Paul Sarasin, full name Paul Benedict Sarasin (11 December 1856 – 7 April 1929) was a Swiss naturalist and ethnologist. He is known as founder of National parks in Switzerland. Life and work Paul Sarasin studied medicine and natural science at the University of Basel with Leopold Ruetimeyer, where he also met Fritz Sarasin, and at the University of Würzburg. His dissertation had the title "Die Entwicklungsgeschichte der Bithynia tentaculata" and was about the developmental history of a small aquatic snail. Paul Sarasin was a second cousin of Fritz Sarasin. Paul and Fritz did not only work and travel together for scientific purposes but also had a close livelong friendship. Both had their origins in the rich and powerful patrician families (Patriziat), which ruled their native city of Basel at this time. The Sarasins conducted research in various fields within the natural sciences, and they amassed a collection of zoological and geological objects (like Molluscs). They later developed interests both in anthropology and ethnology; they photographed and interviewed people, noted measurements of the human body, recorded their language, and collected works of art. Paul and Fritz Sarasin made several scientific expeditions to Ceylon (now Sri Lanka) and Celebes (now Sulawesi). After their first journey to Ceylon 1883-1886 they stayed 1886-1893 in Berlin for evaluation and publication of results. 1890, 1902 and 1907 they travelled again to Ceylon and 1893-1896 to Celebes. After staying from 1896-1902 in Basel they went from 1902-1903 a second time to Celebes. In Celebes they tried to solve an open scientific question related to the theory of evolution of Charles Darwin and Alfred Russel Wallace, about a detail concerned with the geographical distribution of plants and animals called the Wallace Line, that is whether Celebes belonged in this regard more to Asia or to Australia. A network of scientists publishing in English, German, French and Dutch competed for a solution to this problem. Instead of a sharp line the Sarasins proposed a zone of gradual change and asked for research about the kind of connections of land which would explain the existing populations. In the context of the question of the origin and evolution of man Wallace had proposed a second line, hence called Wallace's other line east of the first line, separating two distinct groups of men: the Malay people in the West and the Papuan people in the East. To clarify this problem the