Collaborative Research: The Causes and Consequences of Trade-offs in Model Populations

生物已经发展出许多抵抗捕食者和病原体的机制。这些机制通常被认为会给生物带来“代价”，例如，在没有捕食者的情况下，抵抗捕食者的生物（相对于敏感的生物）是劣等的竞争者。然而，在大多数实验系统中，这种权衡的原因和后果已被证明难以检验。大肠杆菌及其病毒捕食者（噬菌体）是研究这种权衡的理想模式生物，因为它们易于繁殖，生长迅速，而且关于它们的生物学有大量的背景文献。将进行实验，直接检查大肠杆菌竞争能力和噬菌体抗性之间权衡的遗传和生理原因，以及在特定环境条件下，这种权衡在短期（生态）和长期（进化）时间尺度上对种群和群落的影响。抗性和竞争能力之间存在权衡的前提构成了许多关于生物多样性起源和捕食者或病原体与其猎物相互作用的假设的基础。了解这种权衡将在纯科学和应用科学中具有广泛的价值，包括提高气候变化对生物多样性影响的预测准确性，外来物种引入的影响，以及人类病原体的毒力进化。

Organisms have developed numerous mechanisms for resisting predators and pathogens. These mechanisms are generally thought to incur a "cost" to the organism, such that predator resistant organisms are inferior competitors (relative to sensitive organisms) in the absence of predators. However, the causes and consequences of this tradeoff have proven difficult to examine in most experimental systems. Escherichia coli and its viral predators (bacteriophage) are ideal model organisms with which to study this tradeoff, because they are easy to propagate, they grow rapidly and because there is an abundance of background literature on their biology. Experiments will be performed that directly examine the genetic and physiological causes of the tradeoff between competitive ability and bacteriophage resistance in E.coli, and the effects of this tradeoff on populations and communities over short (ecological) and long (evolutionary) time scales under specific environmental conditions.The premise that there is a tradeoff between resistance and competitive ability forms the basis for numerous hypotheses on the origin of biodiversity and the interaction of predators or pathogens and their prey. Understanding this tradeoff will have widespread value in both pure and applied sciences, including increasing the accuracy of predictions of climate change effects on biodiversity, the impact of foreign species introduction, and the evolution of virulence in human pathogens.