The Mesozoic Era is the era between the Paleozoic and Cenozoic Eras, comprising the Triassic, Jurassic, and Cretaceous Periods. The Mesozoic Era is commonly referred to as the Age of Reptiles. Highlights of the Mesozoic Era include:
• Dominant large animals: Reptiles and dinosaurs; birds and mammals appear.
• Increased mountain building occurred in many regions around the globe, and with that, lots of sediments were generated from erosion.
• The ancient supercontinent, Pangaea, begins to breakup at about 200 million years ago (Pangaea is discussed in Chapter 4).
• With the breakup of Pangaea, continents began moving apart. This caused isolation of species and communities, and as a result, created more diversity in plant and animal species through divergent evolution.
• The ancestral Rocky Mountains and Cordilleran Ranges formed in western North America between about 120 to 66 million years ago.