Entropy and the arrow of time in population dynamics

The concept of entropy in statistical physics is related to the existence of irreversible macroscopic processes. In this work, we explore a recently introduced entropy formula for a class of stochastic processes with more than one absorbing state that is extensively used in population genetics models. We will consider the Moran process as a paradigm for this class, and will extend our discussion to other models outside this class. We will also discuss the relation between non-extensive entropies in physics and epistasis (i.e., when the effects of different alleles are not independent) and the role of symmetries in population genetic models. •We use statistical mechanics techniques to study population dynamics.•Biological evolution is modelled by agent interaction (microscopic laws).•We are concerned by macroscopic variables (population state).•We explore a recently introduced formula for entropy for processes with absorption.•We discuss why population dynamics exhibit macroscopic irreversibility.