Thomas Henry Huxley, now often remembered as “Darwin’s bulldog”, wrote an entire book dedicated to crayfish, with no less a goal than showing how the study of crayfish could teach the reader all of zoology: “how the careful study of one of the commonest and most insignificant of animals, leads us, step by step, from every-day knowledge to the widest generalizations and the most difficult problems”. In retrospect, Huxley laid out the argument for model organisms several decades before another Thomas, namely, Thomas Hunt Morgan, started using fruit flies as model organisms, which became a wellspring of biological information in the twentieth century. While biology in the nineteenth century emphasised work on diverse species in the field, biology in the twentieth century was driven by a few model organisms in the lab, whether they were rats or fruit flies or Arabidopsis thaliana.