Riggs J E
Departments of Neurology, West Virginia University School of Medicine, Morgantown, USA.
Mech Ageing Dev. 1996 Jun 7;87(2):91-8. doi: 10.1016/0047-6374(96)01698-3.
Evidence for natural selection is typically sought by searching for changes in organisms over generations (that is, evolution). However, evolution may represent but one biological manifestation of the force of natural selection. Although its evolutionary influence diminishes with aging, natural selection might also impact upon the manifestation of senescence via differential survival. Annual population estimates in the United States from 1951 to 1990 for age groups over 60 years old were analyzed. The rate of increase in the size of these age groups increased with increasing age. Since birth rates in developed countries have declined, this finding is a direct manifestation of differential survival over time. Correspondingly, increasing mortality rates from many disorders associated with senescence have been shown to be correlated with increasing age group population size. These observations suggest that natural selection, via differential survival, has had a demonstrable impact upon manifestation rates of the disorders of senescence.
自然选择的证据通常是通过寻找生物体在几代中的变化（即进化）来获取的。然而，进化可能只是自然选择力量的一种生物学表现。尽管其进化影响会随着衰老而减弱，但自然选择也可能通过差异生存影响衰老的表现。对美国1951年至1990年60岁以上年龄组的年度人口估计进行了分析。这些年龄组的规模增长率随着年龄的增长而增加。由于发达国家的出生率已经下降，这一发现是随时间差异生存的直接表现。相应地，许多与衰老相关疾病的死亡率上升已被证明与年龄组人口规模的增加相关。这些观察结果表明，自然选择通过差异生存，对衰老疾病的表现率产生了明显影响。
