Dissertation Research: Phenotypic Plasticity of Jaw and Skull Morphology in the Cichlid Fishes, Geophagus braziliensis and G. steindachneri

表型可塑性是生物体的某些特征对环境变化的反应。这种可塑性通常有遗传基础，因此会影响进化的速度和方向。在脊椎动物中，形态可塑性鲜为人知。越来越多的证据表明，巴西盾叶蝉和斯廷达克纳里叶蝉代表了叶蝉的极端发育模式。我们的研究旨在回答以下问题：(1)开始摄食的大小对所表达的形态可塑性有什么影响？(2)可诱导的可塑性是否存在年龄相关的差异？(3)诱导的形态差异是否会影响与不同摄食方式相关的饲料的摄食效率？(4)颌骨和头骨的可塑性是否存在遗传差异？这项研究将超越对形态可塑性的描述；它将在发育、遗传、功能和生态背景下考察可塑性。只有通过这种跨学科的方法，才能理解可塑性对进化的影响，以及可塑性本身的进化。8700940麦考姆表型可塑性是生物体的某些特征对环境变化的反应。这种可塑性通常有遗传基础，因此会影响进化的速度和方向。在脊椎动物中，形态可塑性鲜为人知。越来越多的证据表明，巴西地鼠(Geopagus Brazilisis)和斯氏刺鱼(G.steindachneri)的颌骨和头骨形态代表了叶鱼的极端发育模式。我们的研究旨在回答以下问题：(1)开始摄食的大小对所表达的形态可塑性有什么影响？(2)可诱导的可塑性是否存在年龄相关的差异？(3)诱导的形态差异是否会影响与不同摄食方式相关的饲料的摄食效率？(4)颌骨和头骨的可塑性是否存在遗传差异？这项研究将超越对形态可塑性的描述；它将在发育、遗传、功能和生态背景下考察可塑性。只有通过这种跨学科的方法，才能理解可塑性对进化的影响，以及可塑性本身的进化。8700999约翰逊发声行为在鸣禽的进化过程中很重要，但很少有研究试图根据发声信息来解释形态和遗传多样性。这项研究将整合高度多型性的北美红嘴鸟(Loxia Curvirostra)复合体的发声、形态和遗传数据。这一群体呈现了一个尚未解决的进化悖论：这种鸟类是游牧的，这意味着基因流动的速度很高，但该群体内的喙大小、身体大小和羽毛颜色都存在极大的多样性。关于自然界的几个可测试的替代假说

Phenotypic plasticity is the modification of some trait of an organism in response to environmental change. Often this plasticity has a genetic basis and as a result can influence the rate and direction of evolution. Morphological plasticity is little known among vertebrates. Increasing evidence indicates braziliensis and G.steindachneri, which represent the extremes of cichlid developmental modes. Our research aims to answer the following questions: (1) What effect does the size at which feeding commences have on the amount of morphological plasticity that is expressed? (2) Are there age-related differences in the amount of plasticity that can be induced? (3) Do induced morphological differences affect feeding efficiency on diets that are associated with different feeding modes? (4) Is there genetic variation for the plasticity of jaw and skull bones? This study will go beyond a description of morphological plasticity; it will examine plasticity in a developmental, genetic, functional, and ecological context. Only through such an interdisciplinary approach can the effect of plasticity on evolution, and the evolution of plasticity, itself, be understood. 8700940 McCume Phenotypic plasticity is the modification of some trait of an organism in response to environmental change. Often this plasticity has a genetic basis and as a result can influence the rate and direction of evolution. Morphological plasticity is little known among vertebrates. Increasing evidence indicates that jaw and skull morphology of cichlid fishes, Geophagus braziliensis and G.steindachneri, which represent the extremes of cichlid developmental modes. Our research aims to answer the following questions: (1) What effect does the size at which feeding commences have on the amount of morphological plasticity that is expressed? (2) Are there age-related differences in the amount of plasticity that can be induced? (3) Do induced morphological differences affect feeding efficiency on diets that are associated with different feeding modes? (4) Is there genetic variation for the plasticity of jaw and skull bones? This study will go beyond a description of morphological plasticity; it will examine plasticity in a developmental, genetic, functional, and ecological context. Only through such an interdisciplinary approach can the effect of plasticity on evolution, and the evolution of plasticity, itself, be understood. 8700999 Johnson Vocal behavior is important in evolutionary processes in songbirds, yet few studies have attempted to explain morphological and genetic diversification in light of vocal information. This research will integrate vocal, morphological, and genetic data in the highly polytypic North American red crossbill (Loxia curvirostra) complex. This group presents an unsolved evolutionary paradox: the birds are nomadic, suggesting a high rate of gene flow, yet there is extreme diversity in bill size, body size, and plumage coloration within the group. Several testable alternative hypotheses regarding the nature