Ontogeny and Phylogeny from an Epigenetic Point of View

The correlation between ontogeny and phylogeny is analyzed through the discussion of four theories on the reality, history, and the epigenetic and the ecological aspects of the mechanism of evolution. The paper goes on to review the historical aspect of evolution as defined by phylogenetic Hennigian classifications, and the creative aspect of evolution which involves von Baer's recapitulationist mechanism. The last section concerns the three epigenetic mechanisms (cell division, cell differentiation, morphogenetic events), and instantiates them in the case of the amphibian embryo. Ontogeny is the mechanical cause of phylogeny, for ontogeny is a mechanical process, while phylogeny is a historical phenomenon.