Fluid Dynamics May Play Key Role in Evolution of Cooperation

Presented by Office of Public Affairs and Communications

Believe it or not — it’s in our nature to cooperate with one another, even when cheating may be more profitable. Social cooperation is common in every scale of life, from the simplest bacterial films and multicellular tissues to insect colonies and nation-states, where individuals prioritize the common good over personal gain, even when the two might conflict. Scientists have long wondered how social cooperation could evolve and persist, since “survival of the fittest” often favors cheaters that multiply at the expense of others.

In a new study, physicists at the University of Notre Dame examined how the mechanical properties of an environment may shape the social evolution of microbial populations. Through computer simulations and analytical calculations, they determined the necessary properties of diffusion and flow that allow microbes to evolve stable social behavior. Their findings also allow for speculation that the evolution of single-cell organisms to multicellular organisms may have taken place in flowing fluids like rivers or streams as opposed to larger bodies of water such as oceans and lakes.