nounBiology , chiefly • historical
- A theory that variations in evolution follow a particular direction and are not merely sporadic and fortuitous.More example sentences
- Weidenreich tried to explain the seeming contradiction between isolated regional development and the unity of the human species by advancing the notion of orthogenesis, or directed evolution.
- A once-popular hypothesized evolutionary mechanism was orthogenesis, in which change in organisms was due not to natural selection, but to internal directional trends within a lineage.
- In contrast, other scientists imagine channeling, aka orthogenesis, to exist not only for individuals but also for species and for evolution: while there are lots of possibilities, the domain is restricted.
- More example sentences
- Basically, Newell rejected the common view according to which allometry implies nonadaptive, or orthogenetic evolution.
- The fuel in his orthogenetic engine is ‘mutation bias’. Mutation produces novel phenotypes, but it does not produce all novel phenotypes in equal frequency in a given population.
- Most American biologists had a looser expectation - that some progressive, or ‘orthogenetic’, force guided life in certain directions, most notably toward humanity and Anglo-American civilization.
More definitions of orthogenesisDefinition of orthogenesis in:
- The British & World English dictionary