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This is a list of the longest-living organisms that includes oldest individual bioforms. This is usually defined as: * (a) Having a longer life-span than any other known individual species (such as the Methuselah tree) OR * (b) Record Holders *, Longevity certified record-holders (such as longest lived human Jeanne Calment OR oldest lived cat Creme Puff) ==Biological immortality== (詳細はbiologically immortal. There are many examples of plants and animals for which the mortality rate actually decreases with age, for all or part of the life cycle. If the mortality rate remains constant, the rate determines the mean life-span. The life-span can be long or short, even though the species technically "does not age". * ''Sanicula'' is a herb, native to Europe and the Americas, which lives about seventy years in the wild. Old saniculae do not die at a higher rate than younger ones. * Sea urchins and some clams have relatively high rates of mortality in the ocean, but mortality does not appear to increase with age. * ''Hydras'' were observed for four years without any increase in mortality rate. Other species have been observed to regress to a larval state and regrow into adults multiple times. * The Hydrozoan species ''Turritopsis dohrnii'' is capable of cycling from a mature adult stage to an immature polyp stage and back again. This means that there may be no natural limit to its life-span. However, no single specimen has been observed for any extended period, and it is impossible to estimate the age of a specimen. * The larvae of carrion beetles have been created to undergo a degree of "reversed development" when starved, and later to grow back to the previously attained level of maturity. The cycle can be repeated many times. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「List of longest-living organisms」の詳細全文を読む スポンサード リンク
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