Alternatives to Darwinian evolution

Alternatives to Darwinian evolution are theories that reject or replace natural selection as the primary explanation for evolutionary change in populations and species.

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Lamarckism: A theory that evolution occurs when organisms pass acquired characteristics to their offspring. It explains adaptation through inheritance of acquired traits rather than selection among inherited variations.
Natural selection: A process in which heritable differences affect survival or reproduction, changing trait frequencies across generations. It is the Darwinian mechanism these alternatives challenge, qualify, or supplement.
Jean-Baptiste Lamarck: A French naturalist who developed an early theory of species transformation through use, disuse, and inheritance. His theory supplied the most influential pre-Darwinian alternative to natural selection.
Punctuated equilibrium: A model proposing long periods of evolutionary stasis interrupted by relatively brief episodes of rapid change. It challenges expectations of uniformly gradual change, though it does not reject natural selection.
Mutationism: A theory that evolutionary change can arise chiefly from discrete mutations rather than gradual selection on small variations. It treats new mutations as potential drivers of major change, not merely raw material for selection.
Genetic drift: Random changes in allele frequencies caused by chance sampling in finite populations. It provides a nonselective mechanism that can drive evolutionary change.
Charles Darwin: An English naturalist who developed the theory of evolution by natural selection. His account became the central target and reference point for later alternatives.
Evo-devo: The study of how changes in development contribute to evolutionary patterns and organismal diversity. Developmental constraints and regulatory changes broaden explanations beyond selection on adult traits.
Orthogenesis: The discredited theory that evolution follows an inherent, directional course independent of adaptive natural selection. It proposes an internal direction to evolutionary change instead of adaptation shaped by selection.
Mutation: A heritable change in genetic material that can create new alleles or alter existing ones. Mutation supplies variation and was treated as a more direct evolutionary force by mutationists.