ABSTRACT
Australia has the unique distinction of being both a single country and an island continent. Encompassing a very broad range of land systems and different climatic zones, and experiencing a prolonged period of isolation in its long geological history, Australia is home to an extraordinarily rich and largely endemic biota. The great antiquity and stability of the Australian continent have exposed the land to prolonged weathering. The rich biodiversity values of the biome have stimulated much research and ensured that attention is focused on conservation. Research will probably uncover millions more prokaryote species, with this one group likely to contribute more species than all other groups to both Australian and global biodiversity. The group contains single-celled autotrophs and heterotrophs that live in terrestrial, freshwater and marine environments, either as free-living organisms or as organisms that are associated with plants, fungi, animals or other single-celled organisms as endo- or exobionts.
