On September 22, 1741, German zoologist and botanist Peter Simon Pallas was born. Pallas was a pioneer in zoogeography by going beyond merely cataloging specimens with simple descriptions, but included observations of causal relationships between animals and their environment. He looked for hidden regularities in natural phenomena over an extreme range of habitats.
Pallas was born in Berlin, the son of Professor of Surgery Simon Pallas at the Collegium medico-chirurgicum in Berlin. From a very early age, he studied hard and took an interest in natural history, later attending the University of Halle and the University of Göttingen. In 1760, he moved to the University of Leiden and passed his doctor‘s degree at the age of 19.
Pallas traveled throughout the Netherlands and to London, improving his medical and surgical knowledge, as well as examining the countries’ natural history collections. He then settled at The Hague. Pallas published Miscellanea Zoologica (1766), his first scientific work, which included descriptions of several vertebrates new to science which he had discovered in the Dutch museum collections. It immediately attracted wide professional attention, not only because of the richness and originality of the presented empirical data, but also with its precisely stated general theoretical propositions. A planned voyage to southern Africa and the East Indies fell through when his father recalled him to Berlin. There, he began work on his Spicilegia Zoologica (1767–80).
He developed a new system for the classification of animals, based on his theory of historic development in the natural world and his idea that organisms could be represented like a family tree, showing sequential relations among the different taxonomic groups. Praised for its elegance and accuracy by George Cuvier , Pallas’s system was later further validated with the acceptance of the theory of evolution.
In 1767, Pallas accepted an invitation from the St. Petersburg Academy of Sciences and Catherine II of Russia to come to Russia to become a professor at the St Petersburg Academy of Sciences, where he spent the next forty years, leading expeditions into much of unexplored Russia, and writing a series of works on the geology and zoology of the Asian mainland. Between 1768 and 1774, he led an expedition to central Russian provinces, Povolzhye, Urals, West Siberia, Altay, and Transbaikal, collecting natural history specimens for the academy. He explored the Caspian Sea, the Ural and Altai Mountains and the upper Amur River, reaching as far eastward as Lake Baikal. The regular reports which Pallas sent to St Petersburg were collected and published as Reise durch verschiedene Provinzen des Russischen Reichs (Journey through various provinces of the Russian Empire) (1771–1776). The study was immediately translated into Russian, and then into French, Italian, and English. It covered a wide range of topics, including geology and mineralogy, reports on the native peoples and their religions, and descriptions of new plants and animals.
Pallas settled in St Petersburg, becoming a favourite of Catherine II and teaching natural history to the Grand Dukes Alexander and Constantine. He was provided with the plants collected by other naturalists to compile the Flora Rossica (1784–1815), a Russian flora, which can be considered the first real flora of Russia, although it was never completed. At the same time, he started work on his Zoographica Rosso-Asiatica (1811–31), a zoography of Russia and Asia. The Empress bought Pallas’s large natural history collection for 2,000 rubles, 500 more than his asking price, and allowed him to keep them for life. Pallas’s studies extended beyond the limits of traditional natural history. He pondered the general processes and laws related to geology: For example, he presented a theory of the origin of mountains in intraterrestrial explosions. He also made a historical survey of land tracts discovered by the Russians in the stretches of ocean between Siberia and Alaska.
Between 1793 and 1794, Pallas led a second expedition to southern Russia, visiting the Crimea and the Black Sea, where he was accompanied by his daughter and his new wife, an artist, servants, and a military escort. Pallas gave his account of the journey in his P. S. Pallas Bemerkungen auf einer Reise in die Südlichen Statthalterschaften des Russischen Reichs (1799–1801). Catherine II gave him a large estate at Simferopol, where Pallas lived until the death of his second wife in 1810. He was then granted permission to leave Russia by Emperor Alexander, and returned to Berlin, where he died in 1811.
By the end of his life Pallas had produced 170 publications. Most of Pallas’s studies offered no broad scientific formulations; their strength was in the richness and novelty of descriptive information. Charles Darwin referred to Pallas in four of his major works, always with the intent of adding substance to his generalizations. Perhaps the first to publish on the relationships between different plants and animals displayed visually in the form of a tree, he was, however, a firm believer that all organisms arose at one time and that variation was in no way related to environment.  Together with the great mathematician Leonhard Euler, Pallas was a major contributor to the elevation of the St. Petersburg Academy of Sciences to the level of the leading European scientific institutions. The plant genus Pallasia was named for him by Linnaeus and his name is also commemorated in the iron-based meteorite metal Pallasite and a volcano in the Kiril Islands.
At yovisto, you may be interested in a video lecture by Prof. Dr. Mary E. Power, who talks about the achievements of Darwin and explains what happened after Darwin in this field of study.
References and Further Reading:
-  Peter Simon Pallas at Saint-Petersburg.com
-  George Cuvier and the Fossils, yovisto blog, Auf, 23, 2013
-  VUCINICH, ALEXANDER. “Pallas, Peter-Simon.” Encyclopedia of Russian History. 2004. Encyclopedia.com.
-  Pallas, Peter (Pyotr) Simon von (1741-1811), at global plants
-  How a Cobbler became the Princeps Botanicarum – Carl Linnaeus, yovisto blog, May 24, 2012.