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Self-preservation is a behavior that ensures the survival of an organism.〔http://www.thefreedictionary.com/self-preservation〕 It is almost universal among living organisms. Pain and fear are parts of this mechanism. Pain motivates the individual to withdraw from damaging situations, to protect a damaged body part while it heals, and to avoid similar experiences in the future. Most pain resolves promptly once the painful stimulus is removed and the body has healed, but sometimes pain persists despite removal of the stimulus and apparent healing of the body; and sometimes pain arises in the absence of any detectable stimulus, damage or disease. Fear causes the organism to seek safety and may cause a release of adrenaline, which has the effect of increased strength and heightened senses such as hearing, smell, and sight. Self-preservation may also be interpreted figuratively; in regard to the coping mechanisms one needs to prevent emotional trauma from distorting the mind (see: defence mechanism.) Even the most simple of living organisms (for example, the single-celled bacteria) are typically under intense selective pressure to evolve a response to avoid a damaging environment, if such an environment exists. Organisms also evolve while adapting - even thriving - in a benign environment (for example, a marine sponge modifies its structure in response to current changes, in order to better absorb and process nutrients). Self-preservation is therefore an almost universal hallmark of life. However, when introduced to a novel threat, many species will have a self-preservation response either too specialised, or not specialised enough, to cope with that particular threat. An example is the dodo, which evolved in the absence of natural predators and hence lacked an appropriate, general self-preservation response to heavy predation by humans and rats, showing no fear of them. ==See also== * Antipredator adaptation * Conatus * Dear enemy recognition * Fight-or-flight response (in animals) * Fight-or-flight response (in humans) * Outline of self * Death – result of failure to survive * * Outline of death – topic tree of the subjects related to the end of life 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「Self-preservation」の詳細全文を読む スポンサード リンク
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