The borders (coastlines) of the continents underwent a number of changes
since the split. Often, chunks of land were washed away with water,
slowly or in bigger portions. The coast was generally "smoothed" by the
ocean currents too, and in some places more land was added with the
material that the ocean currents brought.
Then, the tectonic plates continue to move, so this adds to the changes of the shape of the continents.
Energy is always lost as energy is moved from one level to another. ... The loss of energy due to the second law of thermodynamics results in a pyramid with a large base and a 10% ratio between levels.
