: Some species experience dramatic shifts during ontogenesis, such as a tadpole’s transformation into a frog [11].
Ontogenesis, derived from the Greek onto ("being") and genesis ("origin") [28], is the sweeping "story" of how a single cell transforms into a complex, mature individual [15, 25]. It encompasses the entire physical, psychological, and behavioral development of an organism throughout its lifespan [25]. The Biological Story: From Zygote to Adult ontogenesis
In the biological sense, ontogenesis describes the chronological phases an organism undergoes to reach its final form: The Biological Story: From Zygote to Adult In
: Ontogenesis doesn't stop at adulthood; it is an ongoing program in the genome that eventually transitions into senescence (aging) [20]. The Human Narrative: Psychology and Culture this includes critical stages like cleavage
: The process begins at fertilization [15]. For many species, this includes critical stages like cleavage, gastrulation (the formation of cell layers), and organogenesis [9].