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Karl Ernst von Baer ( February 17 1792 - November 26 1876) was a German- Estonian biologist and the founding father of embryology.
Born in Piibe , Estonia. Educated at the Cathedral School in Tallinn and the University of Tartu. He became a professor at Königsberg University ( Kaliningrad) in 1817 and full professor of zoology in 1821. He studied the embryonal development of animals, discovering the blastula stage of development and the notochord, with Christian Pander described the germ-layer theory of development ( ectoderm, mesodermMesoderm is one of the three germ layers in the early developing embryo, the other two layers being the ectoderm and the endoderm. The mesoderm gives rise to tissues including connective tissue, muscles and the circulatory system. In a developing vertebra, and endodermThe endoderm is one of the three germ layers of the developing embryo, the other two being the ectoderm and the mesoderm. The endoderm gives rise to various tissues including the gastrointestinal tract, respiratory tract, and endocrine glands. Development) and discovered the mammalian ovumFor the video-related acronym, see OVA. An ovum (or loosely, egg or egg cell is a female sex cell or gamete. Both animals and seed plants have ova. The term ovule is used for the ovum of seed plants and for the young ovum of an animal. The word is derived in 1827Events February 20 Battle of Huzaingo February 28 The Baltimore & Ohio Railroad is incorporated, becoming the first railroad offering commercial transportation of both people and freight. March 7 Ellen Turner is abducted The Shrigley Abduction case begins. He laid the foundations of the science of comparative embryology with his book Über Entwickelungsgeschichte der Thiere (1828) and formulated what would later be called the Baer laws:
- The general characters of the group to which an embryo belongs appear in development earlier than the special characters.
- The less general structural relations are formed after the more general, and so on, until the most specific appear.
- The embryo of any given form, instead of passing through the state of other definite forms, on the contrary, separates itself from them.
- Fundamentally the embryo of a higher animal form never resembles the adult of another animal form, but only its embryo.
In 1834 Baer joined the St Petersburg Academy of Sciences, first in zoology (1834-46) and then in comparative anatomyEvolutionary biology Comparative anatomy is the study of similarities and differences in organisms. It is closely related to evolutionary biology (see evolution) and with phylogeny (the evolution of organism development). Two major concepts of comparative and physiology (1846-62). His interests while there were ichthyology, ethnography, anthropology and geography. The last years of his life (1867-76) were spent in Tartu, where he became the one of the leading critics of the theories of Charles DarwinCharles Robert Darwin ( February 12, 1809 April 19, 1882) was an English naturalist whose revolutionary theory laid the foundation for both the modern theory of evolution and the principle of common descent by proposing natural selection as a mechanism..
Baer, Karl Ernst von
Baer, Karl Ernst von
Baer
Baer
