Ernst Haeckel studied Medicine in Berlin and Würzburg and got a doctorate in 1857. He went on to acquire a doctorate in Zoology in Jena three years later. He taught Comparative Anatomy in Jena from 1862-1909. Haeckel was a prolific writer and intellectual and a staunch supporter of Darwin 's theory of evolution. However, he was less convinced about Darwin 's theory of natural selection. Haeckel discovered and named several species, invented a number of biological terms still in use today and proposed several biological laws, which however have been abandoned today. He was also known for his public scientific and political debates, as well for his support for monism. Many of his slogans and ideas were appropriated by the Nazis later on.
Richards, Robert J. The Tragic Sense of Life: Ernst Haeckel and the Struggle over Evolutionary Thought.University of Chicago Press , 2009