Karl Ernst Ritter von Baer Edler von Huthorn (Russian: Карл Макси́мович Бэр; 28 February [O.S. 17 February] 1792 – 28 November [O.S. 16 November] 1876) was a Baltic German scientist and explorer. Baer was a naturalist, biologist, geologist, meteorologist, geographer, and is considered a, or the, founding father of embryology. He was a member of the Russian Academy of Sciences, a co-founder of the Russian Geographical Society, and the first president of the Russian Entomological Society, making him one of the most distinguished Baltic German scientists.
Life
Karl Ernst von Baer was born into the Baltic German noble Baer family (et) in the Piep Manor (et), Jerwen County, Governorate of Estonia (in present-day Lääne-Viru County, Estonia), as a knight by birthright. His patrilineal ancestors were of Westphalian origin and originated in Osnabrück. He spent his early childhood at Lasila manor, Estonia. He was educated at the Knight and Cathedral School in Reval (Tallinn) and the Imperial University of Dorpat (Tartu). In 1812, during his tenure at the university, he was sent to Riga to aid the city after Napoleon's armies had laid siege to it. As he attempted to help the sick and wounded, he realised that his education at Dorpat had been inadequate, and upon his graduation, he notified his father that he would need to go abroad to "finish" his education. In his autobiography, his discontent with his education at Dorpat inspired him to write a lengthy appraisal of education in general, a summary that dominated the content of the book. After leaving Tartu, he continued his education in Berlin, Vienna, and Würzburg, where Ignaz Döllinger introduced him to the new field of embryology. In 1817, he became a professor at Königsberg University and full professor of zoology in 1821, and of anatomy in 1826. In 1829, he taught briefly in St Petersburg, but returned to Königsberg (Kaliningrad). 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. While embryology had kept his attention in Königsberg, then in Russia von Baer engaged in a great deal of field research, including the exploration of the island Novaya Zemlya. The last years of his life (1867–76) were spent in Dorpat, where he became a major critic of Charles Darwin.
Contributions
Embryology
Von Baer studied the embryonic 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). Baer was inspired by the 1818 dissertation of Louis Sébastien Tredern de Lézérec on the development of the chicken embryo. In 1826, Baer discovered the mammalian ovum. The human ovum was first described by Edgar Allen in 1928. In 1827, he completed research Ovi Mammalium et Hominis genesi for St Petersburg's Academy of Science (published at Leipzig). In 1827 von Baer became the first person to observe human ova. Only in 1876 did Oscar Hertwig prove that fertilization is due to fusion of an egg and sperm cell. Von Baer formulated what became known as Baer's laws of embryology:
General characteristics of the group to which an embryo belongs develop before special characteristics. General structural relations are likewise formed before the most specific appear. The form of any given embryo does not converge upon other definite forms, but separates itself from them. The embryo of a higher animal form never resembles the adult of another animal form, such as one less evolved, but only its embryo.
Permafrost research
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