The biogeographical data is one of the most robust supports for Darwin’s theory of natural selection. The distribution and diversity of species are explained best by evolution and substantial changes to the planet over tens of millions of years. Species that live in similar habitats experience similar environmental selection pressures and will likely evolve similar adaptations. The species may look and behave much alike despite being entirely unrelated. This convergence of evolution demonstrates three parts of evolutionary theory working together: common ancestry, speciation, and natural selection. From the fossil record and our knowledge of continental shifts, scientists successfully predicted that we would find marsupial fossils in Antarctica. At the time of the marsupial invasion, South America joined Australia as a part of the supercontinent, Gondwana. In moving from South America, they crossed through Antarctica between 30 and 40 million years ago. Further confirming this theory, the marsupial fossils that the expeditionists found were between 35 and 40 million years old.