Comparative Study of Adaptive Radiation in Iguanian Lizards

9982736 Losos，Larson&Amp；de Queiroz生物学的一个中心目标是了解导致生物多样性的过程。特别令人感兴趣的是“适应性辐射”--一种情况，即一个祖先物种多样化，产生适应环境不同部分的各种后代。以前对适应性辐射的大多数研究都强调不同辐射的独特特征，而不是寻找共同的模式。由于这些研究在生物体类型、时间尺度、分析方法和所考虑的特征上都不同，因此这些研究的比较显示出更多的差异而不是相似之处或许并不令人惊讶。需要的是使用一致的方法对密切相关的生物体之间的适应性辐射进行比较研究，以检验适应性辐射普遍存在模式的假设。加勒比海不同岛屿上Anolis蜥蜴进化的规律表明，适应性辐射可能以类似的方式进化。其他种类的蜥蜴是否表现出类似的图案还不得而知。我们建议研究鬣蜥的独立辐射，以检验我们对加勒比海蜥蜴的研究提出的假设。我们在早期研究中开发的研究适应性进化和辐射的综合和多学科方法将扩展到大陆Anoles、澳大利亚Aagamides、Liolaemus和Scelopus。我们之所以关注鬣蜥，是因为它们在身体形态、行为和生态方面有着广泛的相似之处。每一个群体本身都是一个有价值的研究对象；此外，它们与加勒比海Anoles的密切进化关系使它们成为检验我们对加勒比海Anoles研究得出的适应性辐射假说的理想对象。对于每一类蜥蜴，我们将使用DNA数据得出进化树。利用这些树，我们将检验身体形态的进化变化与功能的进化变化相联系的假设，这反过来又会导致栖息地使用和行为的进化变化。为了验证这些假设，行为和生态的实地研究将得到形态和功能能力的实验室研究的补充。然后，我们将比较每个蜥蜴种群的进化多样化模式，看看是否存在相似之处，或者相反，是否每个种群都有自己独特的进化路径。

9982736Losos, Larson & deQueirozA central goal of biology is to understand processes responsible for biodiversity. Of particular interest are "adaptive radiations"-situations in which one ancestral species diversified to produce a variety of descendants adapted to use different parts of the environment. Most previous studies of adaptive radiation have emphasized unique features of different radiations rather than a search for common patterns. Because these studies differ in type of organism, time scale, method of analysis, and characters considered, it is perhaps not surprising that comparisons of these studies reveal more differences than similarities. What is needed is a comparative study of adaptive radiation among closely related organisms using consistent methodology to test the hypothesis that general patterns of adaptive radiation exist. Regular patterns in the evolution of Anolis lizards on different Caribbean islands suggest that adaptive radiations may evolve in similar ways. Whether other groups of lizards show similar patterns is unknown. We propose to study independent radiations of iguanian lizards to test hypotheses suggested by our studies of Caribbean anoles. The integrative and multidisciplinary approaches to the study of adaptive evolution and radiation developed in our earlier studies will be extended to mainland anoles, Australian agamids, Liolaemus, and Sceloporus. We focus on iguanian lizards because they share, at a broad level, similarities in body form, behavior, and ecology. Each group is a worthy subject in its own right; in addition, their close evolutionary relationship to Caribbean anoles makes them ideal for testing hypotheses about adaptive radiation derived from our studies of Caribbean anoles. For each lizard group, we will derive evolutionary trees using data from DNA. Using these trees, we will test the hypotheses that evolutionary change in body form is linked to evolutionary change in functional capabilities which, in turn, lead to evolutionary change in habitat use and behavior. To test these hypotheses, field studies of behavior and ecology will be complemented by laboratory studies of morphology and functional capabilities. We will then compare the pattern of evolutionary diversification in each lizard group to see if similarities exist or, conversely, whether each group has had its own unique evolutionary path.