Conceptual and empirical bridges between micro- and macroevolution

Abstract

Explaining broad molecular, phenotypic, and species biodiversity patterns necessitates a unifying framework spanning multiple evolutionary scales. We argue here that, although substantial effort has been made to reconcile microevolution and macroevolution, much work remains to identify the links between biological processes at play. We highlight four major questions of evolutionary biology whose solutions require conceptual bridges between micro and macroevolution. We review potential avenues for future research to establish how mechanisms at one scale (drift, mutation, migration, selection) translate to processes at the other (speciation, extinction, biogeographic dispersal) and vice versa. We propose ways in which current comparative methods to infer molecular evolution, phenotypic evolution and species diversification could be improved to specifically address those questions. We conclude that researchers are in a better position than ever before to build a synthesis to understand how microevolutionary dynamics unfold over millions of years.

Evolutionary change is remarkably time-independent across scales

“…A seemingly general pattern with faster evolutionary rate over short timescales, and slower rates over longer timescales has been recognized for decades [1][2][3][4][5] . Such apparent time-dependence has subsequently been documented consistently for nearly every possible measure of evolutionary rate 6 , including rates of morphological evolution, rates of molecular evolution 7 , and rates of lineage formation on phylogenies and in the fossil record (Figure 1). Negative rate-time scaling relationships were initially proposed as an artifact that needed to be taken in to account, in that evolutionary rates over different time intervals were not directly comparable 5 .…”

“…Negative rate-time scaling relationships were initially proposed as an artifact that needed to be taken in to account, in that evolutionary rates over different time intervals were not directly comparable 5 . Yet these negative relationships between evolutionary rate and time continue to generate discussions and stimulate biological hypotheses for shared features of the underlying evolutionary processes that could explain such general time-scaling 6,8 . Recent technical and statistical explanations to these apparent negative rate-time scaling relationships focus on sampling biases 9 , such as a the "push of the past" 6 and model mis-specification 2 .…”

“…Yet these negative relationships between evolutionary rate and time continue to generate discussions and stimulate biological hypotheses for shared features of the underlying evolutionary processes that could explain such general time-scaling 6,8 . Recent technical and statistical explanations to these apparent negative rate-time scaling relationships focus on sampling biases 9 , such as a the "push of the past" 6 and model mis-specification 2 . This puzzling and general phenomenon of apparent widespread negative rate-time scaling relationships has been recently highlighted as a major unsolved challenge in evolutionary biology 2,6,8 .…”

“…Recent technical and statistical explanations to these apparent negative rate-time scaling relationships focus on sampling biases 9 , such as a the "push of the past" 6 and model mis-specification 2 . This puzzling and general phenomenon of apparent widespread negative rate-time scaling relationships has been recently highlighted as a major unsolved challenge in evolutionary biology 2,6,8 . The renewed interest in such apparent timedependence of evolutionary rates has re-kindled long-standing ideas and hypotheses about fundamental disparities between micro-and macroevolution [10][11][12][13][14] .…”

Single-fly assemblies fill major phylogenomic gaps across the Drosophilidae Tree of Life

“…We are working on polymorphism data from wild populations for many (100s) of the genomes featured here, that will be presented in a forthcoming study of population genomic variation across the entire family. The relationship of population genomic variation with broad-scale macro-evolutionary patterns such as species diversity is still largely unknown (Rolland et al, 2023) and this will be a major step towards addressing this fundamental question in evolutionary biology.…”