An evolutionary model for simple ecosystems

TL;DR

This paper reviews simple models of asexual populations evolving on smooth landscapes, analyzing their dynamics, equilibrium properties, and phenomena like mutational meltdown and speciation, using cellular automaton models and statistical mechanics analogies.

Contribution

It introduces a simplified cellular automaton model to study evolution, mutational effects, and coexistence in asexual populations, linking these to statistical mechanics concepts.

Findings

Conditions for mutational meltdown and error thresholds identified.

Criteria for coexistence and speciation in asexual populations established.

Analysis of quasi-species shape and coexistence conditions provided.

Abstract

In this review some simple models of asexual populations evolving on smooth landscapes are studied. The basic model is based on a cellular automaton, which is analyzed here in the spatial mean-field limit. Firstly, the evolution on a fixed fitness landscape is considered. The correspondence between the time evolution of the population and equilibrium properties of a statistical mechanics system is investigated, finding the limits for which this mapping holds. The mutational meltdown, Eigen's error threshold and Muller's ratchet phenomena are studied in the framework of a simplified model. Finally, the shape of a quasi-species and the condition of coexistence of multiple species in a static fitness landscape are analyzed. In the second part, these results are applied to the study of the coexistence of quasi-species in the presence of competition, obtaining the conditions for a robust speciation effect in asexual populations.