Today – 1/23Today – 1/23

• Critter in the news

• Reading background

• History of dinosaur discoveries

ScienceDaily.com

P-T extinction

Before: simple and complex marine ecosystems exist in equal numbers

After: complex marine ecosystems outnumber simple ones 3 to 1

Discovered because of the web and a new analytical approach

3-point XC opportunity

Tonight, 7:30 pm, Kuiper Space Sciences 308

Surface of Titan, a moon of Saturn

Check in with me before

Sit with me or 1-page summary

Admistration

First short writing assignment comments

Pick up papers in G-S 205

Posting grades

Last time:

River types – meandering vs. braided

Carbon isotopes

K-T impact

P-T scenario

5500 K

4800 K3500 K

The GeodynamoThe Geodynamo

Mid-Ocean Ridges (MOR’s)Mid-Ocean Ridges (MOR’s)

Magnetic Striping of the Sea Magnetic Striping of the Sea FloorFloor

MORs and Magnetic StripingMORs and Magnetic Striping

www2.nature.nps.gov/geology/usgsnps/animate

Magnetic striping of the seafloor

Convecting liquid outer core generates Earth’s magnetic field

Heat from the core and radioactive decay drives mantle convection and plate tectonics making new rocks at mid-ocean ridges

New rocks record polarity of Earth’s magnetic field!

IcelandIceland

Magnetostratigraphy

Drill a bunch of cores going up through layers

Analyze them to determine the pattern of magnetic polarity through time

Match them (like tree rings) to the appropriate part of the known pattern for Earth throughout time, read off the date

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

Importance of Hawkins

First attempt at full-scale reconstruction

Super-popularized dinosaurs

Cemented wrong views!

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