Historical Biogeography of Symplocos, an Amphi-Pacific Tropical Disjunct Plant

Fritsch和almeda0126631博士。加州科学院的Peter Fritsch和Frank Almeda和他们的同事正在用DNA序列数据研究热带开花植物Symplocos属的系统发育关系，以测试关于“两太平洋热带”分布的生物体进化的相互竞争的假设。这些植物群今天主要或只生长在美洲的热带地区和西太平洋沿岸的陆地上。这些陆地生物是如何占据今天被数千英里的海洋隔开的地区的，人们还不太清楚。一种解释这种模式的假说认为，早第三纪，在白令海峡和北大西洋高纬度地区周围，连接北美和欧亚大陆的陆桥上的一个或两个陆桥上的洲际分散。另一个与之竞争的假说认为，这些植物扩散的主要途径发生在晚白垩纪/早第三纪的泛热带地区，当时大西洋比现在窄得多。研究人员将分析来自Symplocos样本的DNA序列数据，以估计物种关系的模式和主要亚群的洲际分裂时间。这些数据将在Symplocos广泛的化石记录的背景下进行解释，从而得出该群体生物地理历史的综合观点。该项目将把实验室工作与从拉丁美洲和东南亚几个国家实地采集样本结合起来。该项目的广泛科学意义和社会影响将有利于环境保护和科学教育。通过促进对过去热带植被运动的推断，从该项目中获得的知识将有助于解决目前正在发生的气候变化的生态影响的更广泛问题。此外，它将有助于发展和完善热带国家的保护战略，因为许多Symplocos物种是稀有和濒危的。该项目将支持和培养下一代生物生物学家，包括本科生、硕士和博士生参与原创研究项目。由于拟议的研究将在一个主要的大都会自然历史博物馆进行，因此存在大量的机会向公众展示这项研究的结果及其影响。这将采取在流行期刊上发表文章的形式，在博物馆的公共场所展出，成人教育课程，以及为游客举办讲座。

Fritsch and Almeda0126631Drs. Peter Fritsch and Frank Almeda at the California Academy of Sciences and their colleagues are studying the phylogenetic relationships of the tropical flowering plant genus Symplocos with DNA sequence data to test competing hypotheses on the evolution of organisms with "amphi-Pacific tropical" distributions. These are groups of plants that occur today primarily or exclusively in the tropical areas of the Americas and the lands bordering the western Pacific Rim. The means by which these land organisms have come to occupy areas that are today separated by thousands of miles of Ocean are not well understood. One hypothesis explaining this pattern proposes intercontinental dispersion across one or both of the land bridges connecting North America and Eurasia in the Early Tertiary around the high-latitude regions of Beringia and the North Atlantic. A competing hypothesis maintains that the primary avenue for the dispersion of these plants occurred pan-tropically in the Late Cretaceous/Early Tertiary, when the Atlantic Ocean was much narrower than today. The investigators will analyze DNA sequence data from Symplocos samples to estimate both the pattern of species relationships and intercontinental splitting times of major subgroups. These data will in turn be interpreted in the context of the extensive fossil record of Symplocos to arrive at a synthetic view of the biogeographical history of this group. The project will integrate laboratory work with field collection of samples from several countries, in Latin America and S.E. Asia.The broader scientific significance and societal ramifications of this project will benefit both environmental protection and science education. By facilitating inferences about the past movements of tropical vegetation, the knowledge derived from this project will contribute to the broader issues of the ecological effects of climate changes that are occurring at present. Further, it will help develop and refine conservation strategies of tropical countries, as many Symplocos species are rare and endangered. The project will contribute to the support and training of the next generation of organismal biologists by including undergraduate, Masters, and Ph.D. students involved in original research projects. Because the proposed research will be conducted at a major metropolitan natural history museum, ample opportunities exist to present the results of this research and its implications to the general public. This will take the form of articles in popular periodicals, displays in the museum's public venues, adult education courses, and lectures for visitors.