Mechanisms of Constraint in the Evolutionary Radiation of a Crustacean Species Complex

由于它们共同的祖先，相关物种有许多相似之处，但也有重要的不同之处，因为每个物种都可能适应独特的环境。 物种之间的差异和相似性模式代表了“生物多样性的结构”。 该项目旨在了解这种结构如何随着时间的推移而发展的机械细节。 具体来说，PI将研究一组淡水甲壳类动物，片脚类动物，它们的共同祖先在大约800万年前入侵北美，并且已经多样化成今天存在的至少36种物种。 PI将使用DNA分析来重建物种多样化的历史模式，并使用统计方法来推断现存物种的特征是如何从其祖先中产生的。 该项目的第二个主要组成部分将是一个“选择实验”，在这个实验中，PI对端足类动物的实验种群施加进化压力，并监测物种性状在多代中的变化形式和速度。该项目意义重大，因为它提供了对生物多样性结构形成因素的深入了解。 虽然我们知道进化的过程是由物种的遗传组成、物种所经历的环境条件和其他因素所施加的一系列约束所塑造的，但我们目前对这些约束如何相互作用以产生我们在相关物种群体中观察到的结构没有足够的了解。 本项目采用补充方法来阐明这一过程。

Related species share many similarities due to their common ancestry, but also differ in important ways because each may be adapted to a unique environment. The patterns of differences and similarities among species represent the "structure of biological diversity". This project seeks to understand the mechanistic details of how this structure develops over time. Specifically, the PI will examine a group of freshwater crustaceans, amphipods, whose common ancestor invaded North America approximately 8 million years ago, and has since diversified into at least three-dozen species that exist today. The PI will use DNA analysis to reconstruct the historical pattern of diversification of the species, and use statistical methods to infer how the traits of extant species arose from their ancestors. A second major component of the project will be a "selection experiment" in which the PI imposes evolutionary pressures on experimental populations of amphipods and monitors the form and rate of change in the species' traits over many generations. This project is significant because it provides an in-depth understanding of the factors that give rise to structure in biological diversity. Although we know that the course of evolutionary change is shaped by sets of constraints imposed by the genetic makeup of species, the environmental conditions experienced by species, and other factors, we do not currently have an adequate understanding of how these constraints interact to produce the structure we observe within groups of related species. This project employs complementary methodological approaches to illuminate this process.