BIOGEOGRAPHIC REGION

area of animal and plant distribution having similar or shared characteristics throughout. It is a matter of general experience that the plants and animals of the land and inland waters differ to a greater or lesser degree from one part of the world to another. Why should this be? Why should the same species not exist wherever suitable environmental conditions for them prevail? Geographic regions around the world that have similar environmental conditions are capable of harbouring the same type of biota. This situation effectively separates the biosphere into biomesecological communities that have the same climatic conditions and geologic features and that support species with similar life strategies and adaptations. The biome is the fundamental unit of which larger biogeographic regions (floral kingdoms and faunal realms) consist. The tropical forest is one type of terrestrial biome; it is located at various points around the planet where climatic and geologic conditions produce similar environments. The tropical forest biome contains the same general kinds of biological communities wherever it occurs; however, the individual species will not be the same from one tropical forest to another. Instead, each forest will support organisms that are ecologically equivalenti.e., different species that have a similar life cycle and have adapted analogously to environmental conditions. Figure 1: Floral kingdoms, subkingdoms, and major regions of the world. Figure 2: Faunal realms and major regions of the world. How the unique distributions of animals and plants in various biomes came to be is not explicable purely through present climatic factors and latitudinal zonation. Geologic events such as continental drift and past climatic conditions must be taken into consideration as well. This is the approach used in historical biogeography to study the distributions of flora and fauna throughout the world (Figures 1 and 2). Additional reading Len Croizat, Panbiogeography; or, An Introductory Synthesis of Zoogeography, Phytogeography, and Geology . . ., 2 vol. in 3 (1958), is dated but must still be admired for its incredible scope and breadth of learning, and his Space, Time, Form: The Biological Synthesis (1962), discusses various topics, including evolution, biology, and biogeography. R. Hengeveld, Dynamic Biogeography (1990), surveys biogeographic methods such as taxonomic clustering techniques, ecological adaptations, species richness estimation, and areography. D.R. Stoddart, On Geography and Its History (1986), is a scholarly yet easily read text on geography and its impact on biology. Gareth Nelson and Don E. Rosen (eds.), Vicariance Biogeography: A Critique (1981), explains the basic principles of the vicariance school.J.C. Briggs, Biogeography and Plate Tectonics (1987), is a region-by-region account of the distribution of plants and animals in the context of geologic history. Ronald Good, The Geography of the Flowering Plants, 4th ed. (1974), discusses phytogeography. The general background for plant geography and ecology can be found in Heinrich Walter, Vegetation of the Earth and Ecological Systems of the Geo-Biosphere, 3rd rev. and enlarged ed. (1985; originally published in German, 5th rev. ed., 1984). Philip Jackson Darlington, Zoogeography: The Geographic Distribution of Animals (1957, reprinted 1982), although dated, may still be regarded as the definitive statement on historical zoogeography. Joachim Illies, Introduction to Zoogeography, trans. from German (1974); and Paul Mller, Aspects of Zoogeography (1974), two introductory texts, summarize both historical zoogeography and biotic regions. George Gaylord Simpson, Splendid Isolation: The Curious History of South American Mammals (1980), explores the origin and evolution of the mammals on this continent. Colin Peter Groves