MOULDING OF SENESCENCE BY NATURAL SELECTION
MOULDING OF SENESCENCE BY NATURAL SELECTION
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DOI：
10.1016/0022-5193(66)90184-6
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发表时间：
1966-01-01
影响因子：
2
通讯作者：
HAMILTON, WD
中科院分区：
文献类型：
--
作者：
HAMILTON, WD
通过数学公式推导出了几种类型的特定年龄对死亡率的小影响对适应度的影响。一种特定形式的效应，在它发生得较早时，总是有一个较大的后果，或者至少有一个同样大的后果。通过参考一个模型，其中死亡率是恒定的，它表明，这种影响是无法避免的任何可以想象的有机体。衰老是进化的必然结果这一理论的基础就这样建立起来了。这个简单的理论不能解释特别高的婴儿死亡率。费舍尔的“生殖价值”的形式在这一点上引起了错误的意见，但事实证明，它与情况没有直接关系。当一个婴儿的过早死亡使得近亲的出生或存活更有可能时，婴儿死亡率可能发生变化。同样地，当年老的动物仍然有益于其年轻的亲戚时，繁殖后的寿命可能会发生变化。该模型表明，较高的生育率将是导致较高衰老率的主要因素，除非由此产生的额外死亡率仅限于不成熟期。一些更一般性的分析说明修改生殖时间表的后果。并简要讨论了其在种群连续波动中的应用。除了这样的物种，有人认为，一般平稳的人口可以假设，在这种情况下，测量的后果，以适应性的后代的数值期望的后果是合理的。文中所讨论的年龄函数均以1906年台湾人寿命表的曲线图表示，并说明了计算方法。
The consequences to fitness of several types of small age-specific effects on mortality are formulated mathematically. An effect of given form always has a larger consequence, or at least one as large, when it occurs earlier. By reference to a model in which mortality is constant it is shown that this implication cannot be avoided by any conceivable organism. A basis for the theory that senescence is an inevitable outcome of evolution is thus established. The simple theory cannot explain specially high infant mortalities. Fisher'' s" reproductive value", the form of which gave rise to an erroneous opinion on this point, is shown to be not directly relevant to the situation. Infant mortality may evolve when the early death of one infant makes more likely the creation or survival of a close relative. Similarly, post-reproductive life-spans may evolve when the old animal still benefits its younger relatives. The model shows that higher fertility will be a primary factor leading to the evolution of higher rates of senescence unless the resulting extra mortality is confined to the immature period. Some more general analytical notes on the consequences of modifications to the reproductive schedule are given. Applications to species with populations in continual fluctuation are briefly discussed. Such species apart, it is argued that general stationary of population can be assumed, in which case the measurement of consequences to fitness in terms of consequences to numerical expectation of offspring is justified. All the age-functions discussed are illustrated by graphs derived from the life-table of the Taiwanese about 1906, and the method of computation is shown.