The German biologist and natural philosopher Ernst Heinrich Philipp August Haeckel (1834-1919) was famous for his work in evolutionary theory, especially the construction of phylogenetic trees. In the late 19th and early 20th centuries he was as famous as Charles Darwin, whom he admired, though his views were closer to those of Jean Baptiste Lamarck.

Ernst Haeckel was born in Potsdam, Germany, on February 16, 1834, to Carl and Charlotte (Sethe) Haeckel. His father was the chief administrator for religious and educational affairs in Merseburg, while his mother was the daughter of a privy councillor in Berlin. Haeckel thus had the social advantage of growing up in an educated and cultured family. He was publicly educated at the Domgymnasium in Merseburg, graduating in 1852. He then, on the advice of his parents, studied medicine at Berlin, later at Würzburg and Vienna, before returning to Berlin to earn his medical...