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Some species have the equivalent of many more than two sexes, but most do not. A new model suggests the reason depends on how often they mate.
How the ultra-cooperative behavior of ants, bees and other social insects could have evolved continues to challenge formal analysis. But a new theory about hedging bets against nature’s unpredictability may change the math and shift the debate.
Scientists are exploring how organisms can evolve elaborate structures without Darwinian selection.