Karl Ernst von Baer
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| Karl Ernst von Baer. |
Karl Ernst von Baer (February 17 1792 - November 26 1876) was a German-Estonian biologist and a founding father of embryology.
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Life
Knight Karl Ernst von Baer was born in Piibe, Estonia, his ancestors had come from Westphalia. His full name is Karl Ernst Ritter von Baer, Edler von Huthorn. He was educated at the Cathedral School in Reval (Tallinn) and the University of Dorpat (Tartu). He continued his education in Berlin, Vienna, and Würzburg where Döllinger introduced him to the new field of embryology. In 1817, he became a professor at Königsberg University (Kaliningrad) and full professor of zoology in 1821, and of anatomy in 1826. In 1829 he taught briefly in St Petersburg, but returned to Königsberg. In 1834 Baer moved back to St Petersburg and joined the St Petersburg Academy of Sciences, first in zoology (1834-46) and then in comparative anatomy and physiology (1846-62). His interests while there were anatomy, ichthyology, ethnography, anthropology and geography. The last years of his life (1867-76) were spent in Dorpat (Tartu), where he became the one of the leading critics of the theories of Charles Darwin.
Contributions
Embryology
He studied the embryonal development of animals, discovering the blastula stage of development and the notochord. Together with Heinz Christian Pander and based on the work by Caspar Friedrich Wolff he described the germ-layer theory of development (ectoderm, mesoderm, and endoderm)as a principle in a variety of species laying the foundation for comparative embryology in the book Über Entwickelungsgeschichte der Thiere (1828). In 1826 Baer discovered the mammalian ovum. The first human ovum was described by Allen in 1928.(1) In 1827 he published "Ovi Mammalium et Hominis genesi" and established that mammals develop from eggs.
Baer's laws
He formulated what would later be called the Baer's laws for embryology:
- 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.
Anthropology
At St Petersburg, Baer established an extensive skull collection and became a proponent and contributor to the (pseudo)science of craniology.
Explorer
Baer was interested in the Northern part of Russia and explored Novaya Zemlya in 1837 collecting biologic specimen. Other travels led him to the Caspian Sea, the North Cape, and Lapland. He was a founder and the first president of the Russian Geographicical Society.
Entomology
Baer contibuted to studies in entomology and was a cofounder of the Russian Entomological Society.
Evolution
Baer was evolutionist, however critical towards Darwin's theory. Baer has established a major alternative to the darwinian paradigm in biology.
Subjective biology
Baer was a pioneer in studying biological time - the perception of time in different organisms. This approach was further developed by Jakob von Uexküll.
References
- Wood C, Trounson A. Clinical In Vitro Fertilization. Springer-verlag, berlin 1984, page 6.
- Medical eponyms (http://www.whonamedit.com/)de:Karl Ernst von Baer