Clade age and not diversification rate explains species richness among animal taxa
Clade age and not diversification rate explains species richness among animal taxa
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DOI：
10.1086/512135
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发表时间：
2007-04-01
影响因子：
2.9
通讯作者：
Brown, Jonathan M.
中科院分区：
文献类型：
--
作者：
McPeek, Mark A.;Brown, Jonathan M.
动物类群的物种丰富度在不同的系统发育群中表现出显著的差异性。对这种差异的大多数解释是，具有更多物种的分类群具有导致更高的多样性比率(即，更高的物种形成率或更低的灭绝率)的表型或生态。在这里，我们表明，主要动物支系的物种丰富度模式主要是由支系寿命而不是多样性比率决定的：更多样化的类群更古老，因此有更多的时间积累物种。从163个物种水平的分子系统发育计算得出的多样性比率在三个主要动物门(节肢动物门、脊索动物门、软体动物门)内和之间高度一致，与物种丰富度无关。具有更高估计多样化比率的分支更年轻，但物种数量随着分支年龄的增加而增加。一个基于化石的数据集还显示，昆虫和脊椎动物的现存物种总数丰富度与冠群年龄之间存在着强烈的正相关关系。这些发现并没有否定生态或表型在影响多样性比率方面的重要性，但它们确实表明，支系寿命是主要动物生物多样性格局中的主导信号。因此，一些关键的创新可能是通过培养支系寿命而不是通过提高多样化比率来发挥作用的。
Animal taxa show remarkable variability in species richness across phylogenetic groups. Most explanations for this disparity postulate that taxa with more species have phenotypes or ecologies that cause higher diversification rates (i.e., higher speciation rates or lower extinction rates). Here we show that clade longevity, and not diversification rate, has primarily shaped patterns of species richness across major animal clades: more diverse taxa are older and thus have had more time to accumulate species. Diversification rates calculated from 163 species-level molecular phylogenies were highly consistent within and among three major animal phyla ( Arthropoda, Chordata, Mollusca) and did not correlate with species richness. Clades with higher estimated diversification rates were younger, but species numbers increased with increasing clade age. A fossil-based data set also revealed a strong, positive relationship between total extant species richness and crown group age across the orders of insects and vertebrates. These findings do not negate the importance of ecology or phenotype in influencing diversification rates, but they do show that clade longevity is the dominant signal in major animal biodiversity-patterns. Thus, some key innovations may have acted through fostering clade longevity and not by heightening diversification rate.