78 Scopus citations

Abstract

The relative importance of different modes of evolution in shaping phenotypic diversity remains a hotly debated question. Fossil data suggest that stasis may be a common mode of evolution, while modern data suggest some lineages experience very fast rates of evolution. One way to reconcile these observations is to imagine that evolution proceeds in pulses, rather than in increments, on geological timescales. To test this hypothesis, we developed a maximum-likelihood framework for fitting Lévy processes to comparative morphological data. This class of stochastic processes includes both an incremental and a pulsed component. We found that a plurality of modern vertebrate clades examined are best fitted by pulsed processes over models of incremental change, stationarity, and adaptive radiation. When we compare our results to theoretical expectations of the rate and speed of regime shifts for models that detail fitness landscape dynamics, we find that our quantitative results are broadly compatible with both microevolutionary models and observations from the fossil record.

Original languageEnglish
Pages (from-to)13224-13229
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Volume114
Issue number50
DOIs
StatePublished - Dec 12 2017

Keywords

  • Adaptive landscape
  • Levy process
  • Macroevolution
  • Pulsed evolution

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