The Role of Population Density and Resource Limitation in Predator/Prey-Mediated Life History Traits

小行星9419823 生活史理论预测的一个例子是，成年人的高死亡率将选择那些成熟和繁殖较早的个体，这些个体的变化将带来成本，如寿命缩短或晚年繁殖减少。 这一成本被生命早期成功生殖的可能性增加所抵消，因为面对高死亡率，活到老年的可能性很小。 因此，生命史进化理论也对衰老和寿命的进化做出了预测。 由于该理论所依据的性质和假设是非常普遍的，因此预测也是普遍的，并将适用于包括人类在内的多种生物。 它们还在渔业管理等领域提供了重要的见解，因为这种资源开发的后果是死亡率上升。 这种增长将不可避免地选择被开发种群中的不良特征，例如成熟期较早，规模较小。 雷兹尼克博士已经证明，来自高捕食地区的鱼类死亡率是高捕食地区的两倍。 它们成熟的年龄也较早，体型较小，比低捕食区的后代多。 这些结果都与理论预测相一致。 正在进行的四个实验正在评估这些特征，要么增加捕食者低捕食网站或引入猎物从高捕食网站低捕食网站，以前缺乏他们。 迄今为止的进展表明，这些特征与预测的一样。 当与其他数据相结合时，例如世代时间的估计和这些性状的遗传力，也可以评估自然界的潜在变化率。 这显然比以前认为的要大得多，在很大程度上是因为这种先前的推断主要是基于化石记录。

9419823 REZNICK One example of a prediction from life history theory is that high adult mortality rates will select for individuals that mature and reproduce earlier in change will carry costs, such as reduced life span or reduced reproduction late in life. This cost is offset by an increase in the probability of successful reproduction early in life, since the odds of living to an advanced age in the face of a high mortality rate are poor. The theory of life history evolution thus also makes predictions about the evolution of aging and life span. Because the properties and assumptions that underlie the theory are very general, the predictions are also general and will apply to a diversity of organisms, including humans. They also provide important insight in areas such as fisheries management, since a consequence of such resource exploitation is an increase in mortality rates. Such increases will inevitably select for undesirable features in exploited populations, such as earlier maturity at a smaller size. Dr. Reznick has shown that fish from high predation localities have mortality rates that are twice as great. They also mature at an earlier age, smaller size, and produce more offspring than those from low predation localities. These results are all consistent with theoretical predictions. Four experiments in progress are evaluating these traits by either adding predators to low predation sites or introducing prey from high predation sites to low predation sites that previously lacked them. Progress to date indicates that these traits are as predicted. When combined with other data, such as estimates of generation time and the heritability of these traits, it is also possible to evaluate the potential rate of change in nature. It is clearly far greater than previously thought, in large part because such prior inferences were based primarily on the fossil record.