KARL ERNST VON BAER

'Karl Ernst von Baer' (February 17 1792 - November 26 1876) was a Baltic German biologist and a founding father of embryology.

Contents

Life

Contributions

Embryology

Baer's laws

Anthropology

Baer's law

Explorer

Entomology

Subjective biology

References

External links

Further reading

Life

Karl Ernst von Baer was born in Piibe manor (), Estonia; many of his ancestors had come from Westphalia. A knight by birthright, his full name was ''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 1812, Baer was a volunteer in the war against Napoleon's invasion, serving as doctor[1].
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 one of the leading critics of the theories of Charles Darwin.
A statue honouring him can be found on Toome Hill (''Toomemägi'') in Tartu. The two kroons (2 ''krooni'') Estonian banknote bears his portrait.

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 completed research "Ovi Mammalium et Hominis genesi" for Saint-Petersburg's Academy of Science (published at Leipzig[2][3]) 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.

Baer's law

The term ''Baer's law'' also refers to the proposition that in the northern hemisphere, erosion occurs mostly on the right banks of rivers, and in the southern hemisphere on the left banks.

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 Geographical Society.

Entomology

Baer contributed to studies in entomology and was a cofounder of the Russian Entomological Society.

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
# Baer, K E v. "Über ein allgemeines Gesetz in der Gestaltung der Flußbetten", ''Kaspische Studien'', 1860, VIII, S. 1–6.

External links

★ Overview of Piibe (Piep) manor in Estonian Manors Portal (with a picture of a memorial stone)

★ Short biography of K.E.v.Baer

★ Estonian banknotes

Further reading

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