In adaptationist scenarios, traits are selected for if they are positively corre-lated with reproductive success (Fisher, 1930; Price, 1970). It seems counter-intuitive, then, that natural selection would select for a dampening, or complete cessation, of reproductive ability before the end of the somatic lifespan. If the production of offspring is a means by which favorable traits can be passed to future generations, then the continued production of offspring – even the costli-est of offspring – would seem to be beneficial. Why was there a phylogenetic shift in female reproductive strategy away from continued egg production in fish, amphibians, and reptiles, to a finite number of eggs that slowly dwin-dles across the lifespan to the point, in some mammalian species, of follicular exhaustion and low levels of ovarian hormones prior to death? In other words, why is there a menopause?
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