AP BIOLOGY

Detailed explanation-1: -How did kangaroos end up in Australia and nowhere else in the world? Quite simply, they evolved there. Australia is an island continent, so its evolutionary development took place independently of other lands. In particular, its mammals evolved in the marsupial form rather than the placental.

Detailed explanation-2: -Those marsupials evolved into many different groups and species. About 15 million years ago, kangaroos started to appear. Their ancestors were opossum-like creatures that lived in the trees. Many types of species died out over time, but today, around 250 species of marsupial live in Australia.

Detailed explanation-3: -Kangaroos and wallabies are marsupials that belong to a small group of animals called macropods. They are only found naturally in Australia and Papua New Guinea. Most macropods have hind legs larger than their forelimbs, large hind feet and long muscular tails which they use for balance.

Detailed explanation-4: -Close to 70% of the 334 extant species occur on the Australian continent (the mainland, Tasmania, New Guinea and nearby islands). The remaining 30% are found in the Americas-primarily in South America, thirteen in Central America, and one species, the Virginia opossum, in North America, north of Mexico.