The Branching Process: A General Conceptual Framework for Addressing Current Ecological and Evolutionary Questions

Classical branching-process theory, developed by Galton and Watson in the nineteenth century and later refined by Fisher and Haldane, provides the formal framework for quantifying the fate of new mutants, new viral and bacterial pathogens, new coloniza-tion of invasive species, etc. It is a powerful tool to quantify and predict the effect of differential reproductive success on the speciation potential of evolutionary lineages. Here, I revisit the conceptual framework of the branching process, detail its mathe-matical development over time, tie up a few historical loose strings, and highlight its potential applications in modern ecology and evolutionary biology.