Fractal branching organizations of Ediacaran rangeomorph fronds reveal a lost Proterozoic body plan
Fractal branching organizations of Ediacaran rangeomorph fronds reveal a lost Proterozoic body plan
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DOI：
10.1073/pnas.1408542111
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发表时间：
2014-09-09
影响因子：
11.1
通讯作者：
Morris, Simon Conway
中科院分区：
文献类型：
--
作者：
Cuthill, Jennifer F. Hoyal;Morris, Simon Conway
埃迪卡拉纪范围型叶状体的分支形态在其他复杂的大型生物中没有确切的对应物。因此，这些化石提出了关于生长模式、功能形态、进食模式和适应性优化的主要问题。在这里，使用参数Lindenmayer系统，rangeomorph形态的正式模型揭示了一个分形的身体计划，其特征在于自相似，轴向，顶端，交替分支。11个分类群的连续形态重建表明了基于3D空间填充策略的自适应辐射。的分形体计划的rangeomorphs的表面积最大化，符合扩散营养吸收的水柱（营养）。的rangeomorph形态，进化和灭绝的谜团解决的认识，他们适应性地优化独特的生态和地球化学条件，在晚元古代。与寒武纪大爆发有关的海洋条件的变化决定了它们的命运。
The branching morphology of Ediacaran rangeomorph fronds has no exact counterpart in other complex macroorganisms. As such, these fossils pose major questions as to growth patterns, functional morphology, modes of feeding, and adaptive optimality. Here, using parametric Lindenmayer systems, a formal model of rangeomorph morphologies reveals a fractal body plan characterized by self-similar, axial, apical, alternate branching. Consequent morphological reconstruction for 11 taxa demonstrates an adaptive radiation based on 3D space-filling strategies. The fractal body plan of rangeomorphs is shown to maximize surface area, consistent with diffusive nutrient uptake from the water column (osmotrophy). The enigmas of rangeomorph morphology, evolution, and extinction are resolved by the realization that they were adaptively optimized for unique ecological and geochemical conditions in the late Proterozoic. Changes in ocean conditions associated with the Cambrian explosion sealed their fate.