4/3/2013Why the fascination?Learning that dinosaurs are “real” is exhilaratingThis often leads to early occupational goals whereby one inspires to become a:Paleontologist: someone who studies any aspect of ancient organismsClicker Question: I want to know how many of you were interested in dinosaurs as kids?A. Yes, interestedB. No, never had an interestThis course is specifically about Paleobiology: the study of the lives of ancient organisms (physiology, behavior, ecology, etc.)The History of the FieldIt is hard to miss dinosaur bones.Clearly people knew about them before their scientific recognition in 1824China“Dragon bones” from long dead serpents that were used for medicinal purposesEngland1676 Giant “human” thigh bone was foundLater reinterpreted as the Giant’s private partsThe specimen was name Scrotum Humanum, which we know now to be the end of a dinosaurs thigh boneThomas JeffersonSent Lewis and Clark out to explore the Louisiana Purchase to find mastodoms- furry elephants1770A 40 foot long monster named Mosasaurus was found in HollandThe first time the word extinct was used1824William Buckland found a reptile jaw with pointed, serrated teeth from EnglandHe called it MegalosaurusIguanodonThis caused a huge sensatin because giant herbivore reptiles were not heard of.Note: reptiles like lizards and crocodilesHave scaly skinLay hard shell eggs on landScrawl on 4 legsRichard OwenIn 1842, designated them as a new group of reptiles: The Dinosauria meaning “Fearfully Great Reptiles”Dino-mania began and hundreds of thousands of people came to see the dinosaurs.So what makes a dinosaur a dinosaur?Scrawl on 4 legs three or more sacral vertebrae= fusedHands with three main fingersPerforate acetabulae (the hole where the thighbone attaches goes all the way through the hip)Yankee DinosaursThe first documented remains were tracks found in 1800Written off as being from giant birds1858Joseph Leidy was given a nearly complete skeleton of a duck-billed dinosaurDinosaurs were bipedal!Now began to be compared to kangaroosWhen it came to mounting the skeleton, they figured that the dinosaurs would drag its tail just like other reptiles… they had to break the tail to give it the assumed lookTwo typesOrnithischians with hips shaped like birdsSaursichians with hips shaped like reptiles“Fossil Feud”The late 1800sLed to the discovery of some of the most famous dinosaurs from the North American westMarsh vs CopeUnited States MuseumsCarnegieSmithsonianAmerican MuseumFunded by rich backers ( still happens today)After WWII most dinosaur hunting slowed downIt was considered kid stuffMost dinosaurs were thought to have been foundDinosaurs were only to get the public to come through the gates so scientists could pay for their important work on mammals and birdsThe Dinosaur RenaissanceDeinonychus (the raptor from Jurassic Park)Robert BakkerSaid all dinosaurs were athletic and more like living birds and animalsHe pointed to their athletic builds and their bone microstructureThe OutcomeEveryone started studying and hundreds of jobs were createdA new dinosaur is being named every weekBakker was partially rightOther events that have fueled the RenaissanceIt was proposed that a giant asteroid hit the Earth and wiped out all the dinosaursCladistics: a method to organize physical characteristics of dinosaurs and discern relationships came into common use4/5/13When did dinosaurs live?238 million years until 65.5 million years agoHow do we know these ages?Radioactive isotopes in volcanic rocks formed at the time of the dinosaurs decay into secondary materials know as ratesUranium 235 breaks down over timeAfter 704 million years only 50% of the original Uranium remains. This amount of time is called a half-life.ClimateIt was a lot warmer in the Age of DinosaursIt was arid in equatorial regionsPlate TectonicsContinents move via seafloor spreadingIn the Triassic continents were adjoined- called PangeaBy the end of the Cretaceous they were close to present positionsDinosaur distributions have helped to figure out where the continents were and explains their distributionsFor example fossils of late Jurassic North America dinosaurs are also found in AfricaWith a Warmer Earth there was no ice at the polesOcean levels were higher and covered much of the continents and ironically dinosaurs had less land to live on than there is todaySeaways crossed the continents and influences where dinosaurs can travelMountain SystemsThe world used to be fairly flat compared to todayThe FloraThe types of plants available for forage had a large influence on were dinosaurs can liveTriassic and Jurassic PlantsThere was less ground to cover back then since there was no grass. Trees had great height and chemical defenses and poor ability to regeneratePteridiophytes in wet aresCycads in dryer areasPine trees, conifers, and ginkos were dry area treesCretaceous Period flowering plantsThese plants regenerated quickly- can survive grazing.The first known grass appearedWho lived with the Dinosaurs?For the most part, dinosaurs are terrestrial (live on land)CrocodiliansFirst ones were terrestrial, land dwellersSome were even bipedalSome were fully aquatic sea monstersSome were just like todays crocodilesThey could be up to 40ftConsidered to be dinosaur killersDeinosuchus growth(The giant crocodile)Grew at rates like living alligators, very unlike the dinosaur pattern.Kept growing slowly over many years.What was the Supercroc’s biting force?Saltwater crocodile has 3,700 lbs of bite force = highest bite force ever measuredSupercroc and Deinosuchus = 31,000 lbsTurtlesMost were like today’s turtles but reached giant sizesIcthyosaurs look like dolphins but are related to lizards… engage in live birthLong- Necked PlesiosaursThe supposed “Loch Ness Monster”MosasaursAquatic animals closely related to komodo dragonXiphaxtinus audax—a 17 foot tarpon.In the air were pterosaurusFirst ones had long tails, some were filter feeders, some have been found with furRussians found a specimen with fur on itThe giants were the Quetalcoatalids with 35-40 foot wingspanThey are always found well inland and are thought to be dinosaur scavengersMammals appear at the same time as dinosaursMostly Rat or Possum sized- throughout the Age of DinosaursPossums have remained almost unchangedIn the late Jurassic birds show upVegavis is a duck that was found in AntarcticaFrom this finding scientists think that there must have been chickens around
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