Evolutionary theory has much to say about the evolution of single species and about the evolution of two species living in conflict or harmony with each other. Ecosystems, however, consist of many species that compete and cooperate with each other in diverse ways. These interactions may result from a number of different causes, such as protection from the elements or other species, or the use or production of limited resources. The interactions may be irregular - dependent on the environment, asymmetric, or non-transitive. For example one species may out-compete another for resources only when it is the first to colonize a particular environment; or one species may facilitate the growth of another, the second may facilitate the growth of a third, but the third have an antagonistic relationship with the first.
This project brings together two complementary approaches to evolutionary research - experimental evolution of bacteria and mathematical modeling of ecological and evolutionary dynamics - to investigate the evolution of multi-species communities. Using four bacterial species that can coexist in the laboratory, we will characterize their ecological interactions; build mathematical models of these interactions with which we will predict their evolutionary dynamics; and finally test our predictions by evolving communities consisting of one, two or four species in the laboratory. This work represents a novel direction in experimental evolution, one that will provide insight into the evolution of ecological dynamics within a community, and extend our purview beyond the interactions of just two species. An important broader impact of this project will be the training of graduate students at the interface of the mathematical and biological sciences.
