George Cuvier launched modern vertebrate paleontology. He originated the major classification of living things based on the nervous system: Vertebrata, Articulata, Mollusca, and Radiata. He also proved persuasively that animals did go extinct, which was doubted at the time. He was a Christian who believed God had created the world with all the variety of living things and that all modern species descended from their original pairs.
Cuvier believed that all living things existed in their essential forms without significant evolutionary change, and organisms are functional wholes. He rejected common descent and evolution because any change in form would destroy the functional whole. Cuvier thought that the functional signs of an organism could be detected in any part, and he had an unusual ability to accurately reconstruct animals from small remaining pieces. He also studied strata extensively and would entertain audiences by examining the exterior of a rock that contained a fossil and accurately predicting what they would find when workmen chiseled away to expose the remains inside.
Cuvier began his career as the tutor for the son of a wealthy man, but was invited to move to Paris and appointed to the Napoleonic University of France. He served in various roles throughout his career, spanning Napoleon, three kings, and revolution. He was considered to possess one of the finest minds of his time.