DUAL HIERARCHY THEORY AND THE ENDURING LEGACY OF PUNCTUATED EQUILIBRIUM

The original Punctuated Equilibrium paper began a scientific revolution within the field of paleontology, opening the possibility for an explosion of new paleobiological research. By demonstrating the reality of evolutionary stasis, the paper also showed that the patterns paleontologists had observed in the fossil record, which sometimes conflicted with neoontological studies, could not be explained solely by poor preservation. Rather, the data provided from the fossil record suggested that some disconnect existed between processes operating at the level of individual populations and the processes operating at the level of the species. This discovery eventually led to the formation of the nested dual hierarchical model of biological organization (Eldredge and Salthe 1984, Vrba and Eldredge 1984), which built off previous work on ecological hierarchies, as well as advancements in the field of chaos theory, to, in part, explain the source of this disconnect while reconciling modern and fossil studies within a unified understanding of biological theory. The model provided a framework which could explain the existence of emergent properties at high hierarchical levels than the population while not conflicting with evolution through natural selection. In this talk we will discuss the historical importance of the dual hierarchy model and demonstrate the enduring utility of this model to tackling important questions in biological research today.