Understanding the functioning of extinct ecosystems is a complicated knot of ecological, evolutionary, and preservational strands that must be untangled. For instance, anatomical and behavioral differences can profoundly alter fossilization pathways. This is particularly true in exceptionally preserved soft-bodied biotas that record the earliest phases of animal evolution during the Cambrian Explosion and the Ordovician Radiation. Herein, a novel method of data partitioning based on probabilistic modelling is developed to examine these processes for the Walcott Quarry, Burgess Shale, Canada (510Ma), and the Fezouata Shale, Morocco (c. 475Ma). The modelling shows that the mechanism for soft-tissue preservation in the Walcott Quarry is ecologically selective, favoring the endobenthos. This is not found in the Fezouata Shale. Taken in concert with bioturbation data, a new model of comparative preservation is developed based on sedimentary flow dynamics. This suggests that during the Cambrian Explosion and Ordovician Radiation the most exceptional fossils sites must still be calibrated against each other to understand the unfolding evolutionary events and the ecological structuring of ancient animal communities.

了解灭绝生态系统的功能是必须解开的生态、进化和保护链的复杂结。例如，解剖和行为差异可以深刻地改变化石化途径。在保存完好的软体生物群中尤其如此，这些生物群记录了寒武纪大爆发和奥陶纪辐射期间动物进化的最早阶段。在此，开发了一种基于概率建模的新数据分区方法，以检查加拿大伯吉斯页岩的 Walcott 采石场（510Ma）和摩洛哥的 Fezouata 页岩（约 475Ma）的这些过程。建模表明，沃尔科特采石场的软组织保存机制具有生态选择性，有利于底栖动物。这在 Fezouata 页岩中没有发现。结合生物扰动数据，基于沉积流动动力学开发了一种新的比较保存模型。这表明，在寒武纪大爆发和奥陶纪辐射期间，最特殊的化石遗址仍然必须相互校准，以了解正在展开的进化事件和古代动物群落的生态结构。