Department of Biology, CEES & Evogene, University of Oslo, Oslo, Norway.
Norwegian Institute for Nature Research (NINA), NO-7485 Trondheim, Norway.
Syst Biol. 2022 Aug 10;71(5):1054-1072. doi: 10.1093/sysbio/syab079.
Understanding variation in rates of evolution and morphological disparity is a goal of macroevolutionary research. In a phylogenetic comparative methods framework, we present three explicit models for linking the rate of evolution of a trait to the state of another evolving trait. This allows testing hypotheses about causal influences on rates of phenotypic evolution with phylogenetic comparative data. We develop a statistical framework for fitting the models with generalized least-squares regression and use this to discuss issues and limitations in the study of rates of evolution more generally. We show that the power to detect effects on rates of evolution is low in that even strong causal effects are unlikely to explain more than a few percent of observed variance in disparity. We illustrate the models and issues by testing if rates of beak-shape evolution in birds are influenced by brain size, as may be predicted from a Baldwin effect in which presumptively more behaviorally flexible large-brained species generate more novel selection on themselves leading to higher rates of evolution. From an analysis of morphometric data for 645 species, we find evidence that both macro- and microevolution of the beak are faster in birds with larger brains, but with the caveat that there are no consistent effects of relative brain size.[Baldwin effect; beak shape; behavioral drive; bird; brain size; disparity; phylogenetic comparative method; rate of evolution.].
理解进化率和形态差异的变化是宏观进化研究的目标。在系统发育比较方法的框架内，我们提出了三个明确的模型，将一个特征的进化率与另一个正在进化的特征的状态联系起来。这允许使用系统发育比较数据检验关于表型进化率因果影响的假设。我们开发了一个统计框架，用于用广义最小二乘回归拟合模型，并利用这一框架更普遍地讨论进化率研究中的问题和局限性。我们表明，检测进化率影响的能力很低，因为即使是强烈的因果影响也不太可能解释差异中观察到的变异的百分之几以上。我们通过测试鸟类喙形进化的速度是否受到大脑大小的影响来说明这些模型和问题，这可能是由于鲍德温效应预测的，即假定更具行为灵活性的大脑物种对自身产生更多的新选择，从而导致更高的进化率。从对 645 种鸟类形态计量数据的分析中，我们发现有证据表明，具有较大大脑的鸟类的喙的宏观和微观进化都更快，但需要注意的是，相对大脑大小没有一致的影响。[鲍德温效应；喙形状；行为驱动；鸟类；大脑大小；差异；系统发育比较方法；进化率。]
