What effect on the evolution of mammals was caused when the continents drifted apart?

The answer is similar ecological opportunities on different continents have produced some striking examples of convergent evolution.

When the Pangea continent broke apart, different continents bore varying climates hence species adapted to their environment. Convergent evolution occurred when different species gained similar anatomical features that are resourceful in the environment (continent) in which they are living. An example of convergent evolution is exhibited in bats that are mammals but have features analogous to those of birds such as wings.

There has been comparable ecological opportunities on various continents have created some astonishing examples of convergent evolution

The self - sufficient evolution of identical features in species of different lineages is called Convergent evolution. This makes analogous design that have related function or form but were not existent in the last typical ancestor of those class.