Growing Old: Biological and Physiological Aging.

Although from an outward perspective many of the physical signs of aging may be obvious, the underlying biological mechanisms of the aging process that cause these observable changes are still not well understood. There are two general approaches taken in biological theories of aging. Genetic or programmed theories posit that aging is caused by the programmed actions of specific inherited genes. Stochastic theories posit that random assaults from the external environment and one's body accumulate over time and result in aging. Stochastic theories include the somatic mutation theory, error catastrophe theory, metabolic theory, free radical theory, and cross linkage theory of aging. As with nature/nurture controversies in psychology, however, it is more than likely that both genetic and stochastic factors play a part in the aging process. In addition, research has found some steps that can be taken to increase one's longevity and stave off the effects of the aging process.