Embryology is the study of the early development of animals and plants.
Baer identified the primary cell layers of embryos of mammals, and he was the first to discover the egg of the mammal in the ovary. Baer was born in Estonia. In 1819, he became professor of anatomy at the University of Konigsberg, in Germany. He accomplished his most significant work in embryology there. From 1834 to 1867, Baer worked at the Academy of Sciences in St. Petersburg, Russia.