 The case of Ernst Haeckel displays this imprecision. He was a leading professor of zoology at an important German university (Jena), and he formed a generation of scientific workers in embryology and natural history who had major impact on the history of the life sciences. From his position, Haeckel was able to develop Darwinism both as a popular movement with social and political extensions, and also as a scientific research program that pursued the study of morphology and comparative embryology in the light of Darwin’s general theory (R.J. Richards 1992: chp. 6, 2008, 2013; Nyhart 1995).