you look at a world atlas, some of the continents seem to fit together like a jigsaw puzzle. Some scientists believe that the Earth's continents were once joined to form one supercontinent called Pangaea, which means 'all lands' in Greek. More than 200 million years ago, the tectonic plates began to shift, causing the land mass to split. This drift caused plants and animals on each continent to evolve according to their own environments.

In the early 20th century, scientists found identical fossil species along the once-interlocking eastern coastline of South America and the western coastline of Africa. But the species had adapted differently on each continent.

Australia's wombat is a marsupial, which means its young complete their development in a pouch. The wombat shares a common ancestor with the North American groundhog. However, the groundhog is a placental mammal, which means it is fully developed upon leaving the female's womb. The two animals developed differently based on adaptations to their individual environments.

Land masses that broke into islands have a unique biological diversity. One example is Madagascar, a hot spot of biodiversity. This island off the southeastern coast of Africa and its smaller, neighbouring islands have eight plant, four bird and five primate families that are endemic, which means they aren't found anywhere else in the world. For instance, 142 of the 144 amphibians in Madagascar are endemic.