Complexity in the oldest animal ecosystems

埃迪卡拉纪（635-541 Ma）是复杂生命进化的一个基本阶段。这次的典型代表是埃迪卡拉生物群，一个全球分布的大型、软体、形态复杂的多细胞生物群，其生物亲和性受到强烈质疑。我的研究将数据驱动的模型、先进的仪器、实验程序和实地工作结合到一个单一的研究项目中，针对三个基本问题：1)保存在多大程度上偏向于早期生命的化石记录？2)埃迪卡拉动物群是如何发挥基本生物学功能的？3)最古老的动物生态系统有多复杂？******在评估化石记录的保真度时，必须考虑保存偏差。我的研究小组应用多学科实验室为基础的调查，通过设计腐烂室，连续监测和报告的地质，生物和化学产物的衰变（pH值，CO2, H2S, CH4， NO2等），除了沉积物/液体/气体提取工具，允许采样与最小的破坏。通过这种方法，我们能够确定异常石化的速度和模式的关键阶段，并为早期生命化石记录的保真度设定现实的限制。******为了解决埃迪卡拉生物群的生物学功能，我将系统发育研究与功能形态学结合起来。我的研究小组率先使用了埃迪卡拉生物在虚拟海洋条件下的数字重建来展示替代的喂养策略，甚至提出了缺乏化石附属物的形式的流动性。我的研究目标是单个物种如何在生态系统中相互作用，从而对埃迪卡拉生态系统中隐藏的复杂性进行评估。******由于生态系统的复杂性可以通过多种方式进行研究，我的实验室开发了创新的模糊生态空间建模方法，针对生态系统中生物所占据的战略位置的进化、扩展甚至丧失（即生态位）。考虑到它们的古老，埃迪卡拉纪的生态系统通常被解释为相对简单。然而，根据我的研究，古生态学研究表明：1)许多埃迪卡拉生物群之间竞争相互作用导致物种形成的可能性；2)最古老的埃迪卡拉生物群扩大了繁殖策略；3)随着穿透式挖洞和捕食的出现，最新埃迪卡拉生物群扩大了营养结构；4)移动埃迪卡拉生物群的多样性比之前假设的要大。在纳米比亚和伊朗进行的有针对性的实地项目将提供必要的数据，以评估从埃迪卡拉纪到寒武纪，生态位的创造、占领和破坏是如何变化的。最终，我的研究将是评估动物生命初期生物相互作用和周转规模的核心

The Ediacaran Period (635-541 Ma) captures a fundamental stage in the evolution of complex life. Typifying this time are the Ediacara biota, a globally distributed group of large, soft-bodied, morphologically complex multicellular organisms whose biological affinities are strongly contested. My research combines data-driven modeling and advanced instrumentation with experimental procedures and field work into a single research program targeting three fundamental questions: 1) to what extent is preservation biasing the fossil record of early life? 2) How did the Ediacara biota perform basic biological functions? And 3) how complex were the oldest animal ecosystems?******Preservational biases must be considered when evaluating the fidelity of the fossil record. My research group applies multidisciplinary laboratory-based investigations into soft-tissue fossilization by designing decay chambers that continuously monitor and report the geological, biological, and chemical products of decay (pH, CO2, H2S, CH4, NO2, etc.), in addition to sediment/liquid/gas extraction tools that allow for sampling with minimal disruption. Through this approach, we are able to identify key stages in the tempo and mode of exceptional fossilization, and set realistic limits on the fidelity of the fossil record of early life. ******In order to address the biological functions of the Ediacara biota, I combine phylogenetic studies with functional morphology. My research group has pioneered the use of digital reconstructions of Ediacaran organisms subjected to virtual oceanic conditions to demonstrate alternative feeding strategies and even propose mobility in forms that lack fossilized appendages. My approaches target how individual species interacted within an ecosystem, leading to evaluations of the hidden complexity within Ediacaran ecosystems. ******As ecosystem complexity can be investigated in many ways, my laboratory has developed innovative fuzzy ecospace modelling approaches that target the evolution, expansion, and even loss of strategic positions occupied by organisms within an ecosystem (i.e. niche). Given their antiquity, Ediacaran ecosystems are typically interpreted as relatively simple. However, paleoecological studies stemming from my research have demonstrated 1) the likelihood of competitive interactions between many Ediacara biota leading to speciation, 2) expanded reproductive strategies among the oldest Ediacara biota, 3) expanded trophic structure in the latest Ediacaran with the advent of penetrative burrowing and predation, and 4) a greater diversity of mobile Ediacara biota than previously hypothesized. Targeted field programs in Namibia and Iran will provide the data necessary to evaluate how niche creation, occupation, and destruction has changed throughout the Ediacaran and into the Cambrian. Ultimately, my research will be central to evaluating the magnitude of biotic interactions and turnover at the dawn of animal life.**