orthogenesis

The hypothesis, now largely discredited, that the evolution of species is linear and driven largely by internal factors rather than by natural selection.

The hypothesis that all cultures evolve in a linear manner from primitivism to civilization.

The direct or immediate origin of species, according to the opinion that it takes place by the ‘organic growth’ of one species into another in a definite line which is predetermined by the constitution which outward circumstances have given to each organism.

A series of similar mutations in successive generations, producing evolutionary change.