Evolution of thermal tolerance in multifarious environments

Species extinction rates are many times greater than the direst predictions made two decades ago by environmentalists, largely because of human impact. Major concerns are associated with the predicted higher recurrence and severity of extreme events, such as heat waves. Although tolerance to these extreme events is instrumental to species survival, little is known whether and how it evolves in natural populations, and to what extent it is affected by other environmental stressors. Here, we study physiological and molecular mechanisms of thermal tolerance over evolutionary times in multifarious environments. Using the practice of ‘resurrection ecology’ on the keystone grazer Daphnia magna, we quantified genetic and plastic differences in physiological and molecular traits linked to thermal tolerance in historical and modern genotypes of the same population. This population experienced an increase in average temperature and occurrence of heat waves, in addition to dramatic changes in wate...

物种灭绝速率较二十年前环保人士做出的最严峻预测高出数倍，其主要成因是人类活动的影响。当前最受关注的问题之一，是极端事件（如热浪）的发生频率与严重程度预计将进一步升高。尽管对这类极端事件的耐受能力对物种存续至关重要，但目前我们对自然种群中该耐受能力是否会演化、如何演化，以及其受其他环境胁迫因子影响的程度均知之甚少。本研究聚焦多样环境下热耐受的生理与分子机制，开展演化时间尺度上的探究。本研究以关键牧食类群大型溞（Daphnia magna）为研究对象，采用复活生态学（resurrection ecology）方法，对同一种群历史与现代基因型中与热耐受相关的生理及分子性状的遗传差异与表型可塑性差异进行了定量分析。该种群不仅经历了平均气温升高与热浪频发的变化，同时还遭遇了水体环境的剧烈改变（原文未完整呈现）。