The Gulstonian Lectures, on Malignant Endocarditis
The Gulstonian Lectures, on Malignant Endocarditis
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古尔斯顿讲座，关于恶性心内膜炎
作者：
W. Osler
现代物种的系统发育树允许研究导致当今多样性的进化速度。最近对哺乳动物系统发育的分析挑战了白垩纪-第三纪（K/T）界线（65亿年）后哺乳动物爆炸性进化的观点。然而，由于缺乏适当的方法，在最近的过去哺乳动物进化的多样化（物种形成减去灭绝）的速度无法确定。在本文中，我提供了一种方法，揭示了哺乳动物进化的速度直到33万年前才发生变化。在这一恒定时期之后，在3300万年至3000万年之间出现了多样化率的高峰。此后，多元化率一直居高不下，直到8.55亿年前。多元化率显著下降，分别为8.55亿美元和3.35亿美元。对哺乳动物亚群（有袋类、胎盘类和6个最大的胎盘亚群）的调查表明，在33-30亿a，主要由啮齿动物、cetartiodactya和有袋类动物驱动。最近多样化率的下降在所有被分析亚群中都是显著的，但真兽目、鲸趾目和灵长类动物除外。我的可能性方法并不局限于哺乳动物的进化。它提供了一个强大的框架来推断系统发育中的多样化率变化和大规模灭绝事件，例如从当今的物种或病毒数据重建。特别是，该方法对系统发育中的噪声和不确定性具有很强的鲁棒性，可以解释不完整的分类群采样。
Phylogenetic trees of present-day species allow investigation of the rate of evolution that led to the present-day diversity. A recent analysis of the mammalian phylogeny challenged the view of explosive mammalian evolution after the Cretaceous–Tertiary (K/T) boundary (65 Mya). However, due to lack of appropriate methods, the diversification (speciation minus extinction) rates in the more recent past of mammalian evolution could not be determined. In this paper, I provide a method that reveals that the tempo of mammalian evolution did not change until ∼33 Mya. This constant period was followed by a peak of diversification rates between 33 and 30 Mya. Thereafter, diversification rates remained high and constant until 8.55 Mya. Diversification rates declined significantly at 8.55 and 3.35 Mya. Investigation of mammalian subgroups (marsupials, placentals, and the six largest placental subgroups) reveals that the diversification rate peak at 33–30 Mya is mainly driven by rodents, cetartiodactyla, and marsupials. The recent diversification rate decrease is significant for all analyzed subgroups but eulipotyphla, cetartiodactyla, and primates. My likelihood approach is not limited to mammalian evolution. It provides a robust framework to infer diversification rate changes and mass extinction events in phylogenies, reconstructed from, e.g., present-day species or virus data. In particular, the method is very robust toward noise and uncertainty in the phylogeny and can account for incomplete taxon sampling.