Transcript Turiasaurus
Today – 1/18 • • • • Critter in the news / weather report Reading background End of the dinosaurs (?) First writing assignment Possible test question Peter Ward and Roger Smith in Gorgon want: A. To learn how mammals survived the endPermian extinction event B. Evidence of dinosaur ancestors C. To determine if the Permo-Triassic extinction was sudden or gradual D. All of the above Administration: “Get to know you” form worth 2 pts XC Ross’ OH in Gould-Simpson 205 Turiasaurus End of the Jurassic, 145 Ma 100+ feet long! Almost 100,000 lbs! sauropod - member of clade Sauropoda Other super-giants like Brachiosaurus and Seismosaurus more closely related to each other than to Turiasaurus Last time: Biostratigraphy – Principle of faunal succession Mammal-like reptiles of the late Permian* Mass extinctions http://darkwing.uoregon.edu/~millerm/meander.html Meandering river Braided streams /www.uky.edu/AS/Geology/howell Meandering v. braided stream: Braided streams: networks of interconnected channels that form where there is a large sediment supply, large fluctuations in flow levels, erodable banks Meandering river: think of large single channel slowly winding its way across a gently sloping plain. E.g. Mississippi R. Banks stabilized by well-established vegetation Carbon atom Carbon Isotopes All carbon atoms have 6 protons 98.9 % of carbon atoms have 6 neutrons, called C-12 1.1 % have 7 neutrons, called C-13 Plants prefer C-12 Scientists measure ratio in rocks, try to explain observations Stable isotopes, not radioactive like C-14 Features of the P-T carbon isotopic excursion Ubiquitous – global, all kinds of rocks including limestone, paleosol nodules, kerogen, and vertebrate teeth! Means that something big happened and that this can be used to find the boundary anywhere rocks deposited across the right time span are exposed So fast and so extreme that it cannot be explained by volcanism or other “normal” processes www.kent.ac.uk/physical-sciences USGS Methane hydrate mechanism: Enormous amounts of natural gas are stored in solid H2O (ice – but not quite the ice we are used to) cages at the bottom of the sea and under permafrost. This methane is enriched in C-12! Methane is a powerful greenhouse gas so release of some would initiate warming, perhaps starting a positive feedback Proposed causes of dinosaur extinction Out-competed by smarter, egg-eating mammals Disease Falling sea level Volcanically driven climate change Asteroid strike! (had been written off by 1980 because no crater had been found) www.physast.uga.edu/~jss/ 1980 - Walter and Luis Alvarez discover iridium rich clay layer www.geology.ucdavis.edu/~cowen/HistoryofLife/ktbits.gif http://www.lpl.arizona.edu/SIC/ Location of the Chicxulub crater - site of the K-T impact! Chicxulub - “tail of the devil” www.windows.ucar.edu/earth/images/chicxulb.gif Animation of Chicxulub crater formation Evidence for K-T impact World-wide clay layer with iridium, shocked quartz, spherules, and carbon 65 Ma tsunami deposits ringing the Caribbean Chicxulub crater It was a BIG explosion! Asteroid or comet was 10 km (6 mi) across Moving at 75,000 km/hr (45,000 mi/hr) 5 billion times the energy of Hiroshima World-wide forest fires, tsunamis, acid-rain, year-long “nuclear winter” At least 75% of all species went extinct, including 90% of all plankton http://www.lpl.arizona.edu/impacteffects/ Asteroid 1950-DA, March 16, 2880 Unlike the K-T impact that killed the dinos, the cause of the P-T extinction is still the subject of vigorous debate! Tethys Pangea Sea X http://jan.ucc.nau.edu/~rcb7/ The blue planet, 260 Ma http://dsc.discovery.com Siberian Traps Proposed causes of P-T extinction: Final assembly of Pangea – changes ocean currents, climate Volcanism – Siberian traps flood basalt, Chinese explosive volcanism. Release CO2, causes warming, promotes ocean anoxia by weakening currents, lowering O2 solubility, and melting gas hydrates. Impact Combination Insert pic of AC Petrified tree? AC shot from above! With inset of teeth What fossils tell us about dinosaurs How they looked - size, shape, skin How they behaved - diet, locomotion, social life, as parents Physiology - thermal regulation, growth patterns History of life - speciation and extinction, relationships among groups Environmental reconstruction, rock ages geochemistry, paleogeography, interaction between physical and biological worlds ← Griffin inspired by Protoceratops? ↓ web.ukonline.co.uk/conker/ www.dinoland.dk www.oum.ox.ac.uk/geolcoll.htm 1677 – Robert Plot publishes first known description of a dinosaur bone. However, he mistakes it for the femur of a giant human! www.lhl.lib.mo.us/events_exhib/exhibit/ex_paper_dino.shtml 1815 – William Buckland finds Megalosaurus jaw 1831 home.uchicago.edu/~shburch/dinopaper.html 1830’s – Meet Meg, plus the happy water lizard 1833 1836 – Gideon Mantell discovers the teeth of Iguanodon www.lhl.lib.mo.us/events_exhib/exhibit/ex_paper_dino.shtml Iguanodon – notice the sprawling legs 1842 – Richard Owen defines the “Dinosauria”, which translates as “terrible lizards” Depiction by Owen circa 1850 Benjamin Waterhouse Hawkins’ 1853 dinosaur reconstructions being prepared for display in the Crystal Palace, Hyde Park, London http://www.ric.edu/rpotter/cryspal.html www.simondevlin.com www.owen.k12.ky.us/trt/beverly/Megalosaurus_files/frame.htm http://www.healthstones.com/dinosaurdata/dinodata.html Nicholas Steno – “Father of stratigraphy” Second half of the 1600’s Said fossils were remains of organisms Principle of Original Horizontality – rock layers laid down horizontally, any deviation from this due to later disturbance Law of Superposition – lower layers are older, upper layers are more recent Early 1800’s geology comes alive! 1795 – Theory of the Earth by James Hutton: how rock layers form, hot inside, old, uniformitarianism, natural selection 1815 – Geologic map by William Smith: biostratigraphy 1830-1833 – Principles of Geology by Charles Lyell: stratigraphy 1859: On the Origin of Species by Darwin Archaeopteryx – London specimen, found 1861 Taphonomy - the study of how fossils get preserved How sedimentary rock deposits are formed and how dead animals get in them Help us understand ancient ecosystems Helps us understand biases in the fossil record Some organisms and parts of organisms rarely preserved www.fossilhut.com www.sonoma.edu/users/g/geist/bio.html Berlin specimen - 1877 Solnhofen specimen - 60’s www.cmnh.org www.hayashibara.co.jp/html/shinka/ paleo.cc/paluxy/livptero.htm Pterodactylus kochi leute.server.de/frankmuster/P/Pterodactylus.htm www.breckminerals.com www.johnsibbick.com/prehist-pages/pre-p-20.asp Ichthyosaur from Holzmaden www.urweltmuseum.de/Englisch/shop_eng/fossilienverkauf_eng.htm Brief history of bird origins debate Archae has teeth, hand claws, and a bony tail like dinos; but feathers like birds 1926 Heilmann decides birds did not descend from dinos because dinos lack wishbones (since found) 1964 Deinonychus discovered 1972 Walker suggests birds descended from an ancestral crocodilian Deinonychus www.dinosoria.com Ichnology: study of trace fossils Connecticut Valley dinosaur tracks described by Edward Hitchcock 1836 - 1858 www.amherst.edu/~pratt 1856 - Joseph Leidy publishes first description of North American dinosaur fossils Hadrosaur “duckbill” Stegosaurus ungulatus Stegosaurus stenops www.dinosaursinart.com Allosaurus fragilis www.dinosaursinart.com 1878 - Iguanodon mass grave found in Belgium http://digitalidesigns.net/ Brontosaurus, now called Apatosaurus Ornithischia “bird-hipped” Saurischia “lizard-hipped” 1889 - 1892 Hatcher finds 32 ceratopsians Torosaurus Pentaceratops www.amnh.org www.peabody.yale.edu www.geo.uw.edu.pl http://homepage.mac.com Western Diamondback Rattlesnake Komodo Dragon www.petinfo4u.com Pangolin Rhinoceros skin Ceratosaurus - first (1884) really good carnivore skeleton Charles Knight - the first great dinosaur illustrator 1902, 08 - Tyrannosaurus rex found at Hell Creek, Montana by Barnum Brown 1910 - new kinds of hadrosaurs Roy Chapman Andrews - the real Indiana Jones Franz Nopcsa Portions of the 1947 Zallinger mural at Peabody Museum, 110 ft wide by 