CAREER: Identifying controls on size evolution through comparative analysis

在生物学中，尺寸和功能是不可分割的，因为各种各样的生理和生活史特征都与尺寸有关。因此，大小演化模式可以补充分类多样性和地球化学代理数据，为生态相互作用和环境变化对生命史上重大事件的影响提供定量限制，从真核生物的起源到寒武纪大爆发，海洋动物的早期古生代辐射，新生代哺乳动物的兴起，大规模灭绝和随后恢复的情况，对气候变化的反应，抽样偏差对分类多样性的潜在影响。在大小进化研究中，最有趣的观察之一是，在分类学辐射、大灭绝和全球环境变化的间隔期间，变化的模式经常在远亲分类群之间共享。就像全面的全球地层范围汇编使我们对生物多样性动态的理解取得了巨大进展一样，跨越显生期的类似身体尺寸汇编对于确定这一关键功能特征的进化控制至关重要。这项研究的目的是确定进化动力学是否以及何时在显生宙的主要分支中共享，从而确定影响生物大小进化的因素。为了实现这一目标，PI将为有孔虫、腕足动物和腹足动物编制全面的、属级大小的数据集。这些群体占海洋化石记录中属多样性的25%以上，但在基本解剖学、生理学和生态学方面存在差异。通过确定每个分支中尺寸进化的最佳模型，确定尺寸进化模式在显生宙期间是否发生了变化，并测试进化动力学是否在这些群体中共享，PI将确定是否存在普遍的生态或环境控制尺寸进化，或者相反，作为生态和生理特性的函数，不同种群之间的大小演化动态不同，或者作为生物或环境环境的函数，随着地质时间的变化而变化。这项研究将为PI的长期教育和推广计划提供基础。参与身体尺寸数据的收集和分析需要相对较少的技术培训或使用昂贵的仪器或设施。因此，它提供了一个理想的机会，让各级学生直接参与数据收集和分析，无论是在课堂上，还是作为暑期密集研究项目的一部分。每年夏天，六名高中生和一名高中教师将协助本科生和研究生进行数据收集和初步分析。这位高中教师将在Yerba Buena高中的学年期间继续收集和分析数据，这所学校为大多数经济弱势家庭和STEM领域代表性不足的群体提供服务。研究生将每两周访问一次班级，监督数据收集和分析，班级将在每年春天访问斯坦福大学，作为一次顶点体验。PI将根据该项目的数据开发一门新的大一研讨课。项目成功与否将通过调查来评估学生参与项目前后对STEM领域和未来计划的态度，以及对学生未来几年教育历史的长期跟踪。从该项目收集的数据将作为独立的数据集在Dryad存档，但也将输入古生物学数据库，这是一个开放获取的、社区范围内的化石发生数据汇编。尺寸数据对于进化动力学分析和化石记录的保真度是不可或缺的。由于这项研究产生的数据将涵盖已知海洋属的很大一部分，因此它们很可能被社区广泛用于与拟议项目无关的研究中。

CAREER: Identifying controls on size evolution through comparative analysisJonathan L. Payne, Department of Geological and Environmental Sciences, Stanford UniversityEAR-1151022ABSTRACTSize and function are inseparable in biology because a wide variety of physiological and life-history traits scale with size. Patterns of size evolution can therefore complement taxonomic diversity and geochemical proxy data by providing quantitative constraints on the influence of ecological interactions and environmental change on major events in the history of life, from the origin of eukaryotes to the Cambrian explosion, the early Paleozoic radiation of marine animals, the Cenozoic rise of mammals, the circumstances of mass extinctions and subsequent recoveries, responses to climate change, and potential influences of sampling bias on taxonomic diversity. One of the most intriguing observations in the study of size evolution is that patterns of change are often shared across distantly related taxa during intervals of taxonomic radiation, mass extinction, and global environmental change. Just as comprehensive, global compilation of stratigraphic ranges has enabled vast advances in our understanding of biodiversity dynamics, an analogous compilation of body sizes spanning the Phanerozic is critical for identifying controls on the evolution of this key functional trait. The goal of this study is to determine if and when evolutionary dynamics have been shared across major clades through the Phanerozoic and thereby identify the factors that shape the evolution of organism size. To accomplish this goal, PI will compile comprehensive, genus-level size datasets for foraminifera, brachiopods, and gastropods. These groups comprise more than 25% of the genus diversity in the marine fossil record but differ in basic anatomy, physiology, and ecology. By identifying the best model for size evolution within each clade, determining whether or not the mode of size evolution has shifted during the Phanerozoic, and testing whether evolutionary dynamics are shared across these groups, PI will determine whether there are universal ecological or environmental controls on size evolution or if, instead, the dynamics of size evolution vary among groups as a function of ecological and physiological properties or change through geological time as a function of biological or environmental circumstances.This study will provide the foundation for PI's long-term education and outreach program. Participation in the collection and analysis of body size data requires relatively little technical training or access to expensive instruments or facilities. Consequently, it offers an ideal opportunity to involve students at all levels directly in data collection and analysis, both in the classroom and as part of intensive summer research programs. Each summer, six high school students and one high school teacher will assist undergraduates and the graduate student in data collection and preliminary analyses. The high school teacher will continue data collection and analysis during the academic year at Yerba Buena High School, a school that serves a majority population of economically disadvantaged families and underrepresented groups in STEM fields. The graduate student will visit the class on a biweekly basis to supervise data collection and analysis, and the class will visit Stanford each spring as a capstone experience. The PI will develop a new freshman seminar class with exercises based on data from this project. Project success will be evaluated using surveys to assess student attitudes toward STEM fields and future plans before and after participation in the project, as well as long-term tracking of students' educational histories in future years.Data collected from this project will be archived as stand-alone datasets at Dryad, but will also be entered into the Paleobiology Database, an open-access, community-wide compilation of fossil occurrence data. Size data are integral to analyses of evolutionary dynamics and the fidelity of the fossil record. Because the data produced in this study will cover a significant fraction of known marine genera, they are likely to be used broadly by the community in studies unrelated to the proposed project.