Final answer:
At times such as 50,000 years ago, dry land connected Australia, New Guinea, and Tasmania, forming the Sahul continent. This occurred during the ice ages when sea levels were lower, allowing land bridges to connect different regions.
Step-by-step explanation:
At times of major global advance, such as 50,000 years ago, dry land connected Australia, New Guinea, and Tasmania, thus forming the Sahul continent. During the ice ages, sea levels were significantly lower, allowing land bridges to connect islands and continents that are separate in contemporary geography. A noteworthy example is the land bridge that connected New Guinea to Australia, which together with Tasmania, was part of the Sahul continent. This occurred before the inundation that separated these land masses due to rising sea levels following the ice age. The history of human migration and the movement of species across these land bridges have had a profound effect on the biological diversity and human cultural development in those regions.