"In 1880, Wallace published the book Island Life as a sequel to The Geographical Distribution of Animals. It surveyed the distribution of both animal and plant species on islands. Wallace classified islands into three different types. Oceanic islands, such as the Galapagos and Hawaiian Islands (then known as the Sandwich Islands) formed in mid-ocean and never part of any large continent. Such islands were characterised by a complete lack of terrestrial mammals and amphibians, and their inhabitants (with the exceptions of migratory birds and species introduced by human activity) were typically the result of accidental colonisation and subsequent evolution. He divided continental islands into two separate classes depending on whether they had recently been part of a continent (like Britain) or much less recently (like Madagascar) and discussed how that difference affected the flora and fauna. He talked about how isolation affected evolution and how that could result in the preservation of classes of animals, such as the lemurs of Madagascar that were remnants of once widespread continental faunas. He extensively discussed how changes of climate, particularly periods of increased glaciation, may have affected the distribution of flora and fauna on some islands, and the first portion of the book discusses possible causes of these great ice ages. Island Life was considered a very important work at the time of its publication. It was discussed extensively in scientific circles both in published reviews and in private correspondence^{[126]" (Wikipedia article on Alfred Russel Wallace, accessed 02-2017).}