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
Uerdingen line Uerdingen line The Uerdingen Line (named after Uerdingen by Georg Wenker) is the isogloss within West Germanic languages that separates dialects which preserve the -"k" sound in the first person singular pronoun word "ik" (north of the line) from dialects in which the word final -"k" has changed to word final -"ch" in the word "ich" (IPA ) (south of the line). This sound shift is the one that progressed the farthest north among the consonant shifts that characterize High German and Middle German dialects. The line passes through Belgium, the Netherlands, and Germany. North of the line Low German