Digital Object Identifier (DOI)
The origin and expansion of biological diversity is regulated by both developmental trajectories1,2 and limits on available ecological niches3,4,5,6,7. As lineages diversify, an early and often rapid phase of species and trait proliferation gives way to evolutionary slow-downs as new species pack into ever more densely occupied regions of ecological niche space6,8. Small clades such as Darwin’s finches demonstrate that natural selection is the driving force of adaptive radiations, but how microevolutionary processes scale up to shape the expansion of phenotypic diversity over much longer evolutionary timescales is unclear9. Here we address this problem on a global scale by analysing a crowdsourced dataset of three-dimensional scanned bill morphology from more than 2,000 species. We find that bill diversity expanded early in extant avian evolutionary history, before transitioning to a phase dominated by packing of morphological space. However, this early phenotypic diversification is decoupled from temporal variation in evolutionary rate: rates of bill evolution vary among lineages but are comparatively stable through time. We find that rare, but major, discontinuities in phenotype emerge from rapid increases in rate along single branches, sometimes leading to depauperate clades with unusual bill morphologies. Despite these jumps between groups, the major axes of within-group bill-shape evolution are remarkably consistent across birds. We reveal that macroevolutionary processes underlying global-scale adaptive radiations support Darwinian9 and Simpsonian4 ideas of microevolution within adaptive zones and accelerated evolution between distinct adaptive peaks.
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Citation / Publisher Attribution
Nature, v. 542, p. 344-347
This is an accepted manuscript of an article published by Nature Research in Nature. The final authenticated version is available online at: https://doi.org/10.1038/nature21074.
Scholar Commons Citation
Cooney, Christopher R.; Bright, Jen A.; Capp, Elliot J. R.; Chira, Angela M.; Hughes, Emma C.; Moody, Christopher J. A.; Nouri, Lara O.; Varley, Zoë K.; and Thomas, Gavin H., "Mega-Evolutionary Dynamics of the Adaptive Radiation of Birds" (2017). School of Geosciences Faculty and Staff Publications. 1184.
This file details the mapping of Jetz et al. clades to the Prum et al. backbone phylogeny. The table shows the nodes used to attach patch clades from the Jetz et al. stage 2 Hackett tree to the Prum et al. backbone phylogeny.
Supplementary Data 2.zip (794 kB)
This archive contains data files and an R script to combine the backbone (approximately family level) phylogeny of Prum et al. with the species level resolution of the Jetz et al. avian phylogeny.
Supplementary Data 3.zip (253 kB)
This archive contains all alternative genus level phylogenies used in the analyses.
Supplementary Data 4.csv (334 kB)
This file contains the source data for Extended Data Table 1.