Ontogeny (also ontogenesis or morphogenesis) is the origin and the development of an organism – for example: from the fertilized egg to mature form. It covers in essence, the study of an organism's lifespan. The word "ontogeny" comes from the Greek ὄντος, ontos, present participle singular of εἶναι, "to be"; and from the suffix -geny, which expresses the concept of "mode of production". In more general terms, ontogeny is defined as the history of structural change in a unity, which can be a cell, an organism, or a society of organisms, without the loss of the organization which allows that unity to exist. More recently, the term ontogeny has been used in cell biology to describe the development of various cell types within an organism.

Ontogeny comprises a field of study in disciplines such as developmental biology, developmental psychology, developmental cognitive neuroscience, and developmental psychobiology.

Within biology, ontogeny pertains to the developmental history of an organism within its own lifetime, as distinct from phylogeny, which refers to the evolutionary history of species. In practice, writers on evolution often speak of species as "developing" traits or characteristics. This can be misleading. While developmental (i.e., ontogenetic) processes can influence subsequent evolutionary (e.g., phylogenetic) processes (see evolutionary developmental biology), individual organisms develop (ontogeny), while species evolve (phylogeny).

John Macaluso is an American drummer born in 1968, who has played for Ark, TNT, Yngwie J. Malmsteen among others. Born in Commack, New York, John started playing drums at age 11. Now having recorded on 32 records and playing on multiple world tours, John continues to write and record music, perform live, do clinics and teach. John Vincent Macaluso, a freshman at St. Croix Country Day School, is 15 as of November 22, 2011.

John began his studies with his friend and mentor, Joe Fanco (Good Rats), who John says, "his playing and teaching changed my life". He later began instruction with under the wing of Rod Morgenstein (Dixie Dregs), Dom Famularo and Tommy Aldridge (Ozzy Ozbourne). At the ambitious age of 18, John left his hometown for California to attend the Percussion Institute of Technology. It was here that he studied under Ralph Humphrey (Frank Zappa), Casey Schuerelle, and Joey Heredia. This is where John says, "My passion with odd times and rhythms and understanding them began". That same year, John was hired for his first tour as well as recording with guitarist Paul Hansen in Germany.