Evolutionary significance of ageing in the wild.

Evolutionary significance of ageing in the wild. Exp Gerontol. 2015 Aug 17; Authors: Kowald A, Kirkwood TB Abstract Human lifespan has risen dramatically over the last 150years, leading to a significant increase in the fraction of aged people in the population. Until recently it was believed that this contrasted strongly with the situation in wild populations of animals, where the likelihood of encountering demonstrably senescent individuals was believed to be negligible. Over recent years, however, a series of field studies has appeared that shows ageing can also be observed for many species in the wild. We discuss here the relevance of this finding for the different evolutionary theories of ageing, since it has been claimed that ageing in the wild is incompatible with the so-called non-adaptive (non-programmed) theories, i.e. those in which ageing is presumed not to offer a direct selection benefit. We show that a certain proportion of aged individuals in the population is fully compatible with the antagonistic pleiotropy and the disposable soma theories, while it is difficult to reconcile with the mutation accumulation theory. We also quantify the costs of ageing using life history data from recent field studies and a range of possible metrics. We discuss the merits and problems of the different metrics and show that in general longer lived species seem to carry a higher burden caused by the ageing process. PMID: 26292149 ...
Source: Experimental Gerontology - Category: Geriatrics Authors: Tags: Exp Gerontol Source Type: research