The main biogeographic regions

When the biogeographers of the 19th century looked at the distributions of large numbers of species on the globe, they saw that different species often lived in the same broad areas. They suggested that there are large scale faunal regions on the Earth.

The first map of these faunal regions was drawn for birds by the British ornithologist Philip Lutley Sclater (1829 - 1913), and Alfred Russel Wallace soon generalized Sclater's regions to other groups of animals. The Earth was thus divided up into six main biogeographic regions, shown opposite. The discontinuity between the Oriental and Australian regions is known as the Wallace Line.

Figure: the world has been divided into six main biogeographic areas, according to the similarity of their animals. The discontinuity between the Oriental and Australian regions is known as the Wallace line.