The theory of continental drift is a prime example of evolution in scientific thought. As recently as 30 years ago, geologists were taught that Werner's hypothesis that the continents as we know them today had evolved from one connected protocontinent was no more than a German's dream. Today it is accepted as the most plausible explanation of the Earth's evolution. For an explanation of the process behind continental drift, see the Tectonics section.
Starting from a giant landmass known as Pangea, which began to break up and drift apart nearly 200 million years before the present, the land has ridden on the Earth's molten interior and the continents have been carried to their present positions. As extraordinary as this seems, it is well supported by evidence from magnetic alignments along rifts in the ocean floor, and paleontological evidence that lifeforms all evovled from a common ancestor. In fact, the simplest and yet very valid evidence for this theory is that the continents on the whole look like the parts of a puzzle pulled apart.
The first map is a reconstruction of what geologists believe to be the ancient landmass of Pangea. The continents as they will develop are already clearly evident before drift begins.
The next map shows Pangea after 20 million years of drift has
split the continents along the line of the North Atlantic and
Indian Oceans. North America seperated from Africa, as did India
After another 45 million years of drifting, rifting is extending towards the split which will eventually seperate Greenland from North America.
65 Million years before the present the drifting continents have begun to assume their familiar alignment. South America has at last separated from Africa and the North Atlantic rift has dramatically widened.
In this present day map below, the arrows point in the direction of continued drifting. Where will the continents be 200 million years from today?