2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/18185A simple evolutionary model for biological ageing is modified such that it requires a minimum population for survival, like in human society. This social effect leads to a transition between extinction and survival of the species.8 pages including 4 figures, Experimental GerontologyStatistical MechanicsDisordered Systems and Neural NetworksQuantitative Biologytext