Haeckel, Ernst Heinrich definition of Haeckel, Ernst Heinrich in the Free Online Encyclopedia.

Haeckel, Ernst Heinrich (ĕrnst hīn`rĭkh hĕ`kəl), 1834–1919, German biologist and philosopher. He taught (1862–1909) at the Univ. of Jena. An early exponent of Darwinism in Germany, he evolved a mechanistic form of monism monism (mō`nĭzəm) [Gr.,=belief in one], in metaphysics, term introduced in the 18th cent.
..... Click the link for more information. based on his interpretation of Darwin's theories and set forth in his speculative popular works on science, Generelle Morphologie (1866), The History of Creation (1868, tr. 1906), and The Evolution of Man (1874, tr. 1910). Although many of his conclusions have been proved erroneous, they attracted a large following and stimulated research. He developed a theory of recapitulation recapitulation, theory, stated as the biogenetic law by E. H. Haeckel , that the embryological development of the individual repeats the stages in the evolutionary development of the species.
..... Click the link for more information. , illustrated by his gastraea theory, wherein he postulated a hypothetical ancestral form (gastraea) represented by the gastrula stage of individual development. He is known also for his study of invertebrate marine organisms, especially the Radiolaria and sponges.