Edward Drinker Cope (July 28, 1840–April 12, 1897) was an American paleontologist and comparative anatomist.

Cope was born in Philadelphia to Quaker parents. At an early age he became interested in natural history, and in 1859 communicated a paper on the Salamandridae to the Academy of Natural Sciences at Philadelphia. It was about this time that he became affiliated with the Megatherium Club at the Smithsonian Institution in Washington, D.C. He was educated partly in the University of Pennsylvania and, after further study and travel in Europe, was appointed curator to the Academy of Natural Sciences in 1865, a post which he held until 1873. From 1864–1867 he was professor of natural science at Haverford College, and in 1889 he was appointed professor of geology and paleontology by the University of Pennsylvania.

His speciality was the study of the American fossil vertebrata. From 1871–1877 he carried on explorations of the Cretaceous strata of Kansas, and the Tertiary in Wyoming and Colorado. He made known at least 1,000 new species in his lifetime, as well as many genera of extinct vertebrata. Among these were some of the oldest known mammals, obtained in New Mexico, and 56 species of dinosaur, including the Camarasaurus, and the Coelophysis. He was an incredibly prolific publisher, producing more than 1,200 scientific papers in his lifetime. He served on the U.S. Geological Survey in New Mexico (1874), Montana (1875), and in Oregon and Texas (1877). He was also one of the editors of the American Naturalist. He died in Philadelphia.

Cope's competition with Othniel Charles Marsh for the discovery of new fossils became known as the Bone Wars.

In 1994, maverick paleontologist Robert Bakker published an paper in the Journal of the Wyoming Geological Society, attempting to define Cope's body as the holotype of Homo sapiens.

Cope's Law

In evolutionary biology, Cope's rule states that population lineages tend to increase body size over geological time. It is named for Edward Drinker Cope. Genus Equidae is often used to illustrate the rule, with small animals evolving into larger ones; but critics such as Stephen Jay Gould point out a number of shortcomings of this example.

Cope's rule is interesting because it appears to make the apparently paradoxical suggestion that possession of large body size favours the individual but renders the clade more susceptible to extinction.

Writing in Science, Blaire Van Valkenburgh of UCLA and coworkers state:

Cope's rule, or the evolutionary trend toward larger body size, is common among mammals. Large size enhances the ability to avoid predators and capture prey, enhances reproductive success, and improves thermal efficiency. Moreover, in large carnivores, interspecific competition for food tends to be relatively intense, and bigger species tend to dominate and kill smaller competitors. Progenitors of hypercarnivorous lineages may have started as relatively small-bodied scavengers of large carcasses, similar to foxes and coyotes, with selection favoring both larger size and enhanced craniodental adaptations for meat eating. Moreover, the evolution of predator size is likely to be influenced by changes in prey size, and a significant trend toward larger size has been documented for large North American mammals, including both herbivores and carnivores, in the Cenozoic.
—(Science, Vol 30 DOI:10.1126/science.1102417 )

Cope's rule has come under sustained criticism, including the observation that counterexamples to Cope's rule are common throughout geological time. Critics also point out that the so-called rule is worthless without a mechanism; palaeontologist Johnathan R. Wigner has stated that "Cope's Rule is a twisted version of the ... historical-narrative (that is, a just-so story). It takes a perceived historical trend and tries to explain it".