1. the theory that evolution proceeds in a predetermined direction independent of natural selection
Usage: biology; historical scientific theory
2. normal development or growth following a regular pattern
Usage: biology; medicine

Examples

• The concept of orthogenesis was popular among some 19th-century biologists.
• Modern evolutionary theory has largely rejected orthogenesis in favor of natural selection.
• The researcher studied orthogenesis in embryonic development.
• Orthogenesis suggests that evolution follows a predetermined path.
• Scientists now understand that evolution is not driven by orthogenesis.
• The theory of orthogenesis implied that organisms evolve toward greater complexity.