Dinosaur Review Session Kids are fascinated by dinosaurs because they re super cool and actually real Paleontologist someone who studies any aspect of ancient organisms Paleobiology the study of the lives of ancient organisms First accounts of dinosaurs were written in China calling them dragon bones then the Europeans then scrotum humanum but really the end of a leg bone Cuvier figured out that things could go extinct explained with the sea monster Mosasaurus Megalosaurus was the first valid dinosaur People didn t get excited about it though because it sounded like just another big reptile from Australia and Africa Iguanodon teeth like iguana people got excited because it was a giant plant eater Early renditions of dinosaurs were just bigger versions of modern day lizards Richard Owen recognized dinosaurs as a unique group of animals In 1842 he named them fearfully great reptiles or dinosauria Crocodiles and pterosaurs especially pterosaurs are closely related to dinosaurs Unique features of dinosaurs 3 sacral vertebrae 3 fingers Perforated acetabulum hole in the pelvic bone Tell dinosaurs apart by hip structure Ornithischians bird hip Saurischians lizard hip Dinosaur renaissance in 60s Deinonychus was described as athletic like birds First time they weren t thought of as like modern reptiles More like a bird not sluggish Discovered by Robert Bakker People got excited about dinosaurs Dinosaurs lived 238 65 54 million years ago We know these ages because of isotopes and uranium 235 dating this turns into lead Climate Lot warmer arid The middle was like Florida Poles were like Seattle The continents moved with plate tectonics and Pangaea was pulled apart to today s configuration All dinosaurs are terrestrial land animals Crocodiles are relatives and were living at that time Ike 40 ft 3 700 lb is the highest bite force saltwater crocodile used to help estimate other bite forces Lots of sea monsters Plesiosaurus like the Loch Ness monster more like a lizard then a dinosaur Mammals appear at the same time as dinosaurs but are more rat like Fossils are evidence of ancient life Trace fossils are good for biology Not actual physical remains Like eggs impressions tracks etc Tracks told us that they didn t drag their tail posture Where do you find dinosaurs In Sedimentary rocks From rivers or desert wind storms Rarely found in igneous volcano or metaphoric mountains rocks Can see the fossils eroding out of the land usually Bad Lands and start digging Not just digging at random No sediment leftover in Florida Have to go to Chattahoochee River in Georgia Ornithischains Pubis towards tail And beaks to crop plants First dinosaurs started small all dinosaurs every group Thyreophora shield bearers or armored dinosaur Osteoderms were pieces of bones found in skin like in alligators Stegosaurus Endocasts sediment filing in the brain cavities show the brain capacity not much for the stegosaurus Crazy theories in the history of dinosaur discovery because the field came from geology who didn t have a lot of biology background Cerapoda have a gap between front and back teeth Heterodontosaur different tooth lizard teeth situation like a mammal We don t know the sex of any dinosaur We do know the color of one dinosaur We do know of sexual dimorphism differences in size and shape between sexes No credible evidence that they were in the seas or trees Hadrosaurs duck billed Tooth batteries hundreds of interlocking teeth Self sharpening enamel on one side and self sharpen Know more about duck billed than any other dinosaur because of just the number of fossils These things are just everywhere 2 kinds of duckbills with and without crests Crazy theories about aquatic functions of crests it can t be a snorkel Marginocephalia Have a rim of bone protruding from the back of their skulls over the neck Theories about bone heads head butting Or flank butting Finite element modeling computer rendition to see the mechanics of how it would work in theory show it s probably for head butting Ceratopsians horned dinosaurs Parrot like beak Big neck frills for the neoceratops Protoceratops They thought the oviraptor was stealing its eggs but it s an oviraptor egg Good mom not common in reptiles No offense reptiles Pachyrhinosaurus Thought the boss was possibly for shoving and is known as the largest horn Saurischians lizard hips Pubis points forward Long neck Leaf shaped teeth Sauropods earth shakers Look at skull and look for the nostrils on top of its head Supersaurus and seismosaurus Can t fit this dinosaur in this auditorium Like 140 feet Fits in the building but not the room Apatosaurus or brontosaurus Named twice over splitting Tallest dinosaur is sauropseidon and is 56 feet tall doesn t fit in this room People thought the sauropods had trunks on the top of their head like tapirs to deal with the nostril on the top of the head ordeal Theropods Carnivorous and thin hollow bones like birds to increase speed Ceratosaur Gap in front and back teeth Coelophysis Found meals inside stomachs Really the remains of crocodiles not cannibalistic Spinosaurus The only skeleton found was blown up in WWII by the British Ornithomimids fastest Bird mimic dinosaurs Tyrannosaurus 2 finger Segnosaurs Edward Scissorhands plant eating theropods only plant eating theropod known Oviraptors theropod not really an egg stealer Deinonychosaurs had big claw on second toe Troodontids were the smartest dinosaurs Encephalization quotient shows brain size relative to body mass Comparable to birds Dinosaurid if raptors survived until today Freaky as hell T Rex First mount had tail on ground and too many fingers not good They teeter Have a great sense of smell endocast shows big olfactory bulbs Can t run but amble cant suspend in air during motion Like elephant Cannibal Evidence for it being both a scavenger and a predator but unsure which was more often Bones show that their metabolism was a blend between reptiles and mammals Really changed the perception of their physiology Grew like marsupials slow growing mammals Kinda in the middle Disappeared 65 5 million years ago 40 80 of life died at that time The three theories are Volcanoes changed the climate Seaways drained Asteroid in Yucatan peninsula gulf of Mexico Why did some animals survive mammals reptiles birds amphibians Main theories don t give a good explanation for that Archaeopteryx first bird Birds lived with dinosaurs Birds are dinosaurs first argued by Huxley Lots of features in common
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