The evolution of biogeochemical recycling by persistence-based selection

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.