Linking population‐level and microevolutionary processes to understand speciation dynamics at the macroevolutionary scale

Abstract

Although speciation dynamics have been described for several taxonomic groups in distinct geographic regions, most macroevolutionary studies still lack a detailed mechanistic view on how or why speciation rates change. To help partially fill this gap, we suggest that the interaction between the time taken by a species to geographically expand and the time populations take to evolve reproductive isolation should be considered when we are trying to understand macroevolutionary patterns. We introduce a simple conceptual index to guide our discussion on how demographic and microevolutionary processes might produce speciation dynamics at macroevolutionary scales. Our framework is developed under different scenarios: when speciation is mediated by geographical or resource‐partitioning opportunities, and when diversity is limited or not. We also discuss how organismal intrinsic properties and different overall geographical settings can influence the tempo and mode of speciation. We argue that specific conditions observed at the microscale might produce a pulse in speciation rates even without a pulse in either climate or physical barriers. We also propose a hypothesis to reconcile the apparent inconsistency between speciation measured at the microscale and macroscale, and emphasize that diversification rates are better seen as an emergent property. We hope to bring the reader's attention to interesting mechanisms to be further studied, to motivate the development of new theoretical models that connect microevolution and macroevolution, and to inspire new empirical and methodological approaches to more adequately investigate speciation dynamics either using neontological or paleontological data.

Genetic signatures of lineage fusion closely resemble population decline

“…For instance, the inability to reliably infer lineage fusion can complicate conclusions about phylogeographic congruence among co‐distributed species (Garrick et al., 2019 ). Likewise, fusion events may play important roles in adaptive radiations (Marques et al., 2019 ), and affect inferences about macroevolutionary processes such as speciation and extinction rates (Alencar & Quental, 2021 ; Dynesius & Jansson, 2014 ; Rosenblum et al., 2012 ).…”

Geographical and ecological drivers of coexistence dynamics in squamate reptiles

“…Madagascar) in our study raises a concern that the absence of a geographical effect on the coexistence dynamics of lizards may simply be attributed to the potential relatively smaller geographic ranges of lizards compared with snakes in general. This implies that the perception of a geographical area of the same size would differ between lizards and snakes (see Alencar & Quental, 2021). If snakes possess larger geographic ranges, then being on an island, as defined here, might indeed facilitate coexistence.…”

Phylogeography of Himalrandia lichiangensis from the dry-hot valleys in Southwest China

“…Besides, the genetic distribution pattern of Taxus wallichiana suggested that the barrier of the Hengduan and Dabashan mountains may have caused allopatric speciation ( Gao et al., 2007 ). Therefore, early genetic divergence of H. lichiangensis was most likely attributed to the heterogeneous uplift in the STP, and the subsequent microevolutionary processes at the population level may be driven by effects of heterogeneous habitats such as topography, altitude and humidity ( Alencar and Quental, 2021 ).…”