A Chemostat Model for Evolution by Persistence: Clade Selection and Its Explanatory Autonomy

Abstract

Many contemporary biologists and philosophers of biology admit that selection occurs at any level of the biological hierarchy at which entities showing heritable variation in fitness are found, while insisting that fitness at any level entails differential reproduction, not differential persistence. Those who allow that persistence can be selected doubt that selection on non-reproducing entities can be reiterated, to produce “complex adaptations”. We present here a verbal model of sub-clones evolving in a simple idealized chemostat that calls into question these suppositions and is usefully explanatory when taken as an analogy to selection for persistence of clades.

Towards a More General Theory of Evolution by Natural Selection: A Manifesto

“…His insights ground powerful alternative approaches to evolutionary phenomena that a more traditional take reduces to differential reproductive output. For example, clade selection (Doolittle 2019;Neto and Doolittle 2022) or selection on clonal entities like quaking aspens (Bouchard 2008) could be conceived in this light.…”

“…The perennial problem with such situations is that the population will necessarily dwindle (with the most persistent entities increasing their proportion in the population, as the less persistent ones perish). While this certainly is ENS, it may indeed take further mechanisms for selection to produce complex adaptations (Papale 2021;Neto and Doolittle 2022). While we wish here to focus on (2) and do so below, it is important to note that (3) is also an option: increase in the number of interactors is not strictly required for ENS to obtain (Van Valen 1989).…”

“…Some of these properties are mentioned inNeto and Doolittle (2022). Of course, one might argue that all properties of higher-level entities have their ultimate cause in properties of the lower-level entities of which they are composed (a thoroughgoing reductionist position) and thus causation and selection (if seen as a causal process) always reside at the lowest level.…”