The model for the emergence of a population of “cheaters” out of a population of “cooperators” described in this article gives a fresh viewpoint on existing ecosystems—and much more. Might the evolution of asymmetric modern sex from symmetric DNA exchange (like that practiced by paramecia) have been one special case of this emergence? If so, as a male, I prefer the more accurate terminology “high-investment participation” and “low-investment participation” over “cooperation” and “cheating.”

Stan Lyness
Auburndale, Mass