Ernst Haeckel

Born Feb. 16, 1834, in Potsdam; died Aug. 9, 1919, in Jena. German biologist.

In 1861, Haeckel became a privatdocent in zoology and comparative anatomy at the University of Jena, and from 1862 to 1909 he was a professor there. He investigated Radiolaria (1862 and 1887), calcareous sponges (1872), and medusae (1879, 1880). Haeckel’s best-known works are those which developed and propagated evolutionary teachings and popularized the fundamentals of natural-science materialism; they include General Morphology (vols. 1-2, 1866), Natural History of Creation (1868), Gastraea Theory (1874-77), Anthropogeny, Or a History of Human Development (1874), and Systematic Philogeny (1894-96). In his work The Riddle of the Universe (1899), whose significance was noted by V. I. Lenin (see Poln. sobr. soch., 5th ed. vol. 18, pp. 370-71), Haeckel defended the materialistic world view as against idealism and agnosticism. On the basis of C. Darwin’s theory on the origin of the species, Haeckel developed his teaching on the laws of the origin and development of organisms. He tried to trace the genealogical relationships among different groups of living beings (phylogeny) and represent these relationships in the form of a genealogical tree. Basing himself on the observations of embryologists, especially A. O. Kovalevskii, Haeckel formulated the gastraea theory, which states that multicellular animals arose from a hypothetical ancestor that resembled a two-layered embryo, a gastrula. According to Haeckel the key to understanding phylogeny is studying ontogeny, the development of the individual organism. Haeckel established the relationship between ontogeny and phylogeny, which had been noted by Darwin earlier, as the biogenetic law. Haeckel was inconsistent in his interpretation of the moving forces of evolution; he tried to join the principles of C. Darwin and J. B. Lamarck eclectically into one teaching and recognized both natural selection and the direct adaptation of organisms to environmental conditions by inheritance of acquired traits. The philosophical and sociopolitical views of Haeckel were also characterized by inconsistency.