Reproduce and die! Why aging? Part I.
In multi-cellular organisms--and hence also in man--aging and dying is the fate of the soma, i.e., the body proper; germ cells are--at least in principle--immortal. As the soma can be considered to be the "service compartment" of the germ cells, it loses its function once a species' phase of reproduction is over. Hence, there is an intimate relationship between reproduction and aging, and therefore also between a species' reproductive strategy and aging: there has been no selection for maintenance of the soma beyond the reproductive phase of life (when there is no reproduction, there is also no natural selection). As a consequence, mechanisms, important for maintenance of the soma during the reproductive phase, increasingly begin to fail once this phase is over, resulting in an accumulation of all kinds of pathology and genetic errors, rendering an individual increasingly more prone to a variety of (internal and external) attacks. In the end, the soma collapses, be it due to organ failure, a neoplasm or to a final external push, e.g., an infection.
Schuiling
Gerard A
GA
Division of Human Biology, Faculty of Medical Sciences, University of Groningen, Groningen, The Netherlands.
D000375:Aging / Q000502:physiology*; D005075:Biological Evolution; D003643:Death; D006801:Humans; D043762:Reproductive Behavior / Q000502:physiology*