Devonian climate, sea level and evolutionary events: an introduction
Devonian climate, sea level and evolutionary events: an introduction
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DOI：
10.1144/sp423.15
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发表时间：
2016-08
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影响因子：
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通讯作者：
R. T. Becker;P. Königshof;C. Brett
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作者：
R. T. Becker;P. Königshof;C. Brett
地球的面貌在地质年代中发生了巨大的变化。今天活跃的动态过程，如板块构造和气候变化，从一开始就塑造了地球表面并影响了生物多样性模式。另一方面，生物有能力显著改变地球的水文和地球化学循环、大气和气候、沉积物，甚至地表下深处的坚硬岩石。非生物-生物相互作用是地球系统历史的特征，与生物竞争和食物网一起，是进化变化、创新和生物多样性波动的主要触发因素。在古生代，泥盆纪是一个特别有趣的时间间隔，因为它的特点是“中古生代捕食者革命”（Signor & Brett 1984; Brett 2003）和相关的“浮游动物革命”（Klug et al. 2010），其特点是自由游动的头足类动物大量繁殖，包括最古老的甲壳类动物和鱼类群体（如齿鲨和巨型板皮动物），更先进的脊椎动物的崛起，包括最古老的四足动物(如Blieck et al. 2007, 2010；Niedzwiedzki et al. 2010)，显生代最广泛的珊瑚礁复群（例如Kiessling 2008），以及包括最古老的森林在内的陆地植物的多样化和传播所带来的“土地绿化”（例如Stein et al. 2012; Giesen & Berry 2013），这导致了新的土壤类型和不断变化的风化。这些主要的进化趋势并不是在环境稳定的长时间间隔中展开的，而是在大量重复的、地质上短暂的全球性事件中展开的，这些事件打断了长达数百万年的相对稳定时期，称为生态进化亚单位（EE亚单位：Boucot 1990； Brett & Baird 1995; Brett et al. 2009）。边界事件，即使是强度较低的事件，也会在地方到全球生态系统中产生重大重构，并被视为长期进化模式的关键驱动因素（Brett 2012）。House（1983年、1985年、2002年）、Walliser（1984年、1996年）以及最近的Becker等人（2012年）对这些相互关联的非生物和生物事件以及不同程度的灭绝进行了总结。泥盆纪事件演替总结如图1所示。在frasian - famenian边界（Kellwasser危机）和泥盆纪末期（Hangenberg危机）发生的两次一级大灭绝，其特征是主要化石群（类和目）和完整生态系统（如后生动物珊瑚礁、早期森林）的消失，必须在复杂的全球事件序列背景下进行观察。主要生物危机的离散脉冲/阶段与单个较小规模事件之间存在重要的相似之处。在我们的理解中，二级全球事件的特征是许多群体和生态系统的突然灭绝，包括一些广泛和多样的生物群体（目和科）的完全消失。例如，基底Emsian atopus事件（浮游笔石最终灭绝）、Taghanic危机、Frasnes事件和Lower Kellwasser事件。三级全球事件显示全球范围内的灭绝率上升，通常在较低的分类水平（属和种），但在许多分支和几个生态系统中。例如志留纪-泥盆纪界线Klonk事件，以及Daleje、chotunek、Kacak、Condroz和Annulata事件。第四阶全球灭绝指的是数量相对较少但分布广泛的种群突然消失，这意味着一个全球性而非区域性的触发因素。这一范畴可能包括洛契科维亚-布拉格边界
The face of Planet Earth has changed significantly through geological time. Dynamic processes active today, such as plate tectonics and climate change, have shaped the Earth’s surface and impacted biodiversity patterns from the beginning. Organisms, on the other hand, have the capacity to significantly alter Earth’s hydrological and geochemical cycles, its atmosphere and climate, sediments, and even hard rocks deep down under the surface. Abiotic– biotic interactions characterize Earth’s system history and, together with biotic competition and food webs, were the main trigger of evolutionary change, innovations and biodiversity fluctuations. Within the Palaeozoic, the Devonian was an especially interesting time interval as it was characterized by the ‘mid-Paleozoic predator revolution’ (Signor & Brett 1984; Brett 2003) and the related ‘nekton revolution’ (Klug et al. 2010), characterized by the blooms of free-swimming cephalopods, including the oldest ammonoids, and fish groups (e.g. toothed sharks and giant placoderms), the rise of more advanced vertebrates, including the oldest tetrapods (e.g. Blieck et al. 2007, 2010; Niedzwiedzki et al. 2010), the most extensive reef complexes of the Phanerozoic (e.g. Kiessling 2008), and the ‘greening of land’ by the diversification and spread of land plants, including the oldest forests (e.g. Stein et al. 2012; Giesen & Berry 2013), which resulted in new soil types and changing weathering. These major evolutionary trends did not unfold in a long interval of environmental stability, but in times of numerous and repeated, geologically brief, global events that punctuated prolonged periods, up to several million years in duration, of relative stability, termed ecological-evolutionary subunits (EE subunits: Boucot 1990; Brett & Baird 1995; Brett et al. 2009). The bounding events, even those of lesser intensity, produced major re-structuring in local to global ecosystems and are seen as critical drivers of long-term evolutionary patterns (Brett 2012). These linked abiotic and biotic events and extinctions of different magnitude have been summarized by House (1983, 1985, 2002), Walliser (1984, 1996) and, more recently, by Becker et al. (2012). The Devonian event succession is summarized in Figure 1. Two first-order mass extinctions at the Frasnian–Famennian boundary (Kellwasser Crisis) and at the end of the Devonian (Hangenberg Crisis), characterized by the loss of major fossil groups (classes and orders) and complete ecosystems (e.g. metazoan reefs, early forests), have to be viewed in the context of a complex global event sequence. There are important similarities between discrete pulses/phases of the major biotic crises and individual smaller-scale events. In our understanding, second-order global events are characterized by sudden extinctions in many groups and ecosystems, including the complete disappearance of several widespread and diverse organism groups (orders and families). Examples are the basal Emsian atopus Event, where the planktonic graptolites finally died out, the Taghanic Crisis, Frasnes events and Lower Kellwasser Event. Third-order global events show globally elevated extinction rates, often at lower taxonomic level (genera and species), but within many clades and in several ecosystems. Examples are the Silurian–Devonian boundary Klonk Event, and the Daleje, Chotěc, Kacak, Condroz and Annulata events. Fourth-order global extinctions refer to the sudden disappearance of relatively fewer but widespread groups, which implies a global, not regional, trigger. This category may include the Lochkovian–Pragian boundary