Ontogeny: This is the study of history of an individual. Ontogeny is also known as ontogenesis and morphogenesis. Ontogeny describes the origin or the development of an organism - for example from the fertilized egg to the mature form. It covers in whole the study of an organism's lifespan. In more general form, we can say that ontogeny is also defined as the history of structural change in a unity that can be an organism, a cell and a society of organisms.

 The term ontogeny has been used more recently in cell biology to describe the development of various cell types within an organism. Ontogeny include some field of study like as developmental psychology, developmental biology, developmental psychobiology or developmental  cognitive neuroscience. In biology, ontogeny pertains to the developmental history of an organism within his own lifetime, as it is distinct from phylogeny.