What is the theory of Continental Drift and what evidence is there to support it?

Continental Drift is a theory credited to Alfred Wegner in the early 1900s. This theory implies that the continents were once joined in one supercontinent called Pangaea and have since drifted apart. The movement of the continents is ultimately caused by convection currents within the mantle. These convection currents force the overriding tectonic plates (which includes the continents) to migrate very slowly through time. The primary evidence for continental drift is the fit of the continents. Just like a jigsaw, the shape of the continents complement each other suggesting that at one point in time they were connected. Furthermore, fossil evidence from the east coast of South America and west coast of Africa record the same species living on these two continents 200 million years ago, these species were incapable of swimming across an ocean the size of the Atlantic so the two continents must have been connected. Further stratigraphic and geological similarities also provide evidence that South America and Africa were connected in the past.