The Neoproterozoic Record of the Origin of Eukaryotes and Biogeochemical Change

化石记录中记载了生命的历史。由于全球层面的环境变化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，预测当前水平的变化对地球生物群的影响是可行的。要有效地解释这一记录，需要三种信息：(1)用于讨论化石的可靠的系统框架(即，基于系统发生关系的一组一致的、具有生物意义的名称和类别)；(2)可靠的地层位置(即，对化石在空间和时间上的出现进行排序的框架)；以及(3)环境变化的独立记录，允许将生物记录置于动态行星(岩石圈、大气层、水圈和生物圈)的背景下。尽管这样的数据通常可以用于过去5.4亿年期间沉积的化石，但目前还没有类似的框架来解释占生命历史约90%的较古老的化石。在这个项目中，PI建议提供详细的系统、地层和环境数据，以了解生活在现在之前9亿至5.4亿年前的有机体化石。这将几乎是详细研究地球生命史的时间段的两倍。更重要的是，很明显，审议期间是一个深刻的环境变化时期，对随后的进化过程产生了重大影响，从而影响了生命的多样性。得出的数据将有助于我们对地球环境和生物发展的关键时期的理解。这项研究还具有实用价值，因为建立可靠的地层和环境格架将有助于在含有未开发石油和矿床的岩石中进行资源勘探。

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.