Making Sense of Evolution in an Uncertain World
Many organisms have adapted to alife with uncertainties. For instance,some pathogenic bacteria havegenes that can be switched off to stop diseaseprogression in a host organism or preventtheir recognition by an immune system.Such strategies increase an organism'sreproductive success and tend to be found inenvironments in which the conditions arestrongly fluctuating. To understand thedevelopment of such strategies, evolutionarybiologists determine the long-run reproductivesuccess of organisms in fluctuatingenvironments by calculating the Lyapunovexponent, a measure of the average exponentialgrowth rate in an unpredictableenvironment. Often these calculations areferociously difficult and rarely lead to simpleresults.