1. Biology. a. 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.
a hypothetical parallelism between the stages through which
necessarily passes, in spite of secondary conditioning factors.