The evolution of biogeochemical recycling by persistence-based selection
Richard A. Boyle, Timothy M. Lenton
Abstract
Abstract Darwinian evolution operates at more restricted scales than the feedback processes within the Earth system, precluding the development of any systematic relationship between the organism-level traits favored by natural selection and the impact of these traits upon Earth’s long-term average habitability for life. “It’s-the-song-not-the-singer” theory proposes an extended understanding of natural selection to encompass differential persistence of non-replicating entities, potentially allowing for a quasi-Darwinian understanding of biogeochemical cycles. Here we use a simple stochastic model to demonstrate how persistence selection of the form invoked by “It’s-the-song-not-the-singer” can stabilize a generic nutrient recycling loop, despite its dependence upon genotypes with relatively low organism-level fitness. We present an evolutionary trajectory plausibly representative of aspects of Precambrian biogeochemical cycles, involving persistence-based selection for recycling via fluctuations in abiotic boundary conditions and strong genetic drift. We illustrate how self-perpetuating life-environment correlation patterns, as opposed to specific state-values, may help empirically distinguish “It’s-the-song-not-the-singer” from conventional Earth-system feedbacks.