11. What does evolution select with regard to aging?

Selection acts on traits that improve fitness, and anti-aging processes are selected insofar as they support survival and reproduction in the relevant ecological niche. Because selection pressure generally declines with age, late-life protection is typically weak, although it can be strong in species where late survival increases lifetime reproductive success. Organisms and their functions do not evolve to age; they evolve under a compromise between performance, reproduction, and maintenance, which sets the pace and composition of the deleteriome. This framing helps explain why long-lived species invest heavily in maintenance, and why known longevity interventions often look like metabolism remodeling interventions that alter how damage is produced, handled, and tolerated, ultimately shifting the composition of the deleteriome.