Why is Pangea important? Why are cast fossils important? Why are geological surveys performed? Why are physical maps important? Why is it important to study geology? Why is the theory of plate tectonics important? Why do few fossils exist from the Precambrian?
This trend, however, did not last forever. After themass extinctionof dinosaurs some 201 million years ago, they eventually would return to spread to these once hostile regions. "After that, they were global," Irmis said. "The (mass extinction event) opened up a lot of ecological space," ...