Estonian embryologist. Born 1792, died 1876.
After studies of medicine and anatomy at the universities of Dorpat (present-day Tartu) and Würzburg, he became professor at the university of Königsberg.
During his tenure at Königsberg, von Baer carried out seminal studies of the embryonic development of mammals and birds. He was the first to identify the mammalian egg's presence in the ovary. He collated his own discoveries with the general knowledge of the age in a monumental work, Über Entwicklungsgeschichte der Thiere ("On the developmental history of animals", 1828). This work not only laid the foundation of modern embryology as a distinct field of study, it also became an important tool in the development of a science of comparative anatomy, allowing scientists to analyse the relationships between different species of animals.