Divergent evolution

Divergent evolution is the accumulation of differences among related populations or species, often as they adapt to different environments or selective pressures.

Natural selection: The differential survival and reproduction of organisms because of heritable differences. Different environments favor different inherited traits, driving populations apart.
Darwin's finches: A group of Galápagos birds whose species differ notably in beak form and feeding ecology. Their beak differences track adaptations to distinct food sources on different islands.
Common descent: The proposition that organisms share ancestors through branching lines of descent. Divergence describes how descendants become different while retaining shared ancestry.
Convergent evolution: The independent evolution of similar traits in lineages that are not closely related. It produces resemblance across lineages, whereas divergence produces differences among relatives.
Genetic drift: Random changes in allele frequencies across generations, especially influential in small populations. Chance can amplify differences between separated populations even without contrasting selection.
African cichlids: A diverse group of freshwater fishes, including many species in East African lakes. Their rapid diversification produced distinct feeding forms and mating signals.
Population genetics: The study of genetic variation within populations and how allele frequencies change over time. It provides the framework for tracking genetic differences as populations diverge.
Parallel evolution: The independent evolution of similar traits in related lineages under similar conditions. It resembles divergence in related groups but often yields similar, rather than increasingly different, adaptations.
Allopatric speciation: The formation of new species after geographic separation reduces gene flow between populations. Geographic isolation can let divergence proceed until populations become separate species.
Hawaiian honeycreepers: A radiation of Hawaiian birds descended from a common finch-like ancestor. Their varied bill shapes and diets illustrate divergence across island niches.

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On the Origin of SpeciesRelated: Darwin’s branching model explains how related populations become distinct species.