Biogeographic realm

The realms delineate large areas of Earth's surface within which organisms have evolved in relative isolation over long periods of time, separated by geographic features, such as oceans, broad deserts, or high mountain ranges, that constitute natural barriers to migration.

As such, biogeographic realm designations are used to indicate general groupings of organisms based on their shared biogeography.

They are distinct from biomes, also known as major habitat types, which are divisions of the Earth's surface based on life form, or the adaptation of animals, fungi, micro-organisms and plants to climatic, soil, and other conditions.

Beginning in the 1960s, it was used originally in the field of biostratigraphy to denote intervals of geological strata with fossil content demonstrating a specific ecology.

[3] In Canadian literature, the term was used by Wiken[4] in macro level land classification, with geographic criteria (see Ecozones of Canada).