Definition - What does Senescence mean?
Senescence is deterioration with age and a diminishing of both biological and functional characteristics over time. There are two types of senescence: cellular and whole organism. Organismal senescence has more to do with higher death and fecundity rates in older organisms within a population. Senescence begins with germ-soma separation. This process can be delayed with decreased caloric intake of 50% in laboratory rats, with some species showing negligible senescence.
MaximumYield explains Senescence
There is quite a bit of scientific research aimed at explaining why function, reproductive success and and survival of almost all living organisms decline in old age. Self maintenance is the repair of molecular and cellular damage that occurs over time. Allocating limited resources to this kind of repair takes away from reproductive effort, and therefore, on the Darwinian fitness of an individual, or the ability to pass on his or her genes.