Embryology

Embryology is the science of the early development of organisms , between the one-cell stage (generally, but not always, the zygote) and the beginning of free living. Embryology therefore deals with the various steps necessary for the correct and complete formation of the body of a living organism. Born as a descriptive science, modern embryology is involved in studying the molecular mechanisms that underlie the development of the embryo; see also developmental biology, morphogenesis.