Adaptive consumer-resource models can explain diauxic shifts and the violation of the Competitive Exclusion Principle

This poster has been shown during the poster session of the 5th Italian Conference of Physics Students.

With this poster I have won the award for ‘‘Best poster of the Conference’’, which consisted in a nice bottle of Valpolicella Ripasso.

Abstract

Competitive ecosystems are most commonly described mathematically using MacArthur’s consumer-resource model, leading to the Competitive Exclusion Principle which limits the number of coexisting competing species to the number of available resources. Nevertheless, several empirical evidences - such as bacterial community cultures - show that this principle is violated in real ecosystems. Another experimental evidence involving microbial populations that cannot be explained in this framework is the existence of diauxic (or polyauxic) shifts in microbial growth curves. By introducing adaptive metabolic strategies whose dynamics tends to maximize species’ relative fitness, we can explain both these empirical evidences. Moreover, we show that adaptation time scales play a fundamental role in how species dynamics respond to external perturbations and volatile resources.