"The natural balance produced by the Rock, Paper, Scissors scenario is not confined to lizards. Researchers from Stanford and Yale have discovered that the same scenario is responsible for preserving biodiversity in bacterial neighborhoods. The bacteria concerned are Escherichia coli—the type that are found in all of our digestive systems. The researchers mixed three natural populations together in a petri dish. One population produced a natural antibiotic called “colicin” but was immune to its effects, as snakes are immune to poisoning by their own venom. A second population was sensitive to the colicin but could grow faster than the third population, which was resistant to colicin. The net result was that each established its own territory in the petri dish. The colicin producers could kill off any nearby bacteria that were sensitive to the colicin, the colicin-sensitive bacteria could use their faster growth rate to displace the colicin-resistant bacteria, and the resistant bacteria could in turn use their immunity to displace the colicin producers!"