Karl Ernst von Baer

Karl Ernst von Baer 1792-1876, Estonian biologist. He was a professor at Würzburg and Königsberg and from 1834 at St. Petersburg. Considered a founder of modern embryology, he discovered the notochord as well as the mammalian ovum. In his History of the Development of Animals (2 vol., 1828-37) he presented the theory of embryonic germ layers (the development of body tissues and organs from definite layers of cells formed in the early embryonic stages) and showed that the development of the embryo in different animals is similar in its early stages. He made these ideas a basis for a general evolutionary theory.

Baer, Karl Ernst von (1792–1876) Estonian-born German biologist and embryologist. He studied medicine and comparative anatomy before becoming professor of zoology at Königsberg University in 1817. Ten years later he discovered the mammalian ovum, and traced its development from the Graafian follicle to the embryo. He demonstrated that similar organs in different animals developed from the same germ layers. He also noted the similarities between the young embryos of widely different species (the biogenetic law), which provided Charles Darwin with important evidence for his theory of evolution.