Dynamical Change in Global Biogeochemical Cycles Accompanying Early Animal Evolution

0420592罗斯曼该项目旨在确定和量化早期动物生命进化影响全球地球化学循环变化的方式，并受其影响。有趣的时间间隔大约在5亿至6亿年前;它始于已知最早的微观动物化石，并以海洋动物的快速多样化而告终，称为“寒武纪大爆发”。“最近基于地球化学数据分析的工作表明，这些演变变化伴随着全球碳循环的重大动态转变。这种转变应该伴随着海洋氧化作用的增加。由于演化创新本身应该受到氧气浓度增加的支持，寒武纪大爆发可能既是全球地球化学循环变化的原因，也是其结果。本项目将结合地球化学理论、地质野外研究、有机地球化学和演化生物学的努力来验证这些假设的有效性。全球碳循环的一种新的理论公式提供了一种将碳循环的变化与可以从古代沉积物中提取的特定有机化合物的同位素组成变化联系起来的方法。通过分析地球化学数据推断出的地球化学循环的变化将与动物化石记录以及藻类和其他原生生物微化石的进化有关。这一主题是进化理论和地球历史的核心。这项工作旨在说明，在生命历史上最重要的间隔之一，环境变化如何以及为什么与生物圈的变化相互作用。它将向我们展示全球地球化学循环与它们所支持的生物圈的特定方面的关系，该项目还包括努力改善进化、地球历史和地球化学循环方面的教育，重点是它们的共同作用。两个博物馆的展览将有助于教育公众。该项目的跨学科性质也将为研究生的教育提供独特的机会。

0420592RothmanThis project seeks to identify and quantify the ways in which the evolution of early animal life influenced, and was influenced by, changes in global biogeochemical cycles. The time interval of interest ranges roughly from 500-600 million years ago; it began with the earliest known microscopic animal fossils and culminated with the rapid diversification of marine animals known as the "Cambrian explosion." Recent work based on analyses of geochemical data indicates that these evolutionary changes were accompanied by a major dynamical transition in the global carbon cycle. This transition should have been accompanied by increased oxygenation of the oceans. Because the evolutionary innovations themselves should have been favored by increased oxygen concentrations, the Cambrian explosion may have been both a cause and an effect of changes in global biogeochemical cycles.This project will test the validity of these hypotheses by combining efforts in biogeochemical theory, geologic field studies, organic geochemistry, and evolutionary biology. A new theoretical formulation of the global carbon cycle provides a means of relating changes in the carbon cycle to changes in the isotopic compositions of specific organic compounds that can be extracted from ancient sediments. Changes in biogeochemical cycling inferred from analysis of the geochemical data will then be related to the fossil record of animals and the evolution of algal and other protistan microfossils.The subject is central to both evolutionary theory and Earth history. The work seeks to specify, for one of the most important intervals in the history of life, how and why environmental change interacted with changes in the biosphere. It promises to show us the extent to which global biogeochemical cycles are related to specific aspects of the biosphere they support.The project also includes efforts to improve education in evolution, Earth history, and biogeochemical cycles, with emphasis on their joint interaction. Exhibits at two museums will contribute to the education of the general public. The interdisciplinary nature of the project will also offer unique opportunities for the education of graduate students.