Von Baer, K
Full Name: Karl Ernst von Baer
Achievements: Comparative embryology
Born: February 28, 1792; Jerwen, Estonia
Died: November 28, 1876; Tartu, Estonia (Aged 84)
Field & Discipline: Science; Biology; Anthropology; Geography
Language: Germany
Father: Magnus Johann von Baer
Mother: Juliane Louise
Siblings: Nine
Spouse: Auguste von Medem
Children: 5 sons, 1 daughter
Education: At home; Cathedral School, Reval; Universities of Dorpat (now Tartu), Berlin, Vienna, Wurzburg
Major Work:
"On the Mammalian Egg and the Origin of Man"
"On the Development of Animals"
Life & Times:
From 1817 to 1834, Von Baer taught anatomy at Konigsberg University. He was made professor of anatomy in 1819 and professor of zoology in 1826. He also taught some anthropology, founded a zoological museum, and served as director of the botanical gardens, and dean and rector of the university.
Von Baer's most important work was in embryology. His discovery of the mammal egg, in the ovary of a dog, ended a centuries-long scientific quest. In the 1600s, English physician [influenced by] Harvey* looked for the eggs of a deer in the animal's uterus, but failed to find them.
Dutch naturalist [influenced by] Swammerdam* had discovered the ovarian follicles which were mistaken by some for mammalian eggs. Von Baer's discovery, supported by findings in other mammalian species, proved that all mammals (and therefore human beings) develop from eggs. In 1827, Von Baer published his discovery in "On the Mammalian Egg and the Origin of Man".
Von Baer's work in vertebrate development was also significant. It was already known that "primary germ layers" (the ectoderm, mesoderm and endoderm) formed in the early development of the chick. Von Baer extended this study to all vertebrates and made several discoveries in the development of vertebrates which related to particular organs or systems of organs.
Von Baer discovered the notochord, and was among the first to realize the significance of neural folds in the central nervous system, although he did not discover how they actually formed the brain and spinal cord. He named and described five primary brain vesicles. He also advanced knowledge about the development and function of the membranes outside the embryo in both chick and mammal.
He coined the term "spermatozoa" (he thought they were parasites) for the organisms in the seminal fluid that had first been described in 1677 by Dutch microscopist [influenced by] Leewenhoek*. In "On the Development of Animals" (1828, 1837), Von Baer described the development of vertebrates from conception to hatching or birth, and formed the basis for comparative embryology.
Before his discoveries, it had been thought embryonic parts were formed within the egg. Von Baer showed that specific structures are not formed until the embryo develops. His findings later influenced the work of English sociologist/philosopher [influenced] Spencer*.
In 1834, von Baer moved to Russia and became a full member in zoology at the Academy of Sciences in St. Petersburg. He worked as a librarian for the foreign division, and also acted as tutor for a short time to the daughters of Grand Duchess Helen Pavlovna, sister-in-law of Tsar Alexander I.
In 1837, he led an Academy expedition to the uninhabited Novaya Zemlya region and became the first naturalist to collect specimens from the area. Over the next 25 years, he went on many more expeditions, in Russia, England, and on the Continent. In 1845, he co-founded the Russian Geographical Society.
In 1846, Von Baer was made Academy member for anatomy and physiology and took over as director of the Academy's anatomical museum, where he put together a large collection of skulls. Although he allowed that a variety of human skulls might have evolved from one common form, he did not accept [rejected theory of] Charles Darwin*'s theory that all species might be descended from one or very few common ancestors.
Von Baer helped found the Russian Entomological Society, and became its first president in 1860. His philosophical base was similar to that of German nature philosopher [work paralleled that of] Johann Wolfgang von Goethe*, who discovered and named the associated science of morphology
Extra Connections: His work related to that of [work related to] Haeckel* and [work related to] TH Huxley*
Assessment: Established the new science of comparative embryology
Oneliner: Karl Von Baer, founder of comparative embryology
Bibliography:
- Dictionary of Scientific Biography.
- Encyclopedia Britannica.