Cuvier's work is considered the foundation of vertebrate paleontology, and he expanded Linnaean taxonomy by grouping classes into phyla and incorporating both fossils and living species into the classification.

In 1830, Cuvier and Geoffroy engaged in a famous debate, which is said to exemplify the two major deviations in biological thinking at the time – whether animal structure was due to function or (evolutionary) morphology.

[13] According to Lee,[13] "The history of mankind was, from the earliest period of his life, a subject of the most indefatigable application; and long lists of sovereigns, princes, and the driest chronological facts, once arranged in his memory, were never forgotten."

In 1802, he became titular professor at the Jardin des Plantes; and in the same year, he was appointed commissary of the institute to accompany the inspectors general of public instruction.

In this latter capacity, he visited the south of France, but in the early part of 1803, he was chosen permanent secretary of the department of physical sciences of the Academy, and he consequently abandoned the earlier appointment and returned to Paris.

[21] Cuvier then devoted himself more especially to three lines of inquiry: (i) the structure and classification of the Mollusca; (ii) the comparative anatomy and systematic arrangement of the fishes; (iii) fossil mammals and reptiles and, secondarily, the osteology of living forms belonging to the same groups.

[19] In 1812, Cuvier made what the cryptozoologist Bernard Heuvelmans called his "Rash dictum": he remarked that it was unlikely that any large animal remained undiscovered.

Despite this, he regarded his personal faith as a private matter; he evidently identified himself with his confessional minority group when he supervised governmental educational programs for Protestants.

A deep-rooted source of his opposition to the gradual transformation of species was his goal of creating an accurate taxonomy based on principles of comparative anatomy.

He studied the mummified cats and ibises that Geoffroy had brought back from Napoleon's invasion of Egypt, and showed they were no different from their living counterparts; Cuvier used this to support his claim that life forms did not evolve over time.

Cuvier, however, in turn criticized how Lamarck and other naturalists conveniently introduced hundreds of thousands of years "with a stroke of a pen" to uphold their theory.

[41] Early in his tenure at the National Museum in Paris, Cuvier published studies of fossil bones in which he argued that they belonged to large, extinct quadrupeds.

[46] This reality, however, did not prevent the rise of a popular legend that Cuvier could reconstruct the entire bodily structures of extinct animals given only a few fragments of bone.

The idea that these bones belonged to elephants living – but hiding – somewhere on Earth seemed ridiculous to Cuvier, because it would be nearly impossible to miss them due to their enormous size.

[49] Cuvier's thinking on extinctions was influenced by his extensive readings in Greek and Latin literature; he gathered every ancient report known in his day relating to discoveries of petrified bones of remarkable size in the Mediterranean region.

He also maintained an archive of Native American observations, legends, and interpretations of immense fossilized skeletal remains, sent to him by informants and friends in the Americas.

He was impressed that most of the Native American accounts identified the enormous bones, teeth, and tusks as animals of the deep past that had been destroyed by catastrophe.

Near the end of his 1796 paper on living and fossil elephants, he said: Contrary to many natural scientists' beliefs at the time, Cuvier believed that animal extinction was not a product of anthropogenic causes.

From these findings, Cuvier and Brongniart concluded that many environmental changes occurred in quick catastrophes, though Earth itself was often placid for extended periods of time in between sudden disturbances.

Along with William Smith's work during the same period on a geological map of England, which also used characteristic fossils and the principle of faunal succession to correlate layers of sedimentary rock, the monograph helped establish the scientific discipline of stratigraphy.

[54] In 1800 and working only from a drawing, Cuvier was the first to correctly identify in print, a fossil found in Bavaria as a small flying reptile,[55] which he named the Ptero-Dactyle in 1809,[56] (later Latinized as Pterodactylus antiquus)—the first known member of the diverse order of pterosaurs.

He writes:[59] This idea is referred to as Cuvier's principle of correlation of parts, which states that all organs in an animal's body are deeply interdependent.

The strongest evidence Cuvier could provide in favour of extinction would be to prove that the fossilized remains of an animal belonged to a species that no longer existed.

[60] Cuvier hoped that his principles of anatomy would provide the law-based framework that would elevate natural history to the truly scientific level occupied by physics and chemistry thanks to the laws established by Isaac Newton (1643 – 1727) and Antoine Lavoisier (1743 – 1794), respectively.

In 1798, Cuvier published his first independent work, the Tableau élémentaire de l'histoire naturelle des animaux, which was an abridgement of his course of lectures at the École du Pantheon and may be regarded as the foundation and first statement of his natural classification of the animal kingdom.

[19] Among living forms he published papers relating to the osteology of the Rhinoceros indicus, the tapir, Hyrax capensis, the hippopotamus, the sloths, the manatee, etc.

[8] Alongside other French naturalists, Cuvier subjected Sarah Baartman, a South African Khokhoi woman exhibited in European freak shows as the "Hottentot Venus", to examinations.

[69] Following Baartman's death, Cuvier sought out and received permission to dissect her body, focusing on her genitalia, buttocks and skull shape.

He was elected chancellor of the university, in which capacity he acted as interim president of the council of public instruction, while he also, as a Lutheran, superintended the faculty of Protestant theology.

[76] The professor of English Wayne Glausser argues at length that the Aubrey-Maturin series of 21 novels (1970–2004) by Patrick O'Brian make the character Stephen Maturin "an advocate of the neo-classical paradigm articulated .. by Georges Cuvier.