It was named after Carl Bergmann who described it in 1847.[11][12][13][14][15] Cope's rule states that animal population lineages tend to increase in body size over evolutionary time. The rule is named for the palaeontologist Edward Drinker Cope.[16][17] Deep-sea gigantism, noted in 1880 by Henry Nottidge Moseley,[18] states that deep-sea animals are larger than their shallow-water counterparts. In the case of marine crustaceans, it has been proposed that the increase in size with depth occurs for the same reason as the increase in size with latitude (Bergmann's rule): both trends involve increasing size with decreasing temperature.[19] Dollo's law of irreversibility asserts that once an organism has evolved in a certain way, it will not return exactly to a previous form.