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Mesozoic Era. Age of Reptiles. After Permian Extinction Millions of years pass before diversity of living things begins to rise again. Ammonites evolved Related to squid Many types evolved Became extinct after f ew million years
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Mesozoic Era Age of Reptiles
After Permian Extinction • Millions of years pass before diversity of living things begins to rise again. • Ammonites evolved • Related to squid • Many types evolved • Became extinct after • few million years • Index Fossil –they were used to date sedimentary rock layers from different periods of the Mesozoic
Triassic Period • Pangaea- Large landmass • Many Reptiles evolved • 1stmammals appeared
Triassic Earth • Pangaea –supercontinent • Hot summers, cold winters • Began to separate toward end of Triassic • Panthalassa- “all sea”
Triassic Life • Dinosaurs • Other reptiles • Mammals-warm blooded animals that nourish their young with milk. • Small, rodent-like • Plants- gymnosperms-group of plants with seeds that lack a protective outer coat. • Cycads & Ginkgoes
Jurassic Period • Pangaea continued to split apart • Dinosaurs evolved and became widespread
Jurassic Earth • Mountain building occurs as plates move • Jurassic Sea forms • Jurassic Sea helps moderate climates • Climates were mild (WARM) at all latitudes. • Warmer climates helped contribute to development of new life forms
Jurassic Life • Fish w/ modern characteristics evolved (jaws, scales, skeletons, & fins) • Reptiles adapted to oceans • Dinosaurs thrived and evolved • Meat-eating dinosaurs evolved
Jurassic Birds • Pterosaurs evolved • Had wings formed from membranes (some with claws) • Reptile-like teeth • Feathers • Glide not “fly”
Cretaceous Period • Diversity of life • Dinosaurs • Birds • Flowering plants • Small mammals
Cretaceous Earth • Pangaea continued to split • Shallow seas and great swamps formed • Formed the coal deposits of the US & Canada
Cretaceous Life • Large, slow moving plant eaters (move on 4 legs) • Smaller, faster meat eaters (move on 2 legs) • Snakes evolved • Small mammals flourished
Plants • Flowering plants called angiosperms • Angiosperms- plants that produce flowers and seeds with an outer covering • Trees: willow, birch, sassafras
Cretaceous Extinction • Most scientists think a large meteorite collided w/ Earth causing mass extinction • Dust blocked sun for years causing plants to die (no photosynthesis w/o sun) • Caused plant eating dinos to die which caused meat eating dinos to die • Some small birds, mammals, and reptiles survived
Cretaceous Extinction (cont.) • Evidence of large meteorite impact on Yucatan Peninsula • thin layer of sediment of Iridium (rare on earth, but in meteorites) • Other scientists believe volcanic eruption in India let to climate change • Several factors probably contributed to the mass extinction