In 1687 the English mathematician, physicist, and astronomer Isaac Newton published his great work Principia, in which he described the universe as fixed, with Earth and other heavenly bodies moving harmoniously in accordance with mathematical laws. That approach of systematizing and classifying was to dominate biology in the 17th and 18th centuries. One reason was that the 16th-century “fathers of botany” had been content merely to describe and draw plants, assembling an enormous and diverse number that continued to increase as explorations of foreign countries made it evident that every country had its own native plants and animals.