Abstract
How ecological interactions, genetic processes, and environmental variability jointly shape the evolution of species diversity remains a challenging problem in biology. We developed an individual-based model of clade diversification to predict macroevolutionary dynamics when resource competition, genetic differentiation, and landscape fluctuations interact. Diversification begins with a phase of geographic adaptive radiation. Extinction rates rise sharply at the onset of the next phase. In this phase of niche self-structuring, speciation and extinction processes, albeit driven by biotic mechanisms (competition and hybridization), have essentially constant rates, determined primarily by the abiotic pace of landscape dynamics. The final phase of diversification begins when intense competition prevents dispersing individuals from establishing new populations. Species’ ranges shrink, causing negative diversity-dependence of speciation rates. These results show how ecological and microevolutionary processes shape macroevolutionary dynamics and rates; they caution against the notion of ecological limits to diversity, and suggest new directions for the phylogenetic analysis of diversification.
Highlights
How ecological interactions, genetic processes, and environmental variability jointly shape the evolution of species diversity remains a challenging problem in biology
We further develop the model introduced in Aguilée et al.[21] and Gascuel et al.[23] to elucidate whether and how macroevolutionary diversification and the underlying rates of speciation and extinction are controlled by the abiotic factors of landscape geographical structure and dynamics, and the biotic factors of resource competition and genetic differentiation
Our analysis shows how biotic and abiotic factors interact and influence speciation and extinction rates throughout the process of clade diversification
Summary
Genetic processes, and environmental variability jointly shape the evolution of species diversity remains a challenging problem in biology. Mechanistic models of clade diversification that integrate biotic and abiotic factors have begun to emerge[19,20,21,22,23] These models incorporate genetic mechanisms of reproductive isolation in evolving populations of interacting individuals, and allow to relate the process of speciation to ecological characteristics of populations and physical (e.g., geographical) properties of the environment. We further develop the model introduced in Aguilée et al.[21] and Gascuel et al.[23] to elucidate whether and how macroevolutionary diversification and the underlying rates of speciation and extinction are controlled by the abiotic factors of landscape geographical structure and dynamics, and the biotic factors of resource competition and genetic differentiation. Evolution is driven by (i) heritable variation in the traits, (ii) selection shaped by local competition (within geographically connected patches), (iii) migration between geographically connected patches, and (iv) genetic drift at loci where mutation can create neutral, genetically incompatible alleles
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