Lineage‐dependent rates of evolutionary diversification: analysis of bivariate ellipses
Lineage‐dependent rates of evolutionary diversification: analysis of bivariate ellipses
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进化多样化的谱系依赖率：双变量椭圆分析
DOI：
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发表时间：
1998
期刊：
影响因子：
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通讯作者：
P. Nealen
中科院分区：
文献类型：
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作者：
R. Ricklefs;P. Nealen
1. 提出了一种基于二元椭圆长轴和短轴计算两种性状进化多样化相对速率的方法。椭圆分析相对于比较数据变异的更常见的异速或回归方法的优势在于，每个性状的多样化都是相对于其他性状的多样化进行估计的。这可以揭示姐妹群体中两种性状相对多样化率的差异，或者通过等级分析，揭示一个世系的历史。
1. A method based on the calculation of major and minor axes of bivariate ellipses to estimate relative rates of evolutionary diversification of two traits is presented. The advantage of ellipse analysis over the more common allometric or regression approaches to variation in comparative data is that diversification of each trait is estimated relative to that of the other. This can reveal differences in the relative rates of diversification of two traits among sister groups or, through hierarchical analysis, over the history of a lineage.
2. Equations are provided for calculating the size, shape and orientation of bivariate ellipses based on the variance–covariance matrix of the original data. Standard errors and biases of these parameters are also quantified.
3. Applications of ellipse analysis to the relationship between egg size and incubation period in birds illustrate differences in the diversification of two traits between independent lineages. Nested analysis of covariance based on taxonomic levels further illustrates how relative rates of evolutionary diversification may vary through the history of a monophyletic group.
4. A simple model incorporating both independent (special) and correlated (general) change in two traits shows how different shapes and orientations of bivariate ellipses can be produced by different rates of evolutionary diversification in special and general genetic factors.
5. Ellipse analysis is a descriptive tool that can clarify patterns of diversification. It cannot distinguish differences in evolutionary responsiveness (phylogenetic constraint) from differences in the selective environment affecting the shape and orientation of the bivariate ellipse. It can, however, provide a more detailed characterization of trait evolution than other comparative methods, taking advantage of the additional information provided by the shape and, in some cases, the dimensions of the bivariate ellipse.