Before hierarchy: the rise and fall of Stephen Jay Gould’s first macroevolutionary synthesis

Abstract

Few of Stephen Jay Gould's accomplishments in evolutionary biology have received more attention than his hierarchical theory of evolution, which postulates a causal discontinuity between micro- and macroevolutionary events. But Gould's hierarchical theory was his second attempt to supply a theoretical framework for macroevolutionary studies-and one he did not inaugurate until the mid-1970s. In this paper, I examine Gould's first attempt: a proposed fusion of theoretical morphology, multivariate biometry and the experimental study of adaptation in fossils. This early "macroevolutionary synthesis" was predicated on the notion that parallelism and convergence dominate the history of higher taxa, and moreover, that they can be explained in terms of adaptation leading to mechanical improvement. In this paper, I explore the origins and contents of Gould's first macroevolutionary synthesis, as well as the reasons for its downfall. In addition, I consider how various developments during the mid-1970s led Gould to identify hierarchy and constraint as the leading themes of macroevolutionary studies-and adaptation as a macroevolutionary red herring.

A Plea for a New Synthesis: From Twentieth-Century Paleobiology to Twenty-First-Century Paleontology and Back Again

“…By uncovering deep-time patterns and processes, paleontologists were indeed able to contribute to and expand the evolutionary mechanisms set during the modern synthesis of evolution. Gould coupled this theoretical aim with a broader idea of science, paleontology, and evolutionary time [ 5 , 9 , 10 , 11 ].…”

“…Gould’s idea was that evolutionary time could be seen as a system of distinct tiers—and the problem of transpacific evolution requires an explicit study of their interaction. Darwinian tradition leads us to deny this kind of structuring, to view time as a continuous, and to seek the source of causality at all scales in observable events and processes at smallest [ 9 , 18 ].…”

The Fate of the Method of ‘Paradigms’ in Paleobiology

“…This was hardly compensated by the positive impact of his emphasis, following Seilacher, on the combination of phylogenetic and fabricational ''aspects.'' The intellectual or biographical reasons for Gould's dramatic change of mind on the place of functional morphology in paleobiology remain somewhat obscure, but were certainly related in part to his changing stance in contemporary debates among evolutionary theorists, which highlighted putatively non-functional or non-adaptive aspects of morphology (Dresow, 2017).…”

“…Here he noted that since 1975, when the wellknown trio of papers by Paul, Cowen and Grant (already described here) was published, ''the problem has vanished from the literature: wrongly, for it was just this discussion that resolved many misunderstandings'' (Reif, 1981b, p. 15, my translation). The following year Reif enlarged on this ''problem'' in a paper that described functional morphology as lying uncomfortably ''on the procrustean bed of the neutralism-selectionism debate'' in evolutionary theorizing (Reif, 1982): this identified what was apparently the major factor in Gould's change of mind about the paradigm method (Dresow, 2017). Reif noted how the ''constructional'' approach to morphology, as pioneered by Seilacher, had emphasized the intrinsic constraints on the evolutionary optimizing of functional structures; at the same time, however, he identified functional inference as ''one of the most important keys to paleoauteocology,'' which in turn was ''one of the most constitutive fields of paleobiology'' (Reif, 1982, p. 53).…”