what is fertilisation

Fertilization, also known as fertilisation, is the process of the fusion of gametes to give rise to a new individual organism or offspring and initiate its development. It is the union of a paternal sperm nucleus with a maternal egg nucleus to form the primary nucleus of an embryo. This process occurs when a sperm from a male meets an ovum from a female and forms a zygote, marking the beginning of pregnancy. Fertilization is a complex multi-step process that is complete in 24 hours, and its function is to create a diploid (2N) zygote. In humans, fertilization usually occurs in the ampulla of the fallopian tube, producing a single-celled zygote, which is the first stage of life in the development of a genetically unique organism, and initiates embryonic development.