title: Generation and maintenance of gradients in taxonomic diversity.
abstract: Latitudinal gradients in diversity of organisms represent an equilibrium distribution for at least the last 270 x 10(6) years. Faunas endemic to tropical regions evolved significantly faster than extra-tropical faunas. The latitude-dependent difference in rates of evolution also represents an equilibrium condition for at least the last 270 x 10(6) years and has consequences for paleontological correlation of rocks because the attainable resolution depends on rate of evolution and will thus be greater in tropic regions than in extra-tropical ones.
authors.forename: F G
authors.initials: FG
authors.lastname: Stehli
authors.forename: R G
authors.initials: RG
authors.lastname: Douglas
authors.forename: N D
authors.initials: ND
authors.lastname: Newell