Environmental stochasticity and the speed of evolution

TL;DR

This paper investigates how environmental stochasticity influences the rate of evolution in biological populations, revealing that it can either slow down or speed up evolution depending on the competition type.

Contribution

It extends existing models by incorporating environmental variations, providing theoretical and numerical insights into their impact on evolutionary speed.

Findings

Environmental stochasticity reduces evolution speed under pairwise competition.

Environmental stochasticity increases evolution speed under global competition.

Theoretical and numerical analysis of stochastic effects on evolution.

Abstract

Biological populations are subject to two types of noise: demographic stochasticity due to fluctuations in the reproductive success of individuals, and environmental variations that affect coherently the relative fitness of entire populations. The rate in which the average fitness of a community increases has been considered so far using models with pure demographic stochasticity; here we present some theoretical considerations and numerical results for the general case where environmental variations are taken into account. When the competition is pairwise, fitness fluctuations are shown to reduce the speed of evolution, while under global competition the speed increases due to environmental stochasticity.