Jan Paulus Lotsy

Born 1867, in Dordrecht; died 1931, in Voorburg. Dutch botanist.

Lotsy taught at Johns Hopkins University in Baltimore from 1891 to 1895 and at Rhein University in Leiden from 1904 to 1909 and also served as director of the latter’s herbarium. He traveled in India (1895-1900), the United States (1922), Australia and New Zealand (1925), South Africa (1926-27), and Egypt (1930). He studied the flora of Italy and Switzerland. Lotsy devised a phylogenetic system of the plant world. He proposed a metaphysical theory of “evolution with constancy of species.” He thought that species are constant and unchangeable, because genes are constant and unchangeable. According to Lotsy, evolution, particularly speciation, consists of crosses between species that lead to new combinations of unchanged hereditary material. Natural selection, according to Lotsy, destroys only those organisms that have not adapted; it is not a creative factor in evolution.