Evolutionary Analysis of the Generation and Loss of Biodiversity

吉莱斯皮 9726573 我们正在进行一项大型研究的一部分，研究物种生态和地理范围占领的动态性质。最终目标是确定进化史是否以及如何决定物种范围的大小，从而决定其灭绝的脆弱性。研究的重点是一种种类繁多的夏威夷群岛特有的辐射蜘蛛。目前的目标是：（1）解决4个系统之间的演化关系 蜘蛛的群体，其中两个广泛的岛屿内的差异，而其他主要是岛屿或山区之间的差异;和（2）对于一个单一的组，以产生有效的人口规模和基因流（使用分子标记）之间的估计每个物种的人口。 如果有可能通过物种的进化历史来确定物种之间分布的自然进化变化，那么就有可能区分自然分布的物种。 由于人类的影响，它们的范围受到限制。这项研究的目的是了解种群和物种之间的关系，以便我们能够继续测试是否可以预测一个物种的自然进化未来。我们已经论证过，对于以广泛迁徙为特征的物种，种群的局部细分是不可能的。因此，物种分化只有在种群变得孤立时才会发生，例如当它到达一个新的陆地时，新物种也可能在丰度和范围上扩大。在这种情况下，最近形成的物种群体的代表将是最广泛的，而该谱系中的老物种将更加有限，更容易灭绝。对于迁徙减少的物种，应该可以进行局部种群细分，细分物种在丰度和分布范围上变得更加有限。在第二种情况下，最近衍生的物种应该是最受限制和最容易自然灭绝的物种。在这项研究中产生的数据将表明，如何在进化枝之间的系统发育关系的信息可以最有效地与有效的数据相结合， 人口规模和人口之间的基因流动，以统计检验分布变化的重要模式。

Gillespie 9726573 We are undertaking part of a large study examining the dynamic nature of ecological and geographic range occupation by species. The ultimate goal is to determine whether, and how, evolutionary history dictates the size of a species range, and hence its vulnerability to extinction. The focus of the research is a large and diverse species radiation of spiders endemic to the Hawaiian Islands. The current objectives are: (1) to resolve the evolutionary relationships among 4 groups of the spiders, two of which differentiate extensively within islands, while the others differentiate primarily between islands or mountains; and (2) for a single group, to generate estimates of effective population size and gene flow (using molecular markers) between populations of each species. If it were possible to determine the natural evolutionary changes in distribution among species through their evolutionary history, then it may be possible to distinguish species that are naturally restricted in their range from those that have been confined due to human impact. The objective of the proposed study is to understand relationships among populations and species, so that we will be able to go on to test whether the natural evolutionary future of a species can be predicted. We have argued that, for species characterized by extensive migration, local subdivision of populations will be impossible. Therefore, species divergence can only occur when a population becomes isolated, for example when it reaches a new land mass, at which time the new species is also likely to expand in abundance and range. In such a scenario, the most recently formed representative of a species group will be the most widespread, while the older species in that lineage will be more restricted and vulnerable to extinction. For species exhibiting reduced migration, local population subdivision should be possible, with subdivided species becoming more restricted in abundance and range. In this second scenario the more recently derived species should be the most restricted and vulnerable to natural extinction. The data generated in this study will indicate how information on phylogenetic relationships among clades can be most effectively coupled with data on effective population size and gene flow between populations in order to statistically test for significant patterns of distributional change.