orthogenesis
/ɔrθoʊˈdʒɛnəsɪs/
noun
- A theory that evolution follows a predetermined direction or straight line, rather than being random.
- Orthogenesis was a popular idea in the 19th century, but most scientists now reject it.
- The fossil record was once interpreted as evidence of orthogenesis in horse evolution.
- Some early biologists believed orthogenesis explained why certain traits became more pronounced over generations.