Unit 4 Dinosaurs Lecture 1 Definitions The History of the Field Paleontologists Paleobiology behavior ecology functional anatomy people who study ancient organisms the study of the lives of ancient organisms physiology 1 First writing about dinos came out of china They called them dragon bones Dragon Bones from long dead serpents were unearthed for centuries for medical purposes in China they would dig them up turn them into powder and sell them as a Viagra 2 In 1671 Giant Human bone found in Europe They believed it was a scrotum of a giant human became known as Scrotum humanum First dino to be named Turned out to be a real dino and not a Giant human 3 In 1770 a 40ft long sea monster named Mosasaurus was found in Holland 4 In 1824 Megalosaurus big lizard was discovered but no one paid attention because they thought they were just over sized lizards 5 Around the same time giant teeth were also found Again just thought it was a big lizard Finally once they named it Iguanodon it got a huge amount attention because it was a plant eating lizard 6 The first dinos were depicted as giant versions of currently living lizard species 7 Richard Owen noted these bones were different than current reptiles In 1842 he designated them as a new group of reptiles Dinosauria Fearfully Great Reptiles Again before he did this people just believed these bones were just giant lizards that were living at the time a Owen made several mistakes they made all dinos walk on four legs What Makes a Dina a Dina Have teeth in sockets like crocodiles Pterosaurs flying reptiles and Dinomorphs Pterosaurs and Dinosauromorphs had metatarsal ankles could stand up right Unique Features Three or more sacral vertebrae fused backbones in hip region Hands with three main fingers Perforate acetabula hole where the thigh bone attached goes all the way through the hip By the late 1800a there was enough evidence to realize there were two types of dinosaurs 1 Ornithischians w hips shaped like birds 2 Saursichians w hips shaped like lizards Dinosaur Renaissance Robert Bakker In 1964 Dinosaur Renaissance occurred thanks to the Deinonychus real raptor from Jurassic Park It changed the view on dinos all dinosaurs were athletic and probably more like the birds we have living today People became really interested and everyone began to study them to prove him wrong It turned out that Bakker was partially right into dinosaurs a way to organize physical features also caused people to look Cladistics Lecture 2 The Age of Dinosaurs Lived 238 million year until 65 5 million years ago during what is called the Mesozoic Era or the Age of Dinosaurs Age of dinos broken into three periods Triassic Jurassic Cretaceous How do we know the ages Observe the rocks o For dinosaurs are sediments Uranium 235 is the best It is formed in the Earth It breaks down over time after 704 million years it will break down by about 50 half life Carbon dating has too short of a half life to be of use for dinos Climate we know from the kinds of plants animals and temperature sensitive isotopes that World was warmer Arid in equatorial regions Continents moved driven by volcanic sea floor spreading Plate tectonics Like Florida in middle latitudes Triassic Era Pangea Continents adjoined Cretaceous Era Dino distributions have helped to figure out where the continents were and explain their distribution With warmer Earth there was no ice at the poles oceans were higher seaways crossed the continents warm shallow sea this influenced where and how dinosaurs traveled dinosaurs had less land to live on compared to today Vegetation Triassic Jurassic plants large giant trees not much to forage on ginkos pine trees cycads in dry areas conifers less ground cover no grass Trees had great height and chemical defenses and poor ability to regenerate By the middle of the Cretaceous Period flowering plants angiosperms finally show up ground cover These plants regenerate quickly to survive foraging Dinosaur relatives Crocodilians and their close relatives first were terrestrial land dwellers some where even bipedal some were fully aquatic sea monsters some were just like today s crocodiles Deinosuchus growth grew at rates like living alligators very unlike the dinosaur pattern Looked at growth plates these animals just kept growing slowly and became gigantic Supercroc Sacrosuchus 40ft from Africa had to figure out the bite force they used a bite force meter to measure the American crocodiles and then used that and scaled it up to meet the supercroc saltwater crocodile 3 700lbs highest bite force ever measured Calculated that supercroc and the Deinosuchus 31 00lbs Lots of sea monsters Ichthyosaurs were dolphin like retiles We know their fin profile from impressions Long Necked Plesiosaurs the Loch Ness Monster the loch only about 10 000 years ago so it would have had to have gotten in fairly recently Mosasuars aquatic animals closely related to today s monitor lizard The real giants were the Quetalcoatalids w 35 40 ft wingspans They were always found well inland and are thought to have been dinosaur scavengers Mammals appear at the same time as dinosaurs mostly rat or possum sixed throughout the Age of Dinosaurs In the late Jurassic birds show up Vegavis duck found in Antarctica this leads to believe there were also chickens present Fossils are remains of ancient life for dinosaurs we tend to think just bones but that isn t the case Trace Fossils not actual physical remains Trace Fossils tracks eggs skin impressions stomach stones bite marks coprolites dino poop Skin impressions reveal aspects of thermoregulation display features Gastroloths gizzard stones how they break down food Eggs nest reveal aspects of ovaries behavior in laying size of young etc Bite marks who ate who damage they could produce biting force Coprolies dino dung tells what they ate if they have strong digestive acids how much dentition broke down items Where do we find dinosaurs Rocks sedimentary rocks composed of consolidated sediments from rivers or desert Often once buried minerals precipitate through the pores in the bones and harden them making them more resistant The original mineral salts of bone however are usually still there Generally this take about 10 000 years Badlands places where plants don t grow well best place b c lots of sediments are exposed Sometimes we find them in marine sediments that were near the shore where they were washed out to sea Are dinos in Florida No we were under the sea for most
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