Abstract
An individual's advantage often conflicts with the good of its group, as when an allele spreads by meiotic drive through a population whose death rate it increases, or when an asexual genotype derives immediate advantage at the expense of future adaptability. We show how selection within populations may reconcile individual and group advantage, as in the evolution of "honest meioses" resistant to segregation distortion, and the avoidance of the "cost of sex." Selection between species, whose evolutionary importance we document, presumably favors the survival and multiplication of species whose genetic systems or social organizations favor the evolution of mechanisms reconciling individual with group advantage: in other words, species with genetic or social systems where a gene's long-term selective advantage most nearly matches its contribution to the good of the species.