Age of the Dinosaurs

The more recent geological history since the Cambrian Explosion is divided into phases characterized by typical fossils in each phase. Transitions from one phase to the next were often triggered by geological catastrophes. The most significant of these catastrophes marked the transition from the age of arthropods (invertebrates) to vertebrates.

Initially, dinosaurs were considered to be cold-blooded, sluggish, and unintelligent creatures, thought to be simple ancestors of today’s vertebrates. However, numerous studies since the 1970s have shown that dinosaurs were active animals with elevated metabolic rates and complex social interactions. If not for another catastrophe (see Station 10), they might have continued to dominate the animal world. It is possible that even an intelligent form of dinosaur might have evolved.