Grandmothering drives the evolution of longevity in a probabilistic model.

Bibliographic Collection: 
APE, CARTA-Inspired Publication
Publication Type: Journal Article
Authors: Kim, Peter S; McQueen, John S; Coxworth, James E; Hawkes, Kristen
Year of Publication: 2014
Journal: Journal of Theoretical Biology
Volume: 353
Pagination: 84-94
Date Published: 2014 Jul 21
Publication Language: eng
ISSN: 1095-8541
Keywords: Adult, Age Factors, Biological Evolution, Family, Female, Fertility, Humans, Longevity, Male, Models, Biological, Models, Statistical, Sexual Maturation, Time Factors, Weaning

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.

DOI: 10.1016/j.jtbi.2014.03.011
Alternate Journal: J. Theor. Biol.