Macroevolutionary diversification rates show time dependency
Macroevolutionary diversification rates show time dependency
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DOI：
10.1101/396598
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发表时间：
2018-08
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通讯作者：
Luis Francisco Henao Diaz;L. Harmon;Mauro T. C. Sugawara;E. Miller;Matthew W. Pennell
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作者：
Luis Francisco Henao Diaz;L. Harmon;Mauro T. C. Sugawara;E. Miller;Matthew W. Pennell
生命之树的一些分支有着令人难以置信的多样性，而另一些分支则只有少数几个现存的物种。最终，这种差异反映了物种形成和灭绝的平衡。对于为什么这两个过程的速度在不同的谱系之间不同，人们提出了无数的解释，包括生物体本身和它们所生活的环境的各个方面。在这里，我们揭示了这些比率的大量变化与一个简单的因素有关：时间。年轻群体似乎比年长群体积累多样性的速度要快得多。宏观进化速率的这种时间尺度表明，地球上生命的多样化可能存在一些隐藏的共性。几个世纪以来，生物学家一直着迷于不同生物群体之间物种丰富度的巨大差异。多样性的变化被广泛地归因于不同群体之间形成或灭绝的速度的差异。这样的宏观进化率已经在数千个群体中得到了估计，并与种类繁多的生物体特征相关联。在这里，我们分析了大量的系统发育树和化石时间序列，并在这些看似特殊的结果中描述了一个隐藏的普遍性：物种形成和灭绝率遵循一个比例定律，其中两者都取决于它们被测量的群体的年龄，在最年轻的进化枝中速度最快。通过一系列的模拟和敏感性分析，我们证明了时间依赖性不太可能是简单的统计伪影的结果。因此，这种时间尺度很可能是生命之树的一个真正特征，暗示着生物多样性在较长时间内的动态变化可能部分是由令人惊讶的简单而普遍的原则驱动的。
Significance Some branches of the tree of life are incredibly diverse, while others are represented by only a few living species. Ultimately, this difference reflects the balance of the formation and the extinction of species. Countless explanations have been proposed for why the rates of these two processes vary between lineages, including aspects of the organisms themselves and the environments they live in. Here we reveal that a substantial amount of variation in these rates is associated with a simple factor: time. Younger groups appear to accumulate diversity at much faster rates than older groups. This time scaling of macroevolutionary rates suggests that there may be hidden generalities governing the diversification of life on Earth. For centuries, biologists have been captivated by the vast disparity in species richness between different groups of organisms. Variation in diversity is widely attributed to differences between groups in how fast they speciate or go extinct. Such macroevolutionary rates have been estimated for thousands of groups and have been correlated with an incredible variety of organismal traits. Here we analyze a large collection of phylogenetic trees and fossil time series and describe a hidden generality among these seemingly idiosyncratic results: speciation and extinction rates follow a scaling law in which both depend on the age of the group in which they are measured, with the fastest rates in the youngest clades. Using a series of simulations and sensitivity analyses, we demonstrate that the time dependency is unlikely to be a result of simple statistical artifacts. As such, this time scaling is likely a genuine feature of the tree of life, hinting that the dynamics of biodiversity over deep time may be driven in part by surprisingly simple and general principles.