Variations of this idea became the standard understanding of the Middle Ages and were integrated into Christian learning, but Aristotle did not demand that real types of organisms always correspond one-for-one with exact metaphysical forms and specifically gave examples of how new types of living things could come to be.
Variationer af denne idé blev standardforståelse i middelalderen, og blev integreret i kristen læring, men Aristoteles krævede ikke, at reelle typer af organismer altid svarede én-til-én med nøjagtige metafysiske former, og gav specifikke eksempler på, hvordan nye typer af levende ting kunne komme til at være.