Mass extinction 232 mn yrs ago led to dinosaurs' rise: Study
A mass extinction event 232 million years ago triggered the expansion of dinosaurs, scientists have said, based on discovery of several dinosaur footprints in Italy's Dolomites mountains dating back to that period. Scientists linked the extinction event to climatic shifts from dry to humid and back to dry again, which also paved the way for lizards, crocodiles, turtles, and mammals.