EAPSI: Determining the Biology and Ecology of One of Earth's Earliest animals: Dickinsonia

埃迪卡拉生物群的化石是地球上宏观的多细胞生物的最早证据。这种多样化的软体生物群有助于弥合在地球早期大部分历史上已知存在的微观、单细胞生命形式与今天存在的复杂、熟悉的形式之间的进化鸿沟。Dickinsonia是这一生物群中一个常见而多样的成员，但人们对它的了解仍然很少。确定这种早期有机体的生态学和生物学将为我们理解早期生命的进化提供重要的见解。在南澳大利亚州的弗林德斯山脉地区发现了丰富的化石，包括数百个狄金索尼亚化石，其中许多保存在南澳大利亚博物馆(SAM)。前往南澳大利亚州将允许访问这一无与伦比的数据集，并允许与该地区标本的主要专家Jim Gehling博士合作。将对南澳大利亚州埃迪卡拉纪沉积物中的Dickinsania进行研究，以检验两个假设：1)以前确定的物种差异可以通过形态差异来识别，而不是各种保存模式的人工产物；2)Dickinsania具有更好的环境栖息地，是Ediacara生物群中最丰富的生物之一。数据还将被用来解决大小、频率和空间模式可以在多大程度上向我们提供关于这种独特有机体的自生体和共生体的信息。这些假说将通过四个目标进行检验：1)确定形态的可变性，以研究物种形成；2)使用整个床面的照片以及关于狄金松的存在、不存在和丰富的详细报告来确定优势度和环境偏好；3)对尺寸和丰度数据的床面规模观察也将被记录下来，以及狄金森和其他分类学群体之间的空间关系，以检查这种古老生物的生态重要性；以及4)评估这一化石记录中潜在的保存偏见。该NSF EAPSI奖是与澳大利亚科学院合作资助的。

Fossils of the Ediacara biota, represent the earliest evidence of macroscopic, multicellular organisms on Earth. This diverse fauna of soft-bodied organisms helps to bridge the evolutionary gap between microscopic, unicellular life forms known to exist through most of Earth's early history and the complex, familiar forms that exists today. Dickinsonia is a common and diverse member of this biota, however it remains poorly understood. Determining the ecology and biology of this early organism will provide critical insight to our understanding of the evolution of early life. Abundant fossils, including hundreds of Dickinsonia have been identified in the Flinders Ranges area of South Australia and many are housed in the South Australia Museum (SAM). Travel to South Australia will allow access to this unparalleled data set and permit collaboration with Dr. Jim Gehling (at the SAM), the premier expert on specimens from this region.Study of Dickinsonia from the Ediacaran deposits of South Australia will be conducted in order to test two hypotheses: 1) previously determined species distinctions can be identified using morphologic differences and are not an artifact of varying preservational modes; and 2) Dickinsonia had preferred environmental habitats and was one of the most abundant organism of the Ediacara biota. Data will also be used to address the extent to which size frequency and spatial patterns can inform us about the autecology and synecology of this unique organism. These hypotheses will be tested through four objectives: 1) identify morphological variability in order to investigate speciation; 2) to determine dominance and environmental preference using photographs of entire bed surfaces along with detailed reports of presence, absence, and abundance of Dickinsonia; 3) bed scale observations of size and abundance data will also be documented as well as spatial relations between Dickinsonia and other taxonomic groups to examine the ecologic importance of this ancient organism; and 4) evaluate potential preservation biases in this fossil record. This NSF EAPSI award is funded in collaboration with the Australian Academy of Science.