MALADAPTED BYPRODUCT. “Under Williams’ hypothesis, the evolution of aging can be seen as a maladaptive byproduct of selection for survival and reproduction during youth. A fundamental corollary of Williams’ AP hypothesis is that early fitness components such as reproduction should genetically trade-off with late fitness components such as survival at old age, so that, for example, genotypes with high early fecundity should be shorter lived than those with low reproduction.”
http://www.nature.com/scitable/knowledge/library/the-evolution-of-aging-23651151