Interest in and detailed studies of development go back to Aristotle, and antedated serious work on evolution. In the 19th century, theories of and information about development played a significant role in evolutionary thought. This wave reached a crest with Emst Haeckel's late 19th century attempted fusion of evolutionary and developmental ideas through the study of comparative embryology via his ‘Biogenetic law’ that ‘Ontogeny recapitulates phytogeny.’ With the rise of experimental methods for studying development, and the separation of the study of heredity from that of development leading to the birth of genetics as a separate discipline, Haeckel's views fell out of favor by the first decade of the 20th century as evolutionary thought took on new directions. (See, e.g., Allen 1979, Gould 1977, and the essays by Hamburger and Churchill in Mayr and Provine (1980)).