The Neoproterozoic Record of the Origin of Eukaryotes and Biogeochemical Change

生命的历史记录在化石中。由于全球环境变化的重大事件在地球历史上反复出现，因此通过研究这些重要事件前后的化石记录，预测当前变化水平对地球生物群的影响是可行的。要有效地解释这些记录，需要三种类型的信息：(1)用于讨论化石的健全的系统框架（即基于系统发育关系的一套一致且具有生物学意义的名称和类别）；(2)可靠的地层位置（即对化石产状在空间和时间上排序的框架）；(3)环境变化的独立记录，允许在动态行星（岩石圈、大气、水圈和生物圈）的背景下放置生物记录。虽然对于过去5.4亿年间沉积的化石，这些数据通常是可用的，但目前还没有一个可比较的框架来解释更古老的化石，这些化石约占生命历史的90%。在这个项目中，PI计划为生活在距今9亿至5.4亿年前的生物化石提供详细的系统、地层和环境数据。这将使地球生命史的详细研究时间几乎延长一倍。更重要的是，很明显，所考虑的时间间隔是一个深刻的环境变化的时期，这种变化对后来的进化过程产生了重大影响，从而对生命的多样性产生了重大影响。导出的数据将有助于改进我们对地球环境和生物发展的关键时期的理解。研究还具有实用价值，建立可靠的地层和环境格架将有助于对含未开发油气矿床的岩石进行资源勘探。

The history of life is recorded in the fossil record. Because significant episodes of global-level environmental change have recurred in the earth's history, it is feasible to predict the effect of current levels of change on the earth's biota, by studying the fossil record before and after those important episodes. Three types of information are necessary to interpret this record effectively: (1) a sound systematic framework (that is, a consistent and biologically meaningful set of names and categories that are based on phylogenetic relationships) for discussing the fossils; (2) reliable stratigraphic placement (that is, a framework for ordering fossil occurrences in space and time); and (3) an independent record of environmental change that allows placement of the biological record in the context of a dynamic planet (lithosphere, atmosphere, hydrosphere, and biosphere). Although such data are routinely available for fossils deposited during the past 540 million years, there is at present no comparable framework for interpreting older fossils, which constitute about 90% of life's history. In this project, the PI proposes to provide detailed systematic, stratigraphic, and environmental data for the fossils of organisms that lived 900-540 million years before the present. This will almost double the period for which the life history of the planet can be studied in detail. More importantly, it is clear that the interval under consideration was a time of profound environmental change that had a major influence on the subsequent course of evolution and, hence, the diversity of life. The derived data will help refine our understanding of a critical period in the Earth's environmental and biological development. The research is also of practical value in that the establishment of a reliable stratigraphic and environmental framework will facilitate resource exploration in rocks containing under exploited petroleum and ore deposits.