The distribution of living things on the globe provides information about
the past histories of both living things and the surface of the Earth.
This evidence is consistent not just with the evolution of life, but also
with the movement of continental plates around the world-otherwise known
as plate tectonics.
Marsupial mammals are found in the Americas as well as Australia and
New Guinea, shown in brown on the map at right. They are not found swimming across the Pacific Ocean, nor
have they been discovered wandering the Asian mainland. There appear to
be no routes of migration between the two populations. How could marsupials
have gotten from their place of origin to locations half a world away?
Fossils of marsupials have been found in the Antarctic as well
as in South America and Australia.
During the past few decades scientists have demonstrated that what is
now called South America was part of a large land mass called Gondwana, which included Australia and
Antarctica. Click on the map below for a short animation that shows how Gondwana split apart 160 to 90 million years
ago. Marsupials didn't need a migration
route from one part of the world to another; they rode the continents
to their present positions.