Download Archaeopteryx!

Today – 2/6
• Critter in the news
• Famous USA depositional environments
and resulting rocks
• How to find a dinosaur
• Phylogenetic trees
.5 XC pt quiz – use whole sheet
Theropod (meat-eating dinosaur)
eggs were laid:
a) all at once, firehose-style, like
crocs
b) one at a time like birds
c) two at a time
d) different theropods had different
styles
Archaeopteryx!
Administration:
Test 2/15 – review sessions next Tuesday
and Wednesday, 5-6:30, right here
Hmwk 2 postponed
NASA Space Grant
Last time
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
The three rock types
Sedimentary rocks – derived from the
weathering of pre-existing rocks, or
precipitated from aqueous solution
Igneous rocks – crystallized from liquid
magma or lava
Metamorphic rocks – sedimentary rocks
that have been physically and/or chemically
altered by heat and/or pressure without
melting
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)
Cape Hatteras, North Carolina
Mississippi Delta
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
Sedimentary rock layers are called strata
A distinctive set of strata is called a
formation
Sundance
Sea
www.wvup.edu/ecrisp/fieldstudiesinutah.html
Morrison Formation
Laurasia
Gondwana
rainbow.ldeo.columbia.edu
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
www.wyomingtalesandtrails.com/bonewars2.html
http://en.wikipedia.org
www.rainbow.ldeo.columbia.edu
Western Interior Seaway – 80 Ma
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 map
Colors represent a combination of age and
type of rock exposed at surface
Look at the legend, find an outcrop on nonmarine, Mesozoic sedimentary rocks, go
there
Score major dinosaurs!
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
A lineage of tetrapods
developed eggs with
membranes that could
survive on land,
became amniotes
A lineage of fish
developed feet,
became the first
tetrapods (basically
amphibians)
diapsids – two holes
behind the eye socket
Eye socket
Eye socket
Eye socket
synapsids –
one hole
behind the
eye socket
anapsids – no holes
behind the eye socket