A Our life span is restricted. A 每个人的生命都是有限的， Everyone accepts this as ‘biologically’ obvious. 这一点人人都认为从生物学的角度显而易见。 ‘Nothing lives forever!’ 没有什么东西是可以永生的。 However, in this statement we think of artificially produced, technical objects, products which are subjected to natural wear and tear during use. 但这一说法让我们想到了人造产品，这些产品在使用过程中也会有磨损和消耗。 This leads to the result that at some time or other the object stops working and is unusable (‘death’ in the biological sense). 因此，在某个特定的时刻，这些物品也会停止工作，不能使用（生物学上的“死亡”）。 But are the wear and tear and loss of function of technical objects and the death of living organisms really similar or comparable? 但是这些技术类产品的磨损和功能丧失同生物的死亡真的有相似点或可比性吗？

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B Our ’dead’ products are ‘ static’, closed systems. B我们的“死亡”产品是静态的、封闭的系统。 It is always the basic material which constitutes the object and which, in the natural course of things, is worn down and becomes ‘older’. 这些产品的基本原料在自然状态下被损耗，因而变“老”。 Aging in this case must occur according to the laws of physical chemistry and of thermodynamics. 根据物理学、化学和热力学的规律，在这种情形下老化自然会发生。 Although the same law holds for a living organism, the result of this law is not inexorable in the same way. 虽然同样的规律也适合生物，但是其作用下产生的结构也不是不可改变的。 At least as long as a biological system has the ability to renew itself it could actually become older without aging; an organism is an open, dynamic system through which new material continuously flows. 至少只要生物系统有能力做自我更新，那么它实际上可以活得更长，而不是迅速老化，生物个体是一个开放的、有活力的，不断有新陈代谢的系统。 Destruction of old material and formation of new material are thus in permanent dynamic equilibrium. 因而旧物质的毁灭和新物质的产生处在一种永久的动态平衡中。 The material of which the organism is formed changes continuously. 生物内部的组成成分是不断改变的。 Thus our bodies continuously exchange old substance for new, just like a spring which more or less maintains its form and movement, but in which the water molecules are always different. 因此我们的身体需要不断地进行新陈代谢，就像一股一直保持着外在形式和运动状态的喷泉，其内部的分子却一直在变化一样。

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C Thus aging and death should not be seen as inevitable, particularly as the organism possesses many mechanisms for repair. C 因此老龄化和死亡不应该被看成是不可避免的，尤其是生物还拥有自我修复的诸多功能时。 It is not, in principle, necessary for a biological system to age and die. 理论上说，一个生物机体没有必要一定要衰老和死亡。 Nevertheless, a restricted life span, aging, and then death are basic characteristics of life. 然而，生命的有限、衰老和死亡都是其基本特征。 The reason for this is easy to recognise: in nature, the existent organisms either adapt or are regularly replaced by new types. 究其根源，是因为现存的生物要么适应环境，要么被新物种所取代。 Because of changes in the genetic material (mutations) these have new characteristics and in the course of their individual lives they are tested for optimal or better adaptation to the environmental conditions. 由于在基因组成上的变化（变异），这些生物拥有了新的特征：在它们各自的生命周期中，它们不断地被自然检验，以更好地适应环境。 Immortality would disturb this system - it needs room for new and better life. 生命的不朽会扰乱整个系统——自然界需要空间来更新物种，以便带来更好的生存方式。 This is the basic problem of evolution. 这就是进化。

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D Every organism has a life span which is highly characteristic. D 每一个有机体都拥有各自独特的生命周期。 There are striking differences in life span between different species, but within one species the parameter is relatively constant. 不同的物种，其生命周期也各不相同，但是在同一个物种内部，其寿命的参数相对是恒定的。 For example, the average duration of human life has hardly changed in thousands of years. 例如，在几千年的进化历史中人类的平均寿命的变化幅度其实很小。 Although more and more people attain an advanced age as a result of developments in medical care and better nutrition, the characteristic upper limit for most remains 80 years. 即使越来越多的人因为医疗和营养的改善寿命越来越长，但对于绝大多数人来说寿命的上限仍然是 80 岁。 A further argument against the simple wear and tear theory is the observation that the time within which organisms age lies between a few days (even a few hours for unicellular organisms) and several thousand years, as with mammoth trees. 另一个反对传统的磨损理论的论据来源于人们对其他生物的生命周期的观察，它们中有的只能存活几天（单细胞生物甚至只能活上几个小时），有的却能像巨杉一样活到几千年。

