If ageing could evolve in one-celled organisms for the long-term good of the species, and despite its cost to the individual, then why not other forms of ageing that affect higher animals?

• 如果为了物种的长期利益，单细胞生物体可以进化出老化，可以不顾老化要个体付出代价；那么，为什么不能进化出影响高等动物的其他形式的老化？