ff of certain genes, with senescence being defined as time whenage- associated deficits are manifested.Endoctrine Theory. Biological clocks act through hormones to control thepace of aging.Immunological Theory. A programmed decline in immune systemfunctions leads to an increased disadvantage to infectious disease and as aresult is aging and death.Error Theories include:Wear and Tear. Cells and tissue have vital part that wear out.Rate of Living. The greater an organisms rate of oxygen basic metabolism,the shorter the life span.Cross linking. An accumulation of crossed linked proteins damage cellsand tissues, slowing down bodily process.Free Radicals. Accumulated damage caused by oxygen radicals causescells and eventually organs to stop functioning.Error Catastrophe. Damage to mechanisms that synthesize proteinsresults in faulty protein which accumulate to a level that causescatastrophic damage to cells and organs.Somatic Mutation. Genetic occur and accumulate with increasing age,causing cells to fall apart and stop working. Having read the list of theories you could gain an underrating ofwhat happens through the different processes . Like Dr. Hayfick say,Instead of asking why do we age? we should be asking why do we liveas long as we do.What is Longevity?Longevity is a term , taken from infoplease encyclopedia, denotingthe length or duration of the life of an animal or plant, often used toindicate an unusually long life.Life Span and Life ExpectancyHow long can we live? Gerontologists always mentions two kindsof life spans, Maximum Life Span and Average Life Span. Most scientistdeclare that our maximum life span is 120 years. The average life span of ahuman is the average age that is reached by members of the population. Life Expectancy is the number of years a person or individual can expect tolive, this is based upon average life spans.Average life span and life expectancy has grown dramatically inthis century. In 19...
