The wordembryologycan be broken down into its parts in order to define the term. An embryo is the early form of a living thing after fertilization that occurs during the development process. The suffix "ology" means the study of something. Therefore, the term embryology means the study of the early forms of life before they are born.

Embryology is an important branch of biological studies since understanding the growth and development of a species can shed light on how it evolved and how various species are related. Embryology is considered to be a form of evidence for evolution and a way to link various species on the phylogenetic tree of life.

Perhaps the best known example of embryology supporting the idea of evolution of species is the work of a Post Darwin Evolution scientist named Ernst Haeckel. His infamous illustration of several vertebrate species ranging from humans, to chickens, to tortoises show how closely life is all related based on major developmental milestones of embryos. Since the time of his drawing's publication, however, it has come to light that some of his drawings of the different species were somewhat inaccurate in the stages those embryos actually go through during development. Some were still correct, though, and the similarities in development helped to springboard the field of Evo-Devo as a line of evidence to support the theory of evolution.

Embryology is still an important cornerstone of studying biological evolution and can be used to help determine similarities and differences between various species. Not only is it used as evidence for the theory of evolution and the radiation of species from a common ancestor, embryology can also be used to detect some types of diseases and disorders before birth. It is also used by scientists around the world working on stem cell research and fixing developmental disorders.

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What Is Embryology Evolution by Definition? - ThoughtCo