 On the other hand, Owen’s model cannot be considered genuine species transformism—species do not change historically one into another and the archetype exists in one sense as a quasi-Newtonian “law” governing development in time rather than as an actual historical form. Nonetheless, his integration of comparative anatomy, paleontology, and even embryology into this framework set out a sophisticated model of relationship that was later reinterpreted by Darwin from the viewpoint of his theory of material derivation from common historical ancestors.