I’m not sure about that. Evolution has two mechanisms: mutation to roll the dice for new traits, and natural selection against any traits that hinder survival up to the point of successful reproduction.
Because this ovarian trait only manifests well after reproductive function it cannot be explained by selection pressure; the remaining culprit would be happy mutation.
Yet while every post-reproductive trait is free to vary without selection, but this one appears to be unvaried across the entire class Mammalia. What force would preserve a non reproductively-advantageous trait so broadly?
I’m not sure about that. Evolution has two mechanisms: mutation to roll the dice for new traits, and natural selection against any traits that hinder survival up to the point of successful reproduction.
Because this ovarian trait only manifests well after reproductive function it cannot be explained by selection pressure; the remaining culprit would be happy mutation.
Yet while every post-reproductive trait is free to vary without selection, but this one appears to be unvaried across the entire class Mammalia. What force would preserve a non reproductively-advantageous trait so broadly?