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Today – 1/16. Critter in the news Beginning and end (?) of dinosaurs First writing assignment. .5-pt XC quiz:. The Karoo is: a river in Uganda an extinct bird a mild east wind in Botswana a desert in South Africa all of the above. Administration:.
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Today – 1/16 • Critter in the news • Beginning and end (?) of dinosaurs • First writing assignment
.5-pt XC quiz: The Karoo is: a river in Uganda an extinct bird a mild east wind in Botswana a desert in South Africa all of the above
Administration: • “Get to know you” form worth 2 pts XC • Ross’ OH: Th 2:30-3:30 • Note taker • D2l
Possible test question: Scientists think that the oldest known fossil cancer, a softball-sized dino tumor, may have: resulted from an injury sustained in competition for a mate been caused by a virus started during a teenage growth-spurt all of the above
Stratigraphy: • Study of rock layers • Reconstruct ancient environments and the evolution of ancient landscapes • Correlate rocks of same age that are widely separated geographically • Biostratigraphy, magnetostratigraphy, carbon isotope stratigraphy
http://www.utexas.edu/tmm/npl/rudist2005/images/Rudists.html
www.nhmc.uoc.gr Biostratigraphy
www.museums.org.za/sam/resource/palaeo/cluver/time.htm Karoo Biostratigraphy
Diictodon www.museums.org.za/sam/ Gorgon↓ www.mathematical.com Lystrosaurus↑ www.kjzg.com.cn
Fate of mammal-like reptiles at the end of the Permian: • Dicynodonts – “two dog-teeth” mostly die out except for Lystrosaurus, famous as evidence for continental drift. Herbivores • Gorgonopsians all die out. Top predators of the day. Last gorgonopsian = end of Permian • All had five fingers and toes, sprawling stance. Stance bad for breathing, activity level
www.earthsci.unimelb.edu.au/Thomas Biostratigraphy
Principle of faunal succession • “Fossil species succeed each other in a definite and recognizable order” • Sedimentary rocks represent time: lower = older, upper = newer • Distinctive fossils or assemblages of fossils can be used to correlate widely separated rocks as being the same age. Shelly marine fossils and microfossils, and pollen are usually best – widespread and distinctive.
Some lingo • Species: a population of organisms that can interbreed to produce fertile offspring • Genus: a collection of one or more species • Genera: plural of genus • Gradualism, uniformitarianism: biological and geological changes happen very slowly through time – nothing exciting ever happens Genus species – Tyrannosaurus rex
http://strata.ummp.lsa.umich.edu/jack/ Diversity of marine animals through time
Five major mass extinctions, where 50% or more species go extinct: • Three are of interest to us: • Permo-Triassic, 250 Ma – made way for the ancestors of the dinosaurs (archosaurs) • End Triassic, ~ 200 Ma – took out last of large archosaur competition to the dinosaurs • K-T, 65 Ma, • took out dinos
www.fossilmall.com www.trilobites.info Some organisms that disappeared at the end of the Permian http://members.aol.com/Waucoba5/dv/owensvalleygroupfusulinids2
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!
1 pt XC outline, groups of 3-4 Title 3 or 4 printed names 1) First paragraph – summary of content a) the find b) the interpretation … 2) Second paragraph – questions a) … 3) Third paragraph – affective discussion a)
Chicxulub - “tail of the devil” www.windows.ucar.edu/earth/images/chicxulb.gif
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/
Unlike the K-T impact that killed the dinos, the cause of the P-T extinction is still the subject of vigorous debate!
Tethys Sea Pangea X http://jan.ucc.nau.edu/~rcb7/ The blue planet, 260 Ma
http://dsc.discovery.com Siberian Traps
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 1830’s – Meet Meg, the happy water lizard home.uchicago.edu/~shburch/dinopaper.html 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”
Benjamin Waterhouse Hawkins’ 1853 dinosaur reconstructions being prepared for display in the Crystal Palace, Hyde Park, London http://www.ric.edu/rpotter/cryspal.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
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 Berlin specimen - 1877 www.sonoma.edu/users/g/geist/bio.html Solnhofen specimen - 60’s