Human Enhancement, Evolution and Lifespan: Evolving Towards Immortality?

Abstract

Life expectancies of closely related species can differ substantially from one another. Such contrasts illustrate that life expectancy is not an inert quality of a biological system, but an evolved trait. A key factor in the evolution of lifespan is the extent to which individuals of a population are subjected to mortality factors that are largely beyond their control, such as the likelihood to die from disease, predators or starvation. A well-supported prediction in this context is that ageing rate will evolve to slow down when the risk of such extrinsic mortality decreases. For evolution to occur, only a very small number of criteria need to be fulfilled, and it is argued that humans still fulfil these criteria and that contemporary human populations thus continue to evolve through natural selection. The environmental change experienced by Western human populations is such that extrinsic mortality has been decreasing for many decades. This is due to changes in the external environment (cars, houses, industrialised agriculture), but also to changes in the body itself due to better nutrition and medical interventions. Based on the preceding points, the prediction is made that when the current low extrinsic mortality rate persists, human lifespan will evolve to become even longer than it is today.

Translated by Liseth Wielema.