today – 1/18
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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: To learn how mammals survived the end-Permian extinction event Evidence of dinosaur ancestors - PowerPoint PPT PresentationTRANSCRIPT
Today – 1/18Today – 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 end-Permian 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
/www.uky.edu/AS/Geology/howell
Meandering river
Braided streams
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 protons98.9 % of carbon atoms have 6 neutrons, called C-121.1 % have 7 neutrons, called C-13Plants prefer C-12Scientists measure ratio in rocks, try to explain observationsStable 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)
1980 - Walter and Luis Alvarez discover
iridium rich clay layer
www.physast.uga.edu/~jss/
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!
www.windows.ucar.edu/earth/images/chicxulb.gif
Chicxulub - “tail of the devil”
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, Asteroid 1950-DA, March 16, 28802880
Unlike the K-T impact that killed the dinos, the cause of the P-T extinction is still the subject of vigorous debate!
http://jan.ucc.nau.edu/~rcb7/
X
Pangea
Tethys
Sea
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 parentsPhysiology - thermal regulation, growth patternsHistory of life - speciation and extinction, relationships among groupsEnvironmental reconstruction, rock ages geochemistry, paleogeography, interaction between physical and biological worlds
www.dinoland.dk
web.ukonline.co.uk/conker/
← Griffin inspired by Protoceratops? ↓
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
home.uchicago.edu/~shburch/dinopaper.html
1830’s – Meet Meg, plus the happy water lizard
1831
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 legs1842 – 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 themHelp us understand ancient ecosystemsHelps us understand biases in the fossil recordSome organisms and parts of organisms rarely preserved
www.fossilhut.com
Solnhofen specimen - 60’sBerlin specimen - 1877www.sonoma.edu/users/g/geist/bio.html
www.cmnh.org
paleo.cc/paluxy/livptero.htm
Pterodactylus kochi
leute.server.de/frankmuster/P/Pterodactylus.htm
www.hayashibara.co.jp/html/shinka/
Ichthyosaur from Holzmaden
www.urweltmuseum.de/Englisch/shop_eng/fossilienverkauf_eng.htm
www.johnsibbick.com/prehist-pages/pre-p-20.asp
www.breckminerals.com
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
www.dinosoria.com
Deinonychus
www.amherst.edu/~pratt
Connecticut Valley dinosaur tracks described by Edward Hitchcock 1836 - 1858
Ichnology: study of trace fossils
1856 - Joseph Leidy publishes first description of North American dinosaur
fossils
Hadrosaur “duckbill”
www.dinosaursinart.com
Stegosaurus stenops
Stegosaurus ungulatus
www.dinosaursinart.com
Allosaurus fragilis
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
www.geo.uw.edu.pl
www.amnh.org
Torosaurus Pentaceratops
www.peabody.yale.edu
http://homepage.mac.com
Western Diamondback Rattlesnake
Komodo Dragon
Pangolin
Rhinoceros skin
www.petinfo4u.com
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
www.mackenzieltd.com
Sedimentary rocks
Igneous rockswww.neldamsbakery.com
Sedimentary Sedimentary Rocks Record Rocks Record EnvironmentEnvironment
A = Sandstone (beach environment)B = Shale (shallow marine environment)
C = Limestone (deeper marine environment)
Sedimentary rocks – accumulations of fragments of pre-existing rocks lithify OR minerals precipitate from aqueous solution
Marine transgression – sea level rises
Stratigraphic column resulting from a
marine transgression
Stratigraphic column resulting from a
marine regression
sandstone
silty shale
limey shale
limestone
silty shale
limestone
sandstone
limey shale
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
www.oceansofkansas.com
Western Interior Seaway – 80 Ma
www.wvup.edu/ecrisp/fieldstudiesinutah.html
Morrison Formation
rainbow.ldeo.columbia.eduGondwana
Laurasia
Morrison Formation
Late Jurassic, 154-145 MaCovers 1.5 million km2 western NA – outcrops in 13 states and 2 provinces of CaSeasonally 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
www.rainbow.ldeo.columbia.edu
http://en.wikipedia.org
www.neiu.edu/~awroblew/
Hell Creek Formation
Hell Creek Formation
Latest Cretaceous, 67-65 MaMontana, N and S Dakota, WyomingK-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
Phylogenetic tree = family treeOlder
Younger--
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