Stoch-aptation: a new term in evolutionary biology and paleontology

Abstract

Following two seminal papers published in the journal Paleobiology by Stephen Jay Gould and Elisabeth Vrba several decades ago, I suggest a new term (stoch-aptation) to refer to those individual traits or sets of traits that provide, just by chance, fitness adventages to species when faced with catastrophes (i.e. geological events triggering massive mortality), and that may lead to the origin of taxonomical entities above the species level. I provide as an example of stoch-aptations the set of features that helped mammals pass the Cretaceous-Paleogene transition, as well as traits behind the success of living fossils. However, the identification of specific stoch-aptations can be difficult. This missing term is necessary and useful to (a) consolidate the idea of selection at different hierarchical levels, (b) acknowledge the role of chance in the evolution of higher taxonomical categories and (c) think of the role of geological catastrophes as generators of innovation.