Ernst Heinrich Haeckel (1834-1919), German biologist and Darwinist. Haeckel was the first to divide animals into unicellular (protozoan) and multicellular (metazoan) categories. In his studies on evolution, Haeckel proposed that prehistoric creatures resembled the embryos of modern animals. This 'evolutionary recapitulation' has since been disproved. Haeckel used Darwin's theory of evolution (natural selection) to justify the idea that the Germans should be considered a master race. He also coined the words 'ecology', 'ontogeny' and 'phylogeny'.