Wallace Line to the west of the Philippines. Wallace's studies in Indonesia demonstrated the emerging theory of evolution, at about the same time as Joseph Dalton Hooker and Asa Gray published essays also supporting Darwin's hypothesis. Understanding of the biogeography of the region centers on the relationship of ancient sea levels to the continental shelves. Wallace's Line is visible geographically when the continental shelf contours are examined; it can be seen as a deep-water channel that marks the southeastern edge of the Sunda Shelf which links Borneo, Bali, Java, and Sumatra underwater to the mainland of southeastern Asia. Australia is likewise connected
Fauna of Asia over 300 amphibian species are also present, including numerous endemics. See also the Indo-Burma biodiversity hotspot. Malesia is a province which straddles the boundary between Indomalaya and Australasia. It includes the Malay Peninsula and the western Indonesian islands (Sumatra, Java, Borneo and others, known as Sundaland), the Philippines, the eastern Indonesian islands, and New Guinea. While the Malesia has much in common botanically, the portions east and west of the Wallace Line differ greatly in land animal species; Sundaland shares its fauna with mainland Asia, while the islands east of the Wallace line either lack land mammals, or are home