Dissertation Research: Molecular Evolution, Adaptive Radiation, and Geographic Speciation in Banksia (Proteaceae)

9801572 Givnish这项研究试图对描述大陆适应性辐射的一个显著例子中的进化模式作出重要贡献。Banksia属（变形科）包括79种乔木、灌木和匍匐的木质垫，它们只存在于澳大利亚，并建立在广泛的气候和土壤中。有些特征在不同物种之间差异很大，例如叶子，可能从全叶到多刺，这些植物在开花植物中显示出最广泛的寿命范围。此外，在Banksia和相关的Dryandra属中，一些共生的物种对在叶和花的形态上显着趋同。基于叶绿体和核DNA的变异，将建立一棵班克兰及其相关属的系统树。一旦解决树将用于以下目的：1)分析我们的DNA数据和最近一组形态学数据之间的一致性，目的是基于这两种信息获得Banksia的分类；2)不同地理区域内和区域间物种形成历史的评价；3)将植物形态和生态的进化转变与推断的不同气候和/或基质的历史转变联系起来；4)确定共存的Banksia和Dryandra物种之间惊人的相似性是否代表在相似生态条件下的进化趋同或共享最近的共同祖先。这项拟议的研究将阐明澳大利亚最多样化和最具特色的植被群之一的历史、地理分布和生态。

9801572 Givnish This study seeks to make an important contribution toward describing the patterns of evolution in a striking example of continental adaptive radiation. The genus Banksia (Proteaceae) includes 79 species of trees, shrubs, and prostrate woody mats that occur only in Australia and are established in a broad range of climates and soils. Some characters vary greatly among the species, such as the leaves, which may vary from entire to spinose, and these plants display the widest range in lifespan known among flowering plants. In addition several co-occuring pairs of species in Banksia and the related genus Dryandra are remarkably convergent in leaf and flower form. A phylogeetic tree will be developed for Banksia and relatived genera based on variation in chloroplast and nuclear DNA. Once resolved the tree will be used for the following purposes: 1) analysis of the agreement between our DNA data and a recent set of morphological data with the aim of obtaining a classification of Banksia based on both kinds of information; 2) evaluation of the history of species formation within and between different geographic areas; 3) relating evolutionary shifts in plant form and ecology to inferred historical shifts to different climates and/or substrates; and 4) determination of whether the strikingly similarity between coexisting pairs of Banksia and Dryandra species represents evolutionary convergence under similar ecological conditions or the sharing of recent common ancestors. The proposed study will shed light on the history, geographic distribution, and ecology of one of the most diverse and characteristic groups of Australia's vegetation.