Mesozoic Life

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Mesozoic Life

• Chapter 15
• Part 2

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Meoszoic reptiles

• Turtles
• Crocodiles

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Mesozoic reptiles

• Two orders of dinos
• Saurischia
• Ornithischia
• Saurischia lizardlike pelvis
• Ornithischians birdlike pelvis

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Saurischian dinos

• Theropods
• Carnivorous
• Bipeds (two feet)

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Small theropod 2-3 kg

• Compsognathus
• Ate lizards

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Theropods

• Coelophysis

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Other theropods

• Velociraptors

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Other Theropods

• Deinonychus
• Means terrible claw

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Large theropod

• T-Rex
• 3-5 tons
• Not alive in Jurassic

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Theropods
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Saurischian dinos

• Sauropods giant, 4 footed, herbivores

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Sauropods

• Brachiosaurus
• 50 feet high
• 100 feet long
• 120,000 lbs
• Each neck vertebrae gt3 feet

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Sauropods

• Apatosaurus
• Formerly known as brontosaurus

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Sauropods

• Diplodocus

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Sauropods
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Ornithischian dinos

• Bird hipped
• 5 groups

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Ornithopods

• Duck-billed dinosaurs
• Herbivores

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Ceratopsia

• Horned dinos
• Triceratops

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Ceratopsia

• Horned dinos

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Stegosaurus

• 4 footed herbivore

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Ankylosaur

• Heavy armor
• 4 footed herbivores
• Tail is a club

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Other Mesozoic Marine Reptiles

• Ichthyosaurs
• Porpoise-like
• Ate fish, cephalopods
• Fully aquatic
• Gave birth to live young?

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Marine reptiles

• Plesiosaur
• Fish eater
• Flippers could move on land?

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Marine reptiles
Ichthyosaur

• Plesiosaur
• Fish eater
• Flippers could move on land?

Plesiosaur
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Marine reptiles

• Mosasaurs
• Related to Komodo dragons
• Up to 25 feet long

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Pterosaurs Flying reptiles

• Late Triassic
• 1st 2 foot wingspan
• Later Up to 40 foot wingspan

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Flying reptiles pterodactyl

• Pterosaurs
• Late Triassic
• 1st 2 foot wingspan
• Up to 40 foot wingspan

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Flying reptiles

• Pteranodon

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From reptiles to birds

• Similarities
• Both lay similar eggs
• Similar skeletons (jaws)
• Differences
• Birds have feathers, reptiles dont
• Birds dont resemble living reptiles
• Finding more dinosaur fossils with feathers

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Flying reptiles

• Archaeopteryx (Jurassic)
• Feathers and wishbone
• Similar to theropods
• Transition between birds and reptiles?

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New fossil finds

• 4 winged bird-dino transition
• Early Cretaceous
• Younger than archaeopteryx

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Gliders or fliers?

• From the ground up?
• Climb trees and glide to ground?
• New fossils thought to show gliding like flying
  squirrels

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Other reptiles

• Lizards are ancestors of snakes
• Lizards in Permian
• Snakes appear in Cretaceous

Leg bones?