Conservatism and diversification of plant functional traits: Evolutionary rates versus phylogenetic signal
Conservatism and diversification of plant functional traits: Evolutionary rates versus phylogenetic signal
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DOI：
10.1073/pnas.0901635106
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发表时间：
2009-11-17
影响因子：
11.1
通讯作者：
Ackerly, David
中科院分区：
文献类型：
--
作者：
Ackerly, David
生态位保守主义和适应性辐射的概念在进化和生态多样化的研究中发挥了核心作用。就表型进化而言，这两个过程可以被视为一个谱系的两端。然而，没有直接的方法可以对性状进化进行比较分析来识别这些对比场景。表型进化速率的分析在这方面发挥着重要作用，值得更多关注。在本文中，独立对比用于估计布朗运动进化模型下连续性状的进化速率。引入了表型多样化率的单位：为了纪念 J. Felsenstein，felsen 被定义为转化性状值的姊妹类群之间的方差每百万年增加一个单位。使用标准化测量单位有利于进化枝和性状之间的比较。对四到六个木本植物分支（宏碁属、七叶树属、Ceanothus、Arbutoideae、夏威夷半边莲和银剑联盟）的三种功能性状（株高、叶片大小和种子大小）的多样化率进行了估计，这些分支的校准系统发育可用。对于高度和叶子大小，夏威夷银剑联盟的比率比其他考虑的分支高两倍到大约 300 倍。这些结果强调了直接估计性状进化速率对于适应性辐射、生态位保守性和性状多样化的比较分析的价值。
The concepts of niche conservatism and adaptive radiation have played central roles in the study of evolution and ecological diversification. With respect to phenotypic evolution, the two processes may be seen as opposite ends of a spectrum; however, there is no straightforward method for the comparative analysis of trait evolution that will identify these contrasting scenarios. Analysis of the rate of phenotypic evolution plays an important role in this context and merits increased attention. In this article, independent contrasts are used to estimate rates of evolution for continuous traits under a Brownian motion model of evolution. A unit for the rate of phenotypic diversification is introduced: the felsen, in honor of J. Felsenstein, is defined as an increase of one unit per million years in the variance among sister taxa of In-transformed trait values. The use of a standardized unit of measurement facilitates comparisons among clades and traits. Rates of diversification of three functional traits ( plant height, leaf size, and seed size) were estimated for four to six woody plant clades ( Acer, Aesculus, Ceanothus, Arbutoideae, Hawaiian lobeliads, and the silversword alliance) for which calibrated phylogenies were available. For height and leaf size, rates were two to approximate to 300 times greater in the Hawaiian silversword alliance than in the other clades considered. These results highlight the value of direct estimates of rates of trait evolution for comparative analysis of adaptive radiation, niche conservatism, and trait diversification.