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

Richard L.博士Mayden和圣刘易斯大学的Nicholas J. Lang先生将研究Percusae家族的进化和生态学; Percusae是一种全北极淡水鱼类。该科由10个属和200多个物种组成，分布在北美和欧亚大陆。北美特有的部落Etheostomatini（4属，近200种）代表了该科中绝大多数物种的多样性。这组鱼类表现出许多典型的适应性辐射（非洲裂谷湖慈鲷，加拉帕戈斯雀）的特点，包括高多样性，强烈的两性异形，和一系列的生态专业化。最新的理论进展允许客观识别和表征自适应辐射。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家庭内进化关系的假设。这些关系将被用来确定和测试有关适应性辐射形成过程的假设。 该项目将培养一名博士生。此外，适应性辐射确实是现代进化生物学思想的基础。最近设计的方法使生物学家能够专注于那些表现出广泛适应性的生物群体，而不管包括多少物种。这使得研究的重点放在已经进化成新生态位的群体上，而不是那些在保留的祖先生态位内有许多物种的群体。镖鲈（Etheostomatine鱼类的通用名称）是一个多样化的群体，栖息在北美所有可能类型的淡水水体中的许多小生境中。有几个血统的镖鲈，其中每一个栖息在一个特征的微栖息地。虽然不同谱系的代表往往在当地动物群内的微生境隔离，但很少有密切相关的物种栖息在同一条河流中。多样化到新的生态位驱动早期镖进化的假设，而vicariance和/或当地的性选择的因素，潜在的高水平的物种多样性，将使用一个全面的系统发育树进行测试。这棵树将是有用的，许多未来的科学家感兴趣的进化和生态过程在这个有趣的群体。

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.