LIFE TABLES FOR NATURAL POPULATIONS OF ANIMALS
LIFE TABLES FOR NATURAL POPULATIONS OF ANIMALS
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DOI：
10.1086/395888
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发表时间：
1947-01-01
影响因子：
6.5
通讯作者：
DEEVEY, ES
中科院分区：
文献类型：
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作者：
DEEVEY, ES
本研究的材料可从多个人群中获得。人们试图将这些信息浓缩成生命表，在每个年龄段中列出1000人的初始队列中的死亡人数、幸存者人数、死亡率和预期寿命。根据收集信息的方法，spp。研究分为3组：（a）死亡年龄已知的，具有相当的准确性（Dall山羊，轮虫Floxcularia conifera，和几个物种）。鸟）;（B）在一定数量中幸存者的数量很少被直接观察到的（藤壶、歌雀、野鸡）;（c）种群的年龄结构在特定时间被观察到，死亡年龄是从类之间的收缩推断出来的（鸬鹚、许多鱼、长须鲸）。当各年龄组死亡率为常数时，存活率lx曲线在半对数坐标纸上呈对角线。这种曲线在许多鸟类身上都能找到。平均寿命每百百分位数的死亡率为320 ‰。如果在生命的最初几年观察到的恒定年龄特定死亡率真的在整个生命中保持不变，那么在1000只鸟的队列中，最老的鸟的寿命是平均寿命的6.6倍。鸟.并非所有的动物在这方面都像鸟。有些物种似乎已经进化出了一种机制，可以将平均寿命延长到最长，比如人类。还无法实现最年轻的年龄是人们所知最少的年龄，生态学家应该把精力集中在生命周期的这一部分。
Materials for this study are available from several populations. Attempts are made to condense this information into life tables, snowing for each age interval the number of deaths, number of survivors, the mortality rate, and the expectation of further life of members of an initial cohort of 1000 individuals. According to the methods used in collecting the information, the spp. studied fall into 3 groups: (a) those in which the age at death is known, with fair accuracy (Dall mountain sheep, the rotifer Floxcularia conifera, and several spp. of birds); (b) those in which the number of survivors out of a definite number has been directly observed at infrequent intervals (barnacles, song sparrow, pheasant); (c) those in which the age structure of the population is observed at a specified time, and the age of death is inferred from the shrinkage between classes (cormorant, many fish, fin whale). When mortality rate of all ages is constant, the survivorship lx curve is diagonal on semi-logarithmic graph paper. Such a curve is found for many birds. The mortality rate is 320 per thousand per hundred centiles of mean life span. If the constant age-specific mortality rate observed for the first few years of life is really maintained throughout life, the oldest bird in a cohort of 1000 lives 6.6 times as long as the avg. bird. Not all animals resemble birds in this respect. Some seem to have evolved a mechanism for stretching the mean life span toward the maximum, like man. Comparisons between spp. cannot yet be made. The youngest ages are those about which least is known, and ecologists should concentrate their efforts on this segment of the life span.