Why Australia is not an island?
Australia (continent)
The continent includes a continental shelf overlain by shallow seas which divide it into several landmasses—the Arafura Sea and Torres Strait between mainland Australia and New Guinea, and Bass Strait between mainland Australia and Tasmania. When sea levels were lower during the Pleistocene ice age, including the Last Glacial Maximum about 18,000 BC, they were connected by dry land. During the past 10,000 years, rising sea levels overflowed the lowlands and separated the continent into today's low-lying arid to semi-arid mainland and the two mountainous islands of New Guinea and Tasmania.
History of Oceania
Indigenous Australians are the original inhabitants of the Australian continent and nearby islands. Indigenous Australians migrated from Africa to Asia around 70,000 years ago and arrived in Australia around 50,000 years ago. The Torres Strait Islanders are indigenous to the Torres Strait Islands, which are at the northernmost tip of Queensland near Papua New Guinea. The term "Aboriginal" is traditionally applied to only the indigenous inhabitants of mainland Australia and Tasmania, along with some of the adjacent islands, i.e.: the "first peoples". "Indigenous Australians" is an inclusive term used when referring to both Aboriginal and Torres Strait islanders.