"Haeckel." YourDictionary, n.d. Web. 18 December 2018. <https://www.yourdictionary.com/haeckel>.
Haeckel. (n.d.). Retrieved December 18th, 2018, from https://www.yourdictionary.com/haeckel
Ernst Heinrich 1834–1919
German naturalist who was the first to attempt a genealogical tree of all animals. He was also one of the first scientists to publicly support Darwin's theory of evolution. His own ideas about evolution attracted popular attention, and though they were later disproved, they helped to stimulate biological research.