Dinosaur Evolution. How do we know when dinosaurs lived? Layers of sedimentary rock & absolute...
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Transcript of Dinosaur Evolution. How do we know when dinosaurs lived? Layers of sedimentary rock & absolute...
Dinosaur Evolution
How do we know when dinosaurs lived?
• Layers of sedimentary rock & absolute dating–Late Triassic (during Mesozoic)
through end of the Cretaceous
–Also see birds & flowers for the first time during the Mesozoic (you know this!)
Dinosaurs?• “Terrible Lizards” (1841)
– Sir Richard Owen
• Not all reptiles are dinosaurs!• Dinosaurs did not fly or swim!
– Pterodactyls were flying lizards (or at least winged lizards)
Ornithischia
• 1887- bird hipped (posterior pubis along ischium)
• Ceratopsia (Triceratops), Thyreophora (Stegosaurus), Ornithopoda (Iguanodon, Hadrosaurs)–Some may have been bipedal
Saurischia
• Lizard pelvis–Pubis anterior & downward
• Up to 75,000 kg
(over 165,000 lbs!)
*Brachiosaurus probably had a blood pressure that exceeded 630mmHg (yours is probably around 120mmHg)
• Sauropoda- herbivores(Diplodocus )
• Therapoda (bipedal meat eaters) T. rex, Maniraptora (Velociraptor), Dilophasaurus
Good bye…
• Cretaceous-Tertiary Extinction (K/T Extinction)–Active plate movement, mountain-
building, volcanism
–Lowering of global sea level
–Gentle global cooling
–Asteroid impact
K/T Extinction
• Chicxulub (devil’s tail) crater- Gulf of Mexico–Block sunlight–Short-term global warming–Global wildfires–Acid rain–Long term global cooling