DISSERTATION RESEARCH: Theories of Adaptive Radiations: A Test Using the Family Percidae (Teleostei: Perciformes)

圣路易斯大学的理查德·L·梅登博士和尼古拉斯·J·朗先生将研究珀西达科的进化和生态，这是一种全北极淡水鱼。该科由10个属和200多种组成，分布在北美和欧亚大陆。北美特有部落Etheostomatini(4属近200种)代表了该科绝大多数物种水平的多样性。这类鱼表现出许多典型适应性辐射(非洲裂谷湖慈尾鱼、加拉帕戈斯雀类)的特征，包括高度多样性、强烈的性别二态和一系列生态专门化。最近的理论进展使自适应辐射的客观识别和表征成为可能。为了在Percids中实施这些测试，获奖者将使用核和线粒体DNA序列以及形态和行为特征构建一个关于家族内部进化关系的假说。这些关系将被用来确定和检验关于自适应辐射形成过程的假设。该项目将培养一名博士生。此外，从字面上讲，适应性辐射是关于进化生物学的现代思想的基础。最近设计的方法使生物学家能够专注于那些显示出广泛适应能力的有机体群体，无论包括多少物种。这使得研究重点放在那些已经进化成新的生态位的群体，而不是那些在保留的祖先生态位中有许多物种的群体。达特鱼(Etheostomatine鱼类的俗称)是一个多样化的群体，生活在北美所有可能类型的淡水水体中的许多生态位中。飞镖有几个谱系，每一个都生活在一个独特的微生境中。虽然不同谱系的代表经常根据当地动物体内的微生境进行隔离，但关系密切的物种很少居住在同一条溪流中。我们将使用一个全面的系统发育树来检验这一假设，即多样化进入新的生态位推动了更早期的飞镖进化，而替代和/或局部性别选择是导致高水平物种多样性的因素。这棵树将对这个有趣的群体中对进化和生态过程感兴趣的许多未来科学家有用。

Dr. Richard L. Mayden and Mr. Nicholas J. Lang of Saint Louis University will study the evolution and ecology of the family Percidae; a Holarctic group of freshwater fishes. The family is comprised of 10 genera and over 200 species distributed across North America and Eurasia. The North American endemic tribe Etheostomatini (4 genera and nearly 200 species) represents the vast majority of species-level diversity within the family. This group of fishes exhibits many characteristics of the classic adaptive radiations (African rift lake cichlids, Galapagos finches) including high diversity, strong sexual dimorphism, and a range of ecological specializations. Recent theoretical advances have allowed for the objective identification and characterization of adaptive radiations. In order to implement these tests within the percids, the awardees will construct a hypothesis of evolutionary relationships within the family using nuclear and mitochondrial DNA sequences, as well as morphological and behavioral characters. These relationships will be used to identify and test hypotheses about the processes through which adaptive radiations form. This project will train a doctoral student. In addition, adaptive radiations are, quite literally, the foundation for modern ideas about evolutionary biology. Recently devised methods have allowed biologists to focus on those groups of organisms that display a wide range of adaptations regardless of how many species are included. This has focused research on groups that have evolved into new niches instead of those that have many species within a retained ancestral niche. Darters (the common name for Etheostomatine fishes) are a diverse group that inhabits many niches in all possible types of freshwater bodies in North America. There are several lineages of darters, each of which inhabits a characteristic microhabitat. While representatives of divergent lineages often segregate by microhabitat within a local fauna, it is rare for closely related species to inhabit the same stream. The hypothesis that diversification into new niches drove early darter evolution, while vicariance and/or local sexual selection are the factors underlying high levels of species diversity, will be tested using a comprehensive phylogenetic tree. This tree will be useful to many future scientists interested in both evolutionary and ecological processes within this interesting group.