title: Diversity as a product of inter-specific interactions.
abstract: We demonstrate diversification rather than optimization for highly interacting organisms in a well-mixed biological system by means of a simple model of coevolution. We find the cause to be the complex network of interactions formed, allowing species that are less well adapted to an environment to succeed, instead of the 'best' species. This diversification can be considered as the construction of many coevolutionary niches by the network of interactions between species. The model predictions are discussed in relation to experimental work on dense communities of the bacteria Escherichia coli, which may coexist with their own mutants under certain conditions. We find that diversification only occurs above a certain threshold interaction strength, below which competitive exclusion occurs.
authors.affiliation: Department of Mathematics, Imperial College London, South Kensington Campus, London SW7 2AZ, UK.
authors.forename: Daniel
authors.initials: D
authors.lastname: Lawson
authors.forename: Henrik Jeldtoft
authors.initials: HJ
authors.lastname: Jensen
authors.forename: Kunihiko
authors.initials: K
authors.lastname: Kaneko
mesh_terms: D000222:Adaptation, Physiological; D000818:Animals; D044822:Biodiversity; D005075:Biological Evolution; D004926:Escherichia coli / Q000502:physiology; D008954:Models, Biological; D011157:Population Dynamics