Haeckel , Ernst Heinrich

(1834–1919) German biologist

The son of a government lawyer, Haeckel was born at Potsdam in Germany and educated at the universities of Warburg, Vienna, and Berlin, where he qualified as a physician in 1858. His main interests lay elsewhere and, after a brief period in practice, he moved to Jena to study zoology. In 1862 he was appointed professor of zoology and comparative anatomy at Jena, a position he held until his retirement in 1909.

Haeckel's contributions to zoological science were a mixture of sound research and speculation often with insufficient evidence. An advocate of monism, which postulated a totally materialistic view of life as a unity, he based his evolutionary ideas on the embryological laws expounded by Karl von Baer. Expanding the idea of his mentor, Johannes Müller, Haeckel argued that the embryological stages of an animal were a recapitulation of its evolutionary history, and indeed that there had once been complete animals resembling the embryonic stages of higher animal forms living today. He formulated a scheme of evolution for the whole animal kingdom, from inorganic matter upward. His studies, with Müller, of marine life, particularly the crystalline radiolarians, encouraged him to compare the symmetry of crystals with the simplest animals, and led him to postulate an inanimate origin for animal life. In 1866 Haeckel anticipated later proof of the fact that the key to inheritance factors lies in the cell nucleus, outlining this theme in his Die Perigenesis der Plastidule (1876; The Generation of Waves in the Small Vital Particles).

Haeckel also proposed the idea that all multicellular animals derived from a hypothetical two-layered (ectoderm and endoderm) animal, the Gastraea – a theory that provoked much discussion. He engaged in much valuable research on marine invertebrates, such as the radiolarians, jellyfish, calcareous sponges, and medusae, and wrote a series of monographs on these groups based largely on specimens brought back by the Challenger Expedition. He was also the first to divide the animal kingdom into unicellular (protozoan) and multicellular (metazoan) animals. An ardent Darwinist, Haeckel made several zoological expeditions and founded the Phyletic Museum at Jena and the Ernst Haeckel Haus, which contains his books, archives, and other effects.

In 1906 the Monist League was formed at Jena with Haeckel as its president. The League held a strong commitment to social Darwinism. Man was seen as part of nature and in no way qualitatively distinct from any other organic form. Human society was as much a creation of natural selection as the bird's wing. To such views Haeckel added a strong anticatholicism, a contempt for politicians, and a forecast of impending doom. After the chaos of World War I, Haeckel's views were taken up by eugenicists, the Volk movement and, more significantly, the National Socialists.