Stephen Jay Gould’S Evolving, Hierarchical Thoughts On Stasis

Abstract

Abstract Steve Gould made so many lasting contributions to paleontology and evolutionary biology that it is hard to identify any one as most significant. It is clear, however, that his work developing punctuated equilibrium with Niles Eldredge (e.g., Eldredge, 1971; 1972e; 1977c) will rank as one of the most important. Punctuated equilibrium posits that speciation takes place relatively rapidly compared to the total duration of the species and occurs in small, isolated populations usually along the margin of the species range. Because of the relatively sudden nature of speciation and because it happens in small, isolated populations, its occurrence in the fossil record will be difficult to observe. Punctuated equilibrium also posits that throughout most of their evolutionary history species are stable, displaying what was termed morphological stasis; stasis may be punctuated equilibrium’s “most important contribution to evolutionary science” (2002c, 874). The development of punctuated equilibrium represented an important theoretical breakthrough by Eldredge and Gould made possible because each author had collected abundant data from the fossil record, and also each author had a thorough understanding of evolutionary theory. The latter was particularly important.