Continent continent. From this perspective, the edge of the continental shelf is the true edge of the continent, as shorelines vary with changes in sea level. In this sense the islands of Great Britain and Ireland are part of Europe, while Australia and the island of New Guinea together form a continent. As a cultural construct, the concept of a continent may go beyond the continental shelf to include oceanic islands and continental fragments. In this way, Iceland is considered part of Europe and Madagascar part of Africa. Extrapolating the concept to its extreme, some geographers group the Australian continental plate
Smallest organisms montane environments. There is relatively little data on size variation among individuals, growth from metamorphosis to adulthood or size variation among populations in these species. Additional studies and the discovery of further minute frog species are likely to change the rank order of this list. The dwarf gecko ("Sphaerodactylus ariasae") and the Virgin Islands dwarf sphaero ("S. parthenopion"), two geckos in the genus "Sphaerodactylus", are the world's smallest known reptile species and smallest lizard, with a snout-vent length of . A few "Brookesia" chameleons from Madagascar are equally small, with a reported snout-vent length of 15–18 millimetres for male dwarf