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.

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.

Related Topics:
Notochord - Heinz Christian Pander - Caspar Friedrich Wolff - Ectoderm - Mesoderm - Endoderm - 1826 - Ovum - 1928 - 1827

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Baer's laws

He formulated what would later be called the Baer's laws for embryology:

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• 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.

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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.

Related Topics:
Novaya Zemlya - Caspian Sea - North Cape - Lapland - Russian Geographical Society

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Entomology

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

Related Topics:
Entomology - Russian Entomological Society

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Evolution

Baer was evolutionist, however critical towards Darwin's theory. Baer has established a major alternative to the darwinian paradigm in biology.

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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.

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