Kangaroo evolution - By 110 million years ago, mammals had diverged into two distinct groups, the placental mammals (a group that includes humans and most modern mammals) and the marsupial mammals (a group that includes koalas, kangaroos, wombats, and pouched mice). These groups evolved for millions of years in two increasingly different directions. As we follow the evolution of marsupials, we find their history to be further shaped by the drifting of the continents. The ancient landmasses of Laurasia and Gondwana broke apart to form the continents, isolating one group of marsupials on the continental island of Australia while isolating another group in South America. These separate populations of marsupials were left to evolve in parallel for some time. | Kangaroo evolution - By 110 million years ago, mammals had diverged into two distinct groups, the placental mammals (a group that includes humans and most modern mammals) and the marsupial mammals (a group that includes koalas, kangaroos, wombats, and pouched mice). These groups evolved for millions of years in two increasingly different directions. As we follow the evolution of marsupials, we find their history to be further shaped by the drifting of the continents. The ancient landmasses of Laurasia and Gondwana broke apart to form the continents, isolating one group of marsupials on the continental island of Australia while isolating another group in South America. These separate populations of marsupials were left to evolve in parallel for some time. |