Modes of competition and the fitness of evolved populations

TL;DR

This paper investigates how different modes of competition influence the evolutionary fitness of species, revealing that direct competition promotes optimal fitness while resource-mediated competition can stabilize less fit species due to demographic noise.

Contribution

It demonstrates through theoretical and simulation analysis that competition mode critically affects species fitness outcomes in evolving populations.

Findings

Direct competition leads to maximally fit species distributions.

Resource-mediated competition stabilizes species with near-minimal fitness.

Demographic noise influences species stability under resource competition.

Abstract

Competition between individuals drives the evolution of whole species. Although the fittest individuals survive the longest and produce the most offspring, in some circumstances the resulting species may not be optimally fit. Here, using theoretical analysis and stochastic simulations of a simple model ecology, we show how the mode of competition can profoundly affect the fitness of evolved species. When individuals compete directly with one another, the adaptive dynamics framework provides accurate predictions for the number and distribution of species, which occupy positions of maximal fitness. By contrast, if competition is mediated by the consumption of a common resource then demographic noise leads to the stabilization of species with near minimal fitness.