begun. Under these circumstances, the chief aim of forward-thinking evolutionary biologists had to be formulating and establishing a rigorous, genetically informed theory of evolutionary processes that could account for adaptation and speciation. During the 1950s and early 1960s, much of the research in evolutionary biology was directed toward developing evidence on major themes of the MS: documenting selection in natural populations, describing and attempting to account for genetic variation, and characterizing reproductive isolation and the geographic setting of speciation. Broad though their vision was, the architects of the MS focused on a narrower range of questions than Darwin had or than their successors would. Beginning in the 1960s, evolutionary science expanded greatly. For example, population genetics and ecology were united as “population biology,” later expanding into “evolutionary ecology” that applied evolutionary thinking to community ecology. The adaptive evolution of classes of phenotypic traits, based explicitly on individual selection, was the focus of new fields such as life-history evolution and behavioral ecology. The first steps were