Ontogenesis (Gr. He - Existing, Gennan - To Generate)

Ontogenesis is the complete history of the development of an individual organism from conception to maturity. This process includes various stages that are determined by biological, genetic and environmental factors.

The first stage of ontogenesis begins from the moment of conception. The zygote, formed as a result of the fusion of male and female reproductive cells, begins to divide and goes through several stages of development before becoming an embryo. These stages include morula, blastula, gastrula and neurotula.

At the next stage of development, a three-layer germinal disc is formed, which includes endoderm, mesoderm and ectoderm. All organs and tissues of the body are formed from these layers.

In the process of further development, the embryo forms into a fetus, which continues to develop until birth. After birth, there is a gradual development and maturation of organs and systems of the body, such as the nervous, immune, cardiovascular and others.

Genetic factors play an important role in ontogenesis, since genes determine many aspects of the development and functioning of the body. However, the environment also has a significant influence on the development of the body, including diet, level of physical activity, stress, infections and other factors.

Ontogenesis is a complex process that depends on many factors and can be disrupted by various external and internal factors. Some disturbances in ontogenesis can lead to various pathologies and diseases, such as abnormalities of organ development, genetic diseases and others.

In general, ontogeny is an important process for understanding the development of living organisms and can be used to develop new methods for treating and preventing diseases. Ontogeny is also important in the field of evolutionary biology because it shows how changes in the genome can lead to different forms of life and adaptation to the environment.