Chapter 1 An Introduction to Terrible Lizards and the Science of Dinosaur Paleontology Paleontologist someone who studies ancient organisms Paleobiology the study of ancient life Scrotum humanum the first proper scientific name given to a dinosaur Thomas Jefferson was a fossil fanatic Mosasaurus 40 foot long seagoing relative of today s monitor lizards such as Komodo dragon o Baron George Cuvier studied giant sloth fossils from South America examined the o specimen and theorized they died out long ago Cuvier was a very influential man and was considered a genius people for the first time gave serious consideration to the possibility that animals can and have gone extinct Reverend William Buckland credited with describing first scientifically valid dinosaur o Megalosaurus big reptile Gideon Mantell found the teeth and bones of an animal o o Iguanodon iguana tooth The first described herbivorous dinosaur Sir Richard Owen concluded in 1842 that dinosaurs were a unique and formerly unrecognized reptilian group instead of giant reptiles Reptiles are scaly skinned terrestrialized animals that lay hard shelled eggs o o Named them Dinosauria fearfully great reptiles Dinosaurs are Archosaurian reptiles which includes the crocodilians and pterosaurs extinct flying reptiles and dinosauromorphs extinct dinosaur like reptiles o Characterized by teeth in sockets that are replaced throughout life one way know Crocs Allig are closely related to Dinos Pterosaurs and dinosauromorphs collectively called Avemetatarsalians are the closest relatives of dinos because they have hinge like ankles where the pivot is in the middle of the cluster of bones that make up the ankle Among the Avemetatarsalians the dinosauromorphs are the closest relatives to the dinos because they have erect posture due to an inturned ball on the femur thigh bone Dinosaur s unique key features Three or more sacral vertebrae fused backbones o o Hands with three main fingers two in tyrannosaurs one in alvarezarids o Perforate acetabulae hole where thighbone attached goes all the way through the hip Two major groupings of dinosaurs o Ornithischians with pelvic bones in the shape of bird hips o Saurischians with pelves like lizards lizard hips Fossil feud of the 1870s 90s between Othniel Charles Marsh and Edward Drinker Cope found and named some of the most famous dinos but most of their descriptions are considered invalid today Louis Dollo was the first person that we can call a dinosaur paleobiologist since he was interested in the lives of dinos their ecosystems etc Deinonychus terrible claw a velociraptor o Robert Bakker shared the story of this dino and interest in dinosaur research soared Chapter 2 The Age of Dinosaurs First dinosaurs appeared on fossil record 238 MYA during the Mesozoic Era Referred to as the Age of Dinosaurs since they were the dominant animals Three major divisions to the Mesozoic Era First period is the Triassic Period 251 200 MYA The oldest dinosaurs show up midway through this period Second period is the Jurassic Period 200 146 MYA The time of the largest dinosaurs Third period is the Cretaceous Period 146 65 54 MYA Dinosaurs went extinct at the end of this period Best isotope for dating rocks is Uranium 235 which breaks down into Lead 207 Half life the amount of time it takes for half of the original material to break down accuracy is within the range of several million years Climate was arid in equatorial regions and similar to Florida in middle latitudes Closer to the poles it was cool wet and rainy o No ice caps at the poles o More free water in oceans o Greater portion of the continents covered by water During Triassic Period plates of earth were adjoined into the super continent Pangea The continental movements are driven by volcanic seafloor spreading in the oceans Plate Tectonics Gymnosperms pine trees ginkgo trees dominated the world s dryer ecosystems o Great height chemical defenses thick bark tough foliage o There was less ground cover than there is today Angiosperms flowering plants showed up midway through the Cretaceous Period o World became more vegetated with ground cover and closed forests with deciduous trees became abundant All dinosaurs were terrestrial animals Crocodile relatives during the age of dinosaurs were small agile terrestrial predators o Deinosuchus terror crocodile bony armor of the animals extended the length of their rapid growth phase puberty for an extra 20 years Present day saltwater croc 3 700 lbs bite vs 31 000 lbs giant extinct Deinosuchus First turtles from Triassic Period fully terrestrial and had teeth Ichthyosaurs reptiles that looked and swam like dolphins Some were 40 ft long deep diving ones had eyes 1 ft in diameter Plesiosaurs long necked supposed Loch Ness Monster Bodies like sea turtles necks long and snake like with up to 80 90 vertebrae Mosasaurs sea going relative of monitor lizards like the Komodo dragon Some were 50 ft long and swam like crocodilians Pterosaurs close relatives of dinosaurs with bat like wings and fully covered with fur First powered flyers Largest known was Quetzaloatalus with 36 ft wingspan Thought to have scavenged dead dinosaurs using toothless beaks Mammals appeared about the same time as the dinosaurs in the Late Triassic Period They were initially rat like and mouse to opossum sized and remained so for the 173 million year tenure of the dinosaurs Fossils are evidence of ancient life Trace fossils primary means by which paleontologists learn about dinosaur biology traces of ancient life eggs skin impressions bite marks o o o o o o o o o o o To be fossilized remains of the animal must be rapidly buried under sediments from rivers most common windblown sand fairly common or volcanic ash rare Sedimentary rock rocks formed from sediments Igneous rock from volcanos Metamorphic rock sedimentary or igneous rocks that have been deformed by pressures of earth o Rarely has good dinosaur remains Fossil dinosaur bones usually composed of the original calcium phosphates hard mineral in bones Animals are rarely fossilized Most dinosaurs are known from a single partially complete specimen Badlands where the majority of dinosaurs are found today with exposed rocks with little vegetation Chapter 3 The Ornithischia Plated Dummies and Walking Tanks First Ornithischians that appeared in the Middle Triassic Period were small bipedal Attributes of Ornithischia Bird shaped hips Beak to crop plants Nutcracker jaw joint o o o o Thyreophora armored
View Full Document
Unlocking...