![]() ![]() ![]() Earl described how shallow seas connected islands on the west ( Sumatra, Java, etc.) with the Asian continent and with similar wildlife, and islands on the east such as New Guinea were connected to Australia and were characterized by the presence of marsupials. Earl published his observations in faunal differences between the islands in the Indo-Australian archipelago. One of the earliest descriptions of the biodiversity in the Indo-Australian Archipelago dates back to 1521 when Venetian explorer Pigafetta recorded the biological contrasts between the Philippines and the Maluku Islands (Spice Islands) (on opposite sides of the Wallace's Line) during the continuation of the voyage of Ferdinand Magellan, after Magellan had been killed on Mactan. Historical context The original drawing of the line in Wallace's paper Wallace's line is one of the many boundaries drawn by naturalists and biologists since the mid-1800s intended to delineate constraints on the distribution of the fauna and flora of the archipelago. ![]() Those caused the isolation of different taxonomic groups on islands at present relatively close to each other. The complex biogeography of the Indo-Australian Archipelago is a result of its location at the merging point of four major tectonic plates and other semi-isolated microplates in combination with ancient sea levels. The line runs through Indonesia, such as Makassar Strait between Borneo and Sulawesi (Celebes), and through the Lombok Strait between Bali and Lombok, where the distance is strikingly small, only about 35 kilometers (22 mi), but enough for a contrast in species present on each island. Wallace noticed this clear division in both land mammals and birds during his travels through the East Indies in the 19th century. To the west of the line are found organisms related to Asiatic species to the east, a mixture of species of Asian and Australian origins is present. Huxley that separates the biogeographical realms of Asia and ' Wallacea', a transitional zone between Asia and Australia also called the Malay Archipelago and the Indo-Australian Archipelago. The Wallace line or Wallace's line is a faunal boundary line drawn in 1859 by the British naturalist Alfred Russel Wallace and named by the English biologist T.H. The deep water of the Lombok Strait between Bali and Lombok formed a water barrier even when lower sea levels linked the now-separated islands and landmasses on either side. The probable extent of land at the time of the Last Glacial Maximum, when the sea level was more than 110 m (360 ft) lower than today, is shown in grey. Line separating Asian and Australian fauna Wallace's Line delineates Australian and Southeast Asian fauna. ![]()
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