Ontogeny (also ontogenesis or morphogenesis) (ontos present participle of 'to be', genesis 'creation') describes the origin and the development of an organism from the fertilized egg to its mature form. Ontogeny's studied in developmental biology, developmental psychology, developmental cognitive neuroscience, and developmental psychobiology.Ontogeny's that branch of life science which deals with the study of origin and development of an organism from fertilized ovum to its mature form. In more… (More on Ontogeny)