Department of Earth Sciences, Downing Street, University of Cambridge, Cambridge, CB2 3EQ, UK.
Oxford University Museum of Natural History, Parks Road, University of Oxford, Oxford, OX1 3PW, UK.
Biol Rev Camb Philos Soc. 2024 Feb;99(1):110-130. doi: 10.1111/brv.13014. Epub 2023 Sep 4.
The end-Neoproterozoic transition marked a gradual but permanent shift between distinct configurations of Earth's biosphere. This interval witnessed the demise of the enigmatic Ediacaran Biota, ushering in the structured trophic webs and disparate animal body plans of Phanerozoic ecosystems. However, little consensus exists on the reality, drivers, and macroevolutionary implications of end-Neoproterozoic extinctions. Here we evaluate potential drivers of late-Neoproterozoic turnover by addressing recent findings on Ediacaran geochronology, the persistence of classical Ediacaran macrobionts into the Cambrian, and the existence of Ediacaran crown-group eumetazoans. Despite renewed interest in the possibility of Phanerozoic-style 'mass extinctions' in the latest Neoproterozoic, our synthesis of the available evidence does not support extinction models based on episodic geochemical triggers, nor does it validate simple ecological interpretations centred on direct competitive displacement. Instead, we argue that the protracted and indirect effects of early bilaterian innovations, including escalations in sediment engineering, predation, and the largely understudied impacts of reef-building, may best account for the temporal structure and possible selectivity of late-Neoproterozoic extinctions. We integrate these processes into a generalised model of early eumetazoan-dominated ecologies, charting the disruption of spatial and temporal isotropy on the Ediacaran benthos as a consequence of diversifying macrofaunal interactions. Given the nature of resource distribution in Ediacaran ecologies, the continuities among Ediacaran and Cambrian faunas, and the convergent origins of ecologically disruptive innovations among bilaterians we suggest that the rise of Phanerozoic-type biotas may have been unstoppable.
晚新元古代之交标志着地球生物圈的明显构型逐渐但永久性地转变。这一时期见证了神秘的埃迪卡拉生物群的灭绝，迎来了显生宙生态系统中结构化的营养网和不同的动物体式。然而，对于晚新元古代灭绝的真实性、驱动因素和宏观进化意义，尚未达成共识。在这里，我们通过解决埃迪卡拉地质年代学的最新发现、经典埃迪卡拉大型生物在寒武纪的持续存在以及埃迪卡拉冠群后生动物的存在，来评估晚新元古代更替的潜在驱动因素。尽管人们重新关注晚新元古代是否存在显生宙式“大规模灭绝”的可能性，但我们对现有证据的综合分析并不支持基于阶段性地球化学触发的灭绝模型，也不支持以直接竞争取代为中心的简单生态解释。相反，我们认为早期两侧对称动物创新的长期和间接影响，包括沉积物工程、捕食的加剧以及在很大程度上尚未研究的造礁影响，可能最能说明晚新元古代灭绝的时间结构和可能的选择性。我们将这些过程整合到一个早期后生动物为主导的生态系统的一般模型中，描绘了由于多样化的大型动物相互作用而导致埃迪卡拉海底的空间和时间各向同性的中断。鉴于埃迪卡拉生态系统中资源分布的性质、埃迪卡拉和寒武纪动物群之间的连续性以及两侧对称动物中具有生态破坏性创新的趋同起源，我们认为显生宙型生物群的兴起可能是不可阻挡的。
