Paleobiology of a Uniquely Well-Preserved Window on the Early Evolution of Multicellular Organisms

9805032Knoll 记录生命历史前 85% 的化石主要是微观的。 直到最近 5.44 亿年，大型动物的遗骸才出现，随后植物变得丰富，地质学家将这段时期命名为显生宙——可见生命的时代。 连接这些截然不同时代的关键事件是复杂多细胞生物的进化。 多细胞生物在动物、真菌和几类藻类中至少出现了六次。 一些化石表明，多细胞红藻、绿藻和原生藻菌（棕色和相关）藻类在十亿年前就已经存在。 多细胞性可能在微小的祖先动物中出现得相当早，但直到现在，古生物学家还认为任何前埃迪卡拉动物记录都无法获得。现在，一个非凡的化石沉积物为多细胞生物的早期多样化提供了前所未有的新线索。 中国 600-5.5 亿年前的陡山沱组磷岩含有三维保存的化石，记录了在前寒武纪岩石中发现的早期生命；事实上，它们必定属于任何时代最重要的化石矿床之一。提出了一项为期两年的研究项目，以研究陡山沱磷矿中多细胞化石的系统古生物学和古生物学。 研究小组将与北京大学张云教授合作，从我们之前的研究表明存在化石的地区收集大量材料。 新的、具有生产潜力的4地区也将在现场进行采样。 样品将在实验室制备并通过光学和电子显微镜进行研究。 预计这项研究将为理解生命史上的重大转变提供一个新的实证古生物学框架。

9805032KnollFossils that document the first 85 percent of the history of life are predominantly microscopic. Only in the last 544 million years have the remains of large animals and, later, plants become abundant, leading geologists to christen this interval the Phanerozoic Eon -- the age of visible life. The key event that connects these strikingly different eras is the evolution of complex multicellularity. Multicellular organisms arose at least six times in animals, fungi, and several groups of algae. A handful of fossils suggest that multicellular red, green, and stramenopile (brown and related) algae existed a billion years ago. Multicellularity may have arisen comparably early in tiny ancestral animals, but until now any pre-Ediacaran animal record was thought to be inaccessible to paleontologists.A remarkable fossil deposit is now shedding unprecedented new light on the early diversification of multicellular organisms. Phosphorites of the 600-550 million year old Doushantuo Formation, China, contain three-dimensionally preserved fossils that record of early life yet discovered in Precambrian rocks; indeed, they must rank among the most important fossil deposits of any age.A two-year research project is proposed to investigate the systematic paleontology and paleobiology of multicellular fossils in the Doushantuo phosphorites. In collaboration with Professor Zhang Yun of Beijing University, the research team will collect large volumes of material from localities that our previous research has shown to be fossiliferous. New, potentially productive4 localities will also be sampled in the field. Samples will be prepared in the laboratory and studied by light and electron microscopy. It is anticipated that this research will provide a new empirical, paleontological framework for understanding a major transition in the history of life.