Researchers have proposed a solution to a long-standing evolutionary conundrum: Why do populations of identical organisms sometimes split into two strains, cooperators and cheaters?
Cooperation and cheating, inescapable parts of human existence, also occur in a wide range of other creatures, down to the tiniest. For instance, in a yeast population, some cells produce the enzymes required to digest sugars, while other cells mooch off their enzyme-producing fellows.
Since all the yeast cells live in the same environment, why are some cooperators and others cheaters? For decades, researchers have struggled to explain how such dichotomies arise. Now, a trio of mathematicians and zoologists has proposed a model for the split.
The team assumed that the population starts out consisting of identical organisms. Each individual is capable of producing, at some cost to itself, a certain common good—such as an enzyme—that benefits both the individual and the popul