英国埃塞克斯大学Jennifer F. Hoyal Cuthill小组揭示了进化衰变时钟对物种形成和物种灭绝的影响。相关论文于2020年12月10日在线发表于《自然》杂志。
研究人员应用机器学习生成了古生代化石时间共现结构的空间嵌入（多维排序），涵盖古生物学数据库中171,231个嵌入物种的1,273,254个事件。这有利于使用多样性趋势同时比较宏观进化破坏。在5％的最显著破坏周期中，研究人员确定了“五大”大规模灭绝事件、7次大规模灭绝和两次大规模灭绝－辐射合并事件和15次大规模辐射。
与强调灭绝后辐射的假设相反，研究发现，按比例最可比的质量辐射和灭绝（例如寒武纪爆炸和二叠纪末期大灭绝）通常在时间上解耦，这驳斥了两者之间存在任何直接因果关系。
此外，除了灭绝，进化辐射本身也会引起进化衰变（模型化的共现概率和接近零时间之间物种的共有分数），研究人员将其描述为破坏性创造。通过对衰变时钟进行计数的超阈值宏观进化衰变时间（物种的共享份额在两次之间≤0.1）进行直接检验，研究人员揭示了约1,860万年古生代平均值的锯齿状波动。由于第四纪时期的衰变时钟时间低于平均水平，即1100万年，现代物种灭绝进一步加剧了物种衰变时钟的负担。
据介绍，破坏性大灭绝产生创造性进化辐射（创造性破坏）的假说对于经典宏观进化概念至关重要。然而，尚未直接定量比较从寒武纪开始至今灭绝和辐射对物种共生的相对影响。
附：英文原文
Title: Impacts of speciation and extinction measured by an evolutionary decay clock
Author: Jennifer F. Hoyal Cuthill, Nicholas Guttenberg, Graham E. Budd
Issue&Volume: 2020-12-09
Abstract: The hypothesis that destructive mass extinctions enable creative evolutionary radiations (creative destruction) is central to classic concepts of macroevolution1,2. However, the relative impacts of extinction and radiation on the co-occurrence of species have not been directly quantitatively compared across the Phanerozoic eon. Here we apply machine learning to generate a spatial embedding (multidimensional ordination) of the temporal co-occurrence structure of the Phanerozoic fossil record, covering 1,273,254 occurrences in the Paleobiology Database for 171,231 embedded species. This facilitates the simultaneous comparison of macroevolutionary disruptions, using measures independent of secular diversity trends. Among the 5% most significant periods of disruption, we identify the ‘big five’ mass extinction events2, seven additional mass extinctions, two combined mass extinction–radiation events and 15 mass radiations. In contrast to narratives that emphasize post-extinction radiations1,3, we find that the proportionally most comparable mass radiations and extinctions (such as the Cambrian explosion and the end-Permian mass extinction) are typically decoupled in time, refuting any direct causal relationship between them. Moreover, in addition to extinctions4, evolutionary radiations themselves cause evolutionary decay (modelled co-occurrence probability and shared fraction of species between times approaching zero), a concept that we describe as destructive creation. A direct test of the time to over-threshold macroevolutionary decay4 (shared fraction of species between two times ≤ 0.1), counted by the decay clock, reveals saw-toothed fluctuations around a Phanerozoic mean of 18.6 million years. As the Quaternary period began at a below-average decay-clock time of 11 million years, modern extinctions further increase life’s decay-clock debt.
DOI: 10.1038/s41586-020-3003-4
Source: https://www.nature.com/articles/s41586-020-3003-4
Nature：《自然》，创刊于1869年。隶属于施普林格·自然出版集团，最新IF：69.504
官方网址：http://www.nature.com/
投稿链接：http://www.nature.com/authors/submit_manuscript.html
本期文章：《自然》：Online/在线发表
