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The somatic mutation theory of ageing states that accumulation of mutations in somatic cells is the primary cause of aging. A comparison of somatic mutation rate across several mammal species found that the total number of accumulated mutations at the end of lifespan was roughly equal across a broad range of lifespans. [ 16 ]
According to this theory, life span development has multiple trajectories (positive, negative, stable) and causes (biological, psychological, social, and cultural). Individual variation is a hallmark of this theory – not all individuals develop and age at the same rate and in the same manner. [15] Bronfenbrenner's ecological theory
The immunological theory of aging suggests that the immune system weakens as an organism ages. This makes the organism unable to fight infections and less able to destroy old and neoplastic cells. This leads to aging and will eventually lead to death. This theory of aging was developed by Roy Walford in 1969.
It is suggested instead that mutation accumulation is only one factor among many, which together form the cause of aging. In particular, the mutation accumulation theory, the antagonistic pleiotropy hypothesis and the disposable soma theory of aging are all believed to contribute in some way to senescence. [11]
Selectivity theory (aging) Socioemotional selectivity theory; Stage-crisis view; Stem cell theory of aging; Stereotype embodiment theory; T. Telomere theory of aging; V.
Aging is characterized by a progressive loss of physiological integrity, leading to impaired function and increased vulnerability to death. The hallmarks of aging are the types of biochemical changes that occur in all organisms that experience biological aging and lead to a progressive loss of physiological integrity, impaired function and, eventually, death.
In 1968 it took the form and became known as the neuroendocrine theory of aging. [38] [39] [40] 1956 Denham Harman proposed the free-radical theory of aging and demonstrated that free radical reactions contribute to the degradation of biological systems. [41] The theory is based on the ideas of Rebeca Gerschman and her colleagues put forward in ...
In gerontology, late-life mortality deceleration is the disputed theory that hazard rate increases at a decreasing rate in late life rather than increasing exponentially as in the Gompertz law. Late-life mortality deceleration is a well-established phenomenon in insects, [ 1 ] which often spend much of their lives in a constant hazard rate ...