Biologist PZ Myers responded to the institute's "bogus complaint that Olson was lying in the movie" about Ernst Haeckel's drawings of embryos is false. Myers explained the drawings have not been used in recent biology textbooks "other than a mention that once upon a time Haeckel came up with this idea of ontogeny recapitulating phylogeny." Myers and other critics of intelligent design have shown that each of these texts treats Haeckel's theory of ontogeny recapitulating phylogeny as an example of an outdated exaggeration. Myers notes in his rebuttal of the criticism from design proponents that, "I would add that progress in evolutionary biology has led to better explanations of the phenomenon that vertebrate embryos go through a period of similarity: it lies in conserved genetic circuitry that lays down the body plan."