This textbook introduces graduate students and researchers to the theory and modeling of speciation, examining how genetic and ecological processes contribute to the formation of new species. Using mathematical models alongside biological concepts, it provides a structured approach to understanding the mechanisms that drive evolutionary divergence and reproductive isolation.The main text opens with the theory of genetic incompatibilities, with particular attention to the Dobzhansky-Muller model as an explanation for the evolution of reproductive isolation, while self-contained appendices provide the foundations of population genetics, covering genetic variation, mutation, genetic drift, natural selection, and their mathematical formulations. Readers are then introduced to key models of speciation, including the two-island model, which illustrates the effects of geographic isolation and provides insight into waiting times to speciation."Subsequent chapters explore the relationship between adaptation and speciation through topics such as Fisher's geometric model, ecological speciation, and mutation-order speciation together with speciation by sexual selection, the genomic architecture of divergence under gene flow, and the evolution of assortative mating. The book concludes with discussions of hybrid zones, character displacement, hybrid speciation, population persistence across the geographic cycle of speciation, biodiversity dynamics, phylogenetic comparative methods, and emerging directions in speciation research. Bringing together established theory and contemporary perspectives, this text provides a coherent framework for understanding the processes that generate and maintain biological diversity.