16 ft high Two kinds of fossils: Body fossils: preserved body parts such as bones, shells, eggs, skin impressions Trace fossils: preserved marks on the planet left by activity of ancient organisms such as footprints, nests, toothmarks, coprolites, fossil regurgitates. Trace fossils are especially important because they tell us about behavior! How to fossilize a bone: Death followed by burial Permineralization – pore spaces in the bone are filled with minerals precipitated from groundwater Replacement –original material is replaced by other minerals. Rare in bones, common in wood. Complete permineralization and replacement = petrification. 10,000 years minimum fossilization time Sedimentary rocks www.mackenzieltd.com Igneous rocks www.neldamsbakery.com Sedimentary Rocks Record Environment Sedimentary rocks – accumulations of fragments of pre-existing rocks lithify OR minerals precipitate from aqueous solution A = Sandstone (beach environment) B = Shale (shallow marine environment) C = Limestone (deeper marine environment) Marine transgression – sea level rises limestone sandstone limey shale silty shale silty shale limey shale sandstone limestone Stratigraphic column resulting from a marine transgression Stratigraphic column resulting from a marine regression Sedimentary Rocks Record Environment Sediments come from eroding mountains Sediments sort by weight, so sand deposited at beaches, nearshore: makes sandstone Mud / clay deposited offshore: makes shale (too fine-grained to see individual grains) Calcite precipitated by marine organisms. Deposited in deeper waters where influx of terrestrial material is low: makes limestone Sedimentary Rocks Record Environment Sandstone and shale can also be formed from desert dunes, lake, river and floodplain, and delta deposits Most dinosaurs found in river, especially floodplain deposits A distinctive set of strata is called a formation Western Interior Seaway – 80 Ma www.oceansofkansas.com www.wvup.edu/ecrisp/fieldstudiesinutah.html Morrison Formation Laurasia rainbow.ldeo.columbia.edu Gondwana Morrison Formation Late Jurassic, 154-145 Ma Covers 1.5 million km2 western NA – outcrops in 13 states and 2 provinces of Ca Seasonally dry, especially in the south. Wetter and swampy (coal beds) in the north All kinds of plants and animals – conifers, ginkos, cycads, horsetails, frogs, fish, salamanders, pteros, mammals, dinos, probably mostly from riparian areas. Perennial water sources even in arid areas. www.colostate.edu http://en.wikipedia.org www.rainbow.ldeo.columbia.edu www.neiu.edu/~awroblew/ Hell Creek Formation Hell Creek Formation Latest Cretaceous, 67-65 Ma Montana, N and S Dakota, Wyoming K-T boundary, “fern spike” Rockies rising to west, huge amounts of sediment being shed into WIS, forming all kinds of great deposits – estuaries, tidal inlets, tidally-influenced fluvial channels, fluvial channels, alluvial plains, lacustrine basins, and coal swamps. Probably all related to a huge delta a la the Mississippi So how do I find a dinosaur? Get a geologic maps Colors represent a combination of age and type of rock exposed at surface Find an outcrop on non-marine, Mesozoic sedimentary rocks, go there Geologic Map of Arizona Clades: how we think about relatedness in this class Derived character: a feature of an organism that has changed from the ancestral condition. “Evolutionary novelties” Primitive character: a feature of an organism that has not changed from the ancestral condition Clade: a group of organisms that share derived characters A clade is a group of organisms that are more closely related to each other than they are to any other organisms Dinosaur “A reptile-like or bird-like animal with an upright posture that spent its life on land” Evolutionary novelties (shared derived characters): advanced mesotarsal ankle, femur with ball, pelvis with hole for femur ball. Allowed upright posture with legs under the body, not sprawled to side. This allowed high levels of activity! Three of more pelvic (sacral) vertebrae -----------Time---------→ Younger Older Phylogenetic tree = family tree