Kim Peter S, McQueen John S, Coxworth James E, Hawkes Kristen
School of Mathematics and Statistics, University of Sydney, NSW 2006, Australia.
Department of Anthropology, University of Utah, Salt Lake City, UT 84112, USA; Utah Population Database, University of Utah, Salt Lake City, UT 84112, USA.
J Theor Biol. 2014 Jul 21;353:84-94. doi: 10.1016/j.jtbi.2014.03.011. Epub 2014 Mar 14.
We present a mathematical model based on the Grandmother Hypothesis to simulate how human post-menopausal longevity could have evolved as ancestral grandmothers began to assist the reproductive success of younger females by provisioning grandchildren. Grandmothers׳ help would allow mothers to give birth to subsequent offspring sooner without risking the survival of existing offspring. Our model is an agent-based model (ABM), in which the population evolves according to probabilistic rules governing interactions among individuals. The model is formulated according to the Gillespie algorithm of determining the times to next events. Grandmother effects drive the population from an equilibrium representing a great-ape-like average adult lifespan in the lower twenties to a new equilibrium with a human-like average adult lifespan in the lower forties. The stochasticity of the ABM allows the possible coexistence of two locally-stable equilibria, corresponding to great-ape-like and human-like lifespans. Populations with grandmothering that escape the ancestral condition then shift to human-like lifespan, but the transition takes longer than previous models (Kim et al., 2012). Our simulations are consistent with the possibility that distinctive longevity is a feature of genus Homo that long antedated the appearance of our species.
我们提出了一个基于祖母假说的数学模型，以模拟随着祖代祖母开始通过抚养孙辈来帮助年轻女性提高生殖成功率，人类绝经后的长寿是如何演化的。祖母的帮助将使母亲能够更快地生育后续后代，而不会危及现有后代的生存。我们的模型是一个基于主体的模型（ABM），其中种群根据个体间相互作用的概率规则演化。该模型是根据确定下一个事件发生时间的 Gillespie 算法制定的。祖母效应驱使种群从代表二十出头类似大猩猩的平均成年寿命的平衡状态，转变为代表四十出头类似人类的平均成年寿命的新平衡状态。ABM 的随机性允许两种局部稳定平衡状态同时存在，分别对应类似大猩猩和类似人类的寿命。具有祖母抚养行为且脱离祖先状态的种群随后会转变为类似人类的寿命，但这种转变所需的时间比之前的模型更长（Kim 等人，2012 年）。我们的模拟结果与独特的长寿是智人属的一个特征这一可能性相一致，且这一特征在我们人类物种出现之前就已存在很久。
