Ernst Heinrich Philipp August Haeckel (Born::February 16, 1834 — Died::August 9, 1919) was a German zoologist and contemporary of Charles Darwin. In believing Darwin's proposed evolutionary theory to be correct, Haeckel began performing his own research to bolster the theory. Ernst Haeckel was so persistent with his constant passion to defend evolution and prove it fact, he earned several nicknames such as "Darwin’s Bulldog on the Continent" and "the Huxley of Germany." 
Research and Forgery
Based on his findings, Haeckel proposed a corollary, which he called the theory of recapitulation. Haeckel's theory stated that embryonic animals go through a "mini-evolution" within their development in the womb. For example, Haeckel claimed that a developing human embryo moved through stages where it had fish-like characteristics (including gill-slits), then amphibian characteristics (such as a tail), then mammalian, and so on—retracing the Darwinian evolutionary path life has come from. Science has since largely discredited recapitulation. For instance, what appears in an embryonic human to be gill-slits are nothing of the sort; they are actually the developmental form of a mammalian pharynx.
While Haeckel's research appeared to support his theory to some extent, he had the hubris to "doctor" his evidence. In the drawings he published to support his work, Haeckel exaggerated the similarities between embryonic forms of different species. Where only minor or slight similarities seemed to exist, he "adjusted" the appearance to further the illusion of his theory. Haeckel had modified the negatives that he used to make the drawings. Journalist Maximilian Harden forced Haeckel to respond to whether he did tamper with the negatives or not. Haeckel confessed to the fact that he did re-touch the negatives, "Without the intent to defraud, but to make the truth more tangible," .
Unfortunately, Haeckel's drawings continued to be put into science texts, indeed college textbooks since long after they had been proven fraudulent and the theory behind them discarded. The net effect was generations of students who grew up believing Haeckel's work was legitimate and factual. Consequently evolution was also given a special standing and seen as factually proven even more so. (If an embryo's evolutionary existence is recapitulated [the belief held by the recapitulation theory], then of necessity the embryo must have an evolutionary existence.)
- Kunstformen der Natur,
- The History of Creation (Natürliche Schöpfungs-geschichte) published in German in 1868, English in 1876 under The History of Creation: Or The Development of the Earth and Its Inhabitants by the Action of Natural Causes.Download PDF.
- Ernst Haeckel: Evangelist for evolution and apostle of deceit by Russell Grigg. Creation 18(2):33–36 March 1996
- Darwin's Failed Predictions, Slide 7: "Evolving views of embryology" (from JudgingPBS.com) by Casey Luskin. December 30, 2007.
- Gill slits & Biogenetic Law video documentary of college textbooks from the 20's to the 90's containing "gill slits" and Haeckel charts.
- Haeckel Lithographs Wikimedia Commons
- Accused of Fraud, Haeckel Leaves the Church. news paper article New York Times. November 27, 1910 (PDF format)
- Encyclopedia Britannica. 2007. Britannica Concise Encyclopedia. 2 Dec. 2007 Ernst Haeckel