Ontogeny is the origin and the development of an organism
In biology, an organism is any contiguous living system . In at least some form, all organisms are capable of response to stimuli, reproduction, growth and development, and maintenance of homoeostasis as a stable whole.An organism may either be unicellular or, as in the case of humans, comprise...

 – for example: from the fertilized
Fertilisation is the fusion of gametes to produce a new organism. In animals, the process involves the fusion of an ovum with a sperm, which eventually leads to the development of an embryo...

An ovum is a haploid female reproductive cell or gamete. Both animals and embryophytes have ova. The term ovule is used for the young ovum of an animal, as well as the plant structure that carries the female gametophyte and egg cell and develops into a seed after fertilization...

 to mature
Mature is the adjectival form of maturity, which has several meanings.Mature may also refer to:*"Mature 17+", a rating in the Entertainment Software Rating Board video game rating system*Mature, a character from The King of Fighters series...

 form. It covers in essence, the study of an organism's lifespan. The word "ontogeny" comes from the Greek ὄντος, ontos, present participle genitive singular neuter 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
Cell biology
Cell biology is a scientific discipline that studies cells – their physiological properties, their structure, the organelles they contain, interactions with their environment, their life cycle, division and death. This is done both on a microscopic and molecular level...

 to describe the development of various cell types within an organism.

Ontogeny comprises a field of study in disciplines such as developmental biology
Developmental biology
Developmental biology is the study of the process by which organisms grow and develop. Modern developmental biology studies the genetic control of cell growth, differentiation and "morphogenesis", which is the process that gives rise to tissues, organs and anatomy.- Related fields of study...

, developmental psychology
Developmental psychology
Developmental psychology, also known as human development, is the scientific study of systematic psychological changes, emotional changes, and perception changes that occur in human beings over the course of their life span. Originally concerned with infants and children, the field has expanded to...

, developmental cognitive neuroscience
Developmental Cognitive Neuroscience
Developmental cognitive neuroscience is an interdisciplinary scientific field at the boundaries of neuroscience, psychology, social neuroscience, developmental science, and cognitive science.-Origins of the discipline:...

, and developmental psychobiology
Developmental psychobiology
Developmental psychobiology is an interdisciplinary field, encompassing developmental psychology, biological psychology, neuroscience and many other areas of biology. The field covers all phases of ontogeny, with particular emphasis on prenatal, perinatal and early childhood development...


Within biology, ontogeny pertains to the developmental history of an organism within its own lifetime, as distinct from phylogeny, which refers to the evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...

ary history of species. In practice, writers on evolution often speak of species as "developing" traits or characteristics. This can be misleading. While developmental or ontogenetic processes can influence subsequent evolutionary or phylogenetic processes (see evolutionary developmental biology
Evolutionary developmental biology
Evolutionary developmental biology is a field of biology that compares the developmental processes of different organisms to determine the ancestral relationship between them, and to discover how developmental processes evolved...

), individual organisms develop (ontogeny), while species evolve (phylogeny).

See also

  • Recapitulation theory
    Recapitulation theory
    The theory of recapitulation, also called the biogenetic law or embryological parallelism—and often expressed as "ontogeny recapitulates phylogeny"—is a disproven hypothesis that in developing from embryo to adult, animals go through stages resembling or representing successive stages...

    , the idea that ontogeny recapitulates phylogeny
  • Organogenesis
    In animal development, organogenesis is the process by which the ectoderm, endoderm, and mesoderm develop into the internal organs of the organism. Internal organs initiate development in humans within the 3rd to 8th weeks in utero...

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