Macroevolutionary Rates

by

Daniel L. Rabosky, Graham J. Slater

• LAST REVIEWED: 13 January 2014
• LAST MODIFIED: 13 January 2014
• DOI: 10.1093/obo/9780199941728-0009

Introduction

Many important questions in evolutionary biology are ultimately questions about evolutionary rates. Why do some kinds of organisms have more species than others? Why do some groups undergo striking adaptive radiations, but others persist for hundreds of millions of years as living fossils? Why do some groups have much more ecological or morphological diversity than others? What, if anything, limits the number of species on earth? These are complex and multidimensional questions, but they share a common underlying feature: all are, to some degree, questions about rates of evolutionary change that occur across geological timescales. This article addresses the concept of “macroevolutionary rates,” which can be defined as the rate of an evolutionary process (especially morphological evolution, speciation, and extinction) as measured over geological or macroevolutionary timescales. Macroevolutionary rates do not necessarily cause a particular pattern in the organization of biological diversity. They are best viewed as a statistical summary of evolutionary dynamics as realized across deep time. Their behavior can provide considerable insight into the processes underlying evolutionary change, but the rates themselves are not necessarily a mechanism for change that can be considered independently of lower-level processes that occur at ecological or population-level scales of biological organization. The literature on macroevolutionary rates initially emphasized patterns in the fossil record but has grown considerably in recent years in response to the ubiquity of time-calibrated phylogenetic trees. The bibliography presented here focuses on two forms of macroevolutionary rate variation: species diversification (speciation and extinction) and phenotypic evolution (morphological and ecological trait change). The readings span a broad range of methodological, conceptual, and statistical material. This literature includes examples of key questions that are addressed using macroevolutionary rates, statistical foundations for studying macroevolutionary rates, and the relationship between microevolutionary and macroevolutionary rates.

General Overviews

A number of papers have provided broad and synthetic overviews of macroevolutionary rates and their variation in nature. Due to the breadth of the topic, most reviews have addressed particular components of macroevolutionary rates, such as the statistical estimation of morphological rates. O’Meara 2012 provides a readable introduction to three fundamental statistical models that underlie most phylogenetic studies of macroevolutionary rates, and Roopnarine 2003 reviews non-phylogenetic estimates of morphological evolution rates. Glor 2010 discusses how phylogenetic studies of diversification form enhance our understanding of adaptive radiation. Nee 2006 looks at one of these models (the birth-death process) in greater detail and shows how it has been used to address a range of important questions in macroevolution. Ricklefs 2007 discusses the estimation of species diversification rates from phylogenetic data, and Coyne and Orr 2004 provides a conceptually important discussion of the causes of macroevolutionary speciation rate variation. Jablonski 2008 discusses traits that influence rates of speciation and extinction in light of the concept of “species selection.” Species selection is also discussed at length in the final chapter of Coyne and Orr 2004, where the authors suggest that it is potentially a major factor shaping large-scale evolutionary trends.

• Coyne, J. A., and H. A. Orr. 2004. Speciation. Cambridge, UK: Sinauer.

  Most of this book is focused on the evolution of reproductive isolation, but chapter 12 (pp. 411–445) is an outstanding discussion of the causes of variation in macroevolutionary speciation rates. A highly recommended starting point for trying to understand why species richness varies among different kinds of organisms.

• Glor, R. E. 2010. Phylogenetic insights on adaptive radiation. Annual Review of Ecology Evolution and Systematics 41:251–270.

  DOI: 10.1146/annurev.ecolsys.39.110707.173447

  An excellent review of adaptive radiation that discusses how phylogenetic estimates of macroevolutionary rates can inform our understanding of this iconic process in evolution.

• Jablonski, D. 2008. Species selection: Theory and data. Annual Review of Ecology Evolution and Systematics 39:501–524.

  DOI: 10.1146/annurev.ecolsys.39.110707.173510

  A clear explanation of the process of species selection and a roadmap for future research. Species selection occurs when the frequency of lineages with certain types of traits (e.g., geographic range size) varies through time as a result of the effects of those traits on rates of speciation and/or extinction.

• Nee, S. 2006. Birth-death models in macroevolution. Annual Review of Ecology Evolution and Systematics 37:1–17.

  DOI: 10.1146/annurev.ecolsys.37.091305.110035

  An overview of the history and use of the stochastic birth-death process in macroevolution.

• O’Meara, B. C. 2012. Evolutionary inferences from phylogenies: A review of methods. Annual Review of Ecology, Evolution, and Systematics 43:267–285.

  DOI: 10.1146/annurev-ecolsys-110411-160331

  Divides methods for studying macroevolutionary rates into three general statistical models: continuous-time Markov processes with finite state space, the multivariate normal density, and the birth-death process. An excellent introduction to the underlying unity of major classes of methods that are used to study macroevolutionary patterns on phylogenies.

• Ricklefs, R. E. 2007. Estimating diversification rates from phylogenetic information. Trends in Ecology and Evolution 22:601–610.

  DOI: 10.1016/j.tree.2007.06.013

  A general overview of methods for studying speciation and extinction from phylogenetic trees with a strong conceptual focus. Discusses evidence suggesting that phylogenetic diversification patterns are often inconsistent with simple random walk models of speciation and extinction.

• Roopnarine, P. D. 2003. Analysis of rates of morphologic evolution. Annual Review of Ecology, Evolution, and Systematics 34:605–632.

  DOI: 10.1146/annurev.ecolsys.34.011802.132407

  An overview of methods for measuring morphological rates and a discussion of the significance of rate measurements at different timescales. Noteworthy for advocating a need to incorporate a phylogenetic perspective into paleontological rate estimates.