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E If a life span is a genetically determined biological characteristic, it is logically necessary to propose the existence of an internal clock, which in some way measures and controls the aging process and which finally determines death as the last step in a fixed programme. E如果寿命是一种由基因决定的生理特征，那么从逻辑上我们有必要提一下生物钟，生物钟通过某种方式测量和控制着衰老的全过程，并且最终决定该生物的死亡，就像一个固定程序中的最后一步。 Like the life span, the metabolic rate has for different organisms a fixed mathematical relationship to the body mass. 就像生命周期一样，不同生物的新陈代谢率都同生物的机体有着一种恒定的数学联系。 In comparison to the life span this relationship is ‘inverted’: the larger the organism the lower its metabolic rate. 同生命周期相比，这种联系是反向的。生物个体的体积越大，新陈代谢率就越低。 Again this relationship is valid not only for birds, but also, similarly on average within the systematic unit, for all other organisms (plants, animals, unicellular organisms). 此外，这一联系不仅适用于鸟类，对于其他的所有生物都同样适用（包括植物、动物和单细胞生物）。

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F Animals which behave ‘frugally’ with energy become particularly old, for example, crocodiles and tortoises. F以鳄鱼和乌龟为代表，在消耗能量方面较为“节约”的动物一般寿命都比较长。 Parrots and birds of prey are often held chained up. 鹦鹉和猛禽常常被擒在牢笼之中， Thus they are not able to ‘experience life’ and so they attain a high life span in captivity. 从此它们不能“消耗生命”，因而在囚禁中反而活得更长。 Animals which save energy by hibernation or lethargy (e. g. bats or hedgehogs) live much longer than those which are always active. 那些通过冬眠或沉睡来节约能量的动物（例如蝙蝠和刺猬）通常活得比那些活动较为频繁的动物更久。 The metabolic rate of mice can be reduced by a very low consumption of food (hunger diet). 老鼠的新陈代谢可以通过消耗更少量的食物来降低（饥饿饮食）， They then may live twice as long as their well fed comrades. 然后它们的寿命平均是那些比它们吃得更多更饱的动物的两倍。 Women become distinctly (about 10 per cent) older than men. 大约 10% 的女性会看上去比同龄的男性显老。 If you examine the metabolic rates of the two sexes you establish that the higher male metabolic rate roughly accounts for the lower male life span. 如果你研究一下男性和女性的新陈代谢率，你就会确定男性的高新陈代谢率是他们的平均寿命偏短的原因。 That means that they live life ‘energetically’ - more intensively, but not for as long. 这意味着男性的生活更有激情，能量强度更大，但活的时间不长。

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G It follows from the above that sparing use of energy reserves should tend to extend life. G 从上面的讨论可以看出，节约使用我们的能量储备应该可以延长寿命。 Extreme high performance sports may lead to optimal cardiovascular performance, but they quite certainly do not prolong life. 极端的剧烈运动可能会让心血管功能达到最佳状态，但肯定不会延长寿命。 Relaxation lowers metabolic rate, as does adequate sleep and in general and equable and balanced personality. 放松下来可以降低代谢率，而充足的睡眠及大体平和的性格也会起到相同的作用。 Each of us can develop his or her own ‘energy saving programme’ with a little self-observation, critical self-control and, above all, logical consistency. 只要进行一些自我观察、严格的自我控制，尤其重要的是保持逻辑连贯性，我们每个人都能发展自己的“节能程序“。 Experience will show that to live in this way not only increases the life span but is also very healthy. 经验表明这样的生活方式不仅能够延年益寿，而且非常健康。 This final aspect should not be forgotten. 最后这点绝对不要忘记。