The Mesozoic Era

• The Mesozoic Era lasted from 248 mya – 65 mya

Major Events of the Mesozoic Era1. Pangaea broke apart

2. Formation of the Rocky Mountains• During the break up of Pangaea the Pacific Plate

subducted under the North American Plate

2. Land plants adapted to drier climates ex: gymnosperms and angiosperms

3. Reptiles evolved because they could adapt to drier climates since they lay their eggs on land

• The Age of Reptiles! During this era, reptiles dominate and the specific type of reptile that dominates is known as the DINOSAUR

Types of DinosaursCarnivores – meat eaters like the Tyrannosaurus rex

Types of DinosaursHerbivores – plant eaters like Apatosaurus

3. Some dinosaurs were small like Dromaeosaurs

4. Some dinosaurs evolved to fly like Pterosaurs

5. Some dinosaurs evolved back into the water like Ichthyosaurus

The End of the Mesozoic• Another mass extinction occurred from meteorite

impact at Yucatan Peninsula in Mexico– This caused lots of dust, enough to block the sun which caused plants to die– Without many plants to eat herbivores die– Without animals to eat carnivores die

K-T Extinction• 50-60% of all life became extinct at the end of the Cretaceous Era.

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What Animals did survive the Meteorite Impact?• Smaller reptiles like the ancestors of our turtles,

snakes, crocodiles, and lizards• Small mammals

K-T Boundary• Thin, whitish line in

the rock• Lots of dinosaur fossils

were BELOW the line; and no dinosaur fossils were ABOVE the line

• About 65 MYA …

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