Dissertation Research: Comparative Analyses of Life History Evolution in Variable Environments: Cole's Paradox Revisited

研究人员正在研究一年生与多年生的习性，作为一组原产于美国西部干旱地区的相关植物在可变环境中持久性的替代策略。 他们将使用DNA序列数据来推断月见草属（柳叶菜科）Anogra组的祖先-后代关系。 他们将在这一关系假设的背景下测试一年一次的习惯与干旱的联系。 此外，他们将使用一年生物种和一种密切相关的多年生物种的人口统计学研究来测试预测有利于一年生与多年生习性的生存和繁殖模式。 大规模（系统发育）和小规模（人口统计）的比较研究相结合，将使研究人员能够检查进化变化的模式和驱动这种变化的具体机制。长期以来，人们一直认为，从多年生到一年生习性的转变是干旱地区多样化和适应的重要途径。 在这项关于驱动习惯变化的选择性力量的研究中，研究人员将进一步了解干旱土地生物多样性的驱动因素，以及植物在一般可变环境中持续存在的方式。

Venable0105145The researchers are studying the annual vs. perennial habit as alternative strategies for persistence in variable environments in a group of related plants native to the arid western United States. They will be using DNA sequence data to infer the ancestor-descendant relationships in the Section Anogra of the genus Oenothera (Onagraceae). They will test the association of the annual habit with aridity in the context of this hypothesis of relationships. In addition, they will use demographic studies of an annual species and a closely related perennial species to test for patterns of survival and fecundity predicted to favor the annual vs. perennial habit. The combination of large-scale (phylogenetic) and small-scale (demographic) comparative studies will allow the researchers to examine both the pattern of evolutionary change and specific mechanisms driving this change.It has long been suggested that the transition from the perennial to annual habit is an important pathway of diversification and adaptation in arid lands. In this study of the selective forces driving changes in habit, the researchers will further the understanding of the drivers of biotic diversity in arid lands, and the means by which plants persist in variable environments in general.