Endemism describes species that are native to a particular geographic area or continent. Examples of endemism in Australia are the koala and the red kangaroo, both of which are not naturally found anywhere else in the world.
Endemism usually occurs in areas that are isolated in some way.
Australia has been isolated from other continents for tens of millions of years, resulting in a high level of endemism. Endemism occurs when populations of one species are separated so they cannot interbreed. Both populations continue to breed and evolve separately. In time, it is possible they will become two separate species. This evolution of new species is called speciation.