- Also called orthoselection.evolution of a species proceeding by continuous structural changes in a single lineage without presenting a branching pattern of descent.
- a theory that the evolution of a species in a continuous, nonbranching manner is due to a predetermined series of alterations intrinsic to the species and not subject to natural selection.
- Sociology. a hypothetical parallelism between the stages through which every culture necessarily passes, in spite of secondary conditioning factors.
- evolution of a group of organisms predetermined to occur in a particular direction
- the theory that proposes such a development
- the theory that there is a series of stages through which all cultures pass in the same order