Parsons P A
Am Nat. 1993 Jul;142 Suppl 1:S5-20. doi: 10.1086/285520.
Natural populations are subjected to abiotic environmental stresses of varying intensity. Some organisms can increase their resistance to stress by a genetic reduction in metabolic rate. This relationship underlies negative associations of desiccation resistance with many life-history traits but a positive association with longevity in Drosophila melanogaster. The efficacy of stress as an environmental probe exposing such trade-offs follows from the high heritability of stress resistance in these experiments. Generalizations concerning evolutionary change come from the interaction between stress and its metabolic cost. At stressed species borders little available energy may remain beyond maintenance and survival needs so that extinctions become likely. In moderately stressed and narrowly fluctuating environments there should be sufficient genetic variability and metabolic energy to permit genetic adaptation. Phyletic gradualism is an expectation in these environments. In more stressed and widely fluctuating environments a punctuated evolutionary pattern is likely even though stasis may occur most of the time. An interpretation of evolutionary patterns therefore comes from an analysis of the interaction between stress (severity and variability), genetic variability, and energy availability, which can be summarized in an evolutionary templet.
自然种群会受到不同强度的非生物环境压力。一些生物体可以通过遗传降低代谢率来增强对压力的抵抗力。这种关系是果蝇抗干燥能力与许多生活史特征呈负相关，但与寿命呈正相关的基础。在这些实验中，压力作为揭示此类权衡的环境探针的有效性源于抗压力的高遗传性。关于进化变化的概括来自压力与其代谢成本之间的相互作用。在受压力的物种边界，除了维持生存所需之外，几乎没有可用能量剩余，因此灭绝很可能发生。在适度受压力且波动较小的环境中，应该有足够的遗传变异性和代谢能量来允许遗传适应。在这些环境中，渐进式进化是可以预期的。在压力更大且波动更广泛的环境中，即使大部分时间可能处于停滞状态，间断性进化模式也很可能出现。因此，对进化模式的一种解释来自于对压力（强度和变异性）、遗传变异性和能量可用性之间相互作用的分析，这可以总结在一个进化模板中。
