Today – 1/18
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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