How did Pangaea affect life?
In general, when continents come together species diversity tends to go down and when big continents start to break up, species diversity tends to increase.
When there are land bridges or connections between continents, organisms tend to wander around looking for new habitats. This tends to produce fewer species. But when there is more islands or separate land masses, this tends to produce more specialized species adapted to these unique environments.
For example, a recent study suggest that T-rex may have crossed a land bridge at one time in the Cretaceous and become "an invasive species". This may have also give rise to a number of new t-rex type species