The fauna and flora of australia are very different from those of the rest of the world. why might this be true?

Australia is a continent that has unique flora and fauna, species that seem weird and very unusual when compared to the rest of the world. The main reason for this is that Australia has been isolated from the rest of the continents for a very long time. After the initial breakup of Pangaea, Australia has been part of Gondwanaland, but Gondwanaland also continued to break apart, so Australia become isolated. Until relatively recently, geologically speaking, Australia had flora and fauna that resembled the South American to a certain point, but South America got connected with North America and that quickly changed.

The flora and fauna in Australia have been evolving independently, in their own unique way, and without any interference from outside. That makes the Australian species also much more vulnerable, as they are not able to cope with the species from the other continents, and unfortunately lot of species have been introduced in Australia by the humans, causing very big damage.