1. What fossils can you find in Michigan? How do fossils form?
May 25, 2011
What fossils can you find in Michigan?
How do fossils form?

2. Trace Fossil Indirect evidence left behind Footprints Burrows
Animal waste

3. Dinosaur Ridge
Morrison, Colorado

6. Molds and Casts
Organisms buried in sediment may decay or dissolve away leaving a mold.
If the space fills with sediment, an external cast can be made.
Molds and casts are three dimensional and preserve the surface contours of the organism.

7. Replacement Original organism material is replaced by minerals
Can leave replicas of hard tissue (shells, bones, etc) or soft tissue (muscle, fat, etc)

8. Petrified
Empty spaces are filled with minerals

9. Amber
Tree sap hardens into amber
Preserves specimen

10. Original Material
Mummified/frozen organisms

11. Who studies fossils?
Paleontologists
Reconstruction of Ichthyosaurus.

12. rock formed by the growth of blue-green algae or cyanobacteria
stromatilite
Trace fossil
rock formed by the growth of blue-green algae or cyanobacteria

13. ammonites
Replacement/Mold and Cast
415 million years ago

14. Today’s organisms believed to be derived from ammonites

15. ~225 mya Triassic period 4 x harder than granite
Petrified Wood
~225 mya Triassic period 4 x harder than granite

17. Fossils in Michigan Are there dinosaur fossils in Michigan?
There was at one time, but not now!
The right age rock isn't there anymore.
Glaciers came and eroded the land
The rocks exposed to the ground are too old to hold dinosaurs or just junk sediment
Dinosaurs lived between 235 million years to about 65 million years ago.

18. Fossils in Michigan: We may not have dinosaur fossils, but we do have
PETOSKEY STONES!
Fossils from coral reefs: Hexagonaria percarinata
Devonian Period, ~ 360 million years old
can be found on the shores of Lake Michigan and Lake Huron

19. Where have mammoths been found in the United States?
Many states, but the most have been found in Nebraska
About 10,000 years old

20. Best Preserved Fossil EVER 37,000 years ago Baby Wooly Mammoth (2007) found in Siberia
Prehistoric Mammoth Discovered
Quick Baby Mammoth Clip
Frozen Mammoth Found
Mastodon found in Rochester

21. Ashfall Fossil Beds Location = northeast Nebraska
Hundreds of skeletons of prehistoric animals have been found in a volcanic ash bed buried beneath the rolling farmlands of northeastern Nebraska. Some of the best-preserved fossil rhinos, horses, camels, and birds
Map of Land

23. Ashfall Fossil Beds How it happened…
Volcano in southwest Idaho erupted and spread a blanket of ash over a very large area
One or two feet of this powdered glass covered the flat savannah-like grasslands of northeastern Nebraska = killed animals
Most of the animals survived the actual ashfall
They grazed on the ash covered grasses and their lungs began to fill up with the abrasive powder.
Soon their lungs became severely damaged and they began to die.
The smaller animals died first (smaller lung capacities)
Finally, after perhaps three to five weeks, the last of the rhinos perished.
Their bodies were quickly covered by the blowing and drifting ash

24. KT Crater (asteroid crater)
Extinction
Impact
High levels of Iridium (rare on earth, but common in meteorites)
Thought to have caused extinction of dinosaurs

25. Where did life come from?
First idea: spontaneous generation
Disproven by Francesco Redi, Italy (1668)
Used rotting meat and maggots/flies
Showed flies/maggots didn’t appear in closed containers, only open ones

26. Where did life come from?
Next Idea: Theory of Biogenesis
Living organisms only come from other living organisms
Louis Pasteur
Nutrient broth only allowed growth after being contaminated with air

27. Where did life come from?
First living organism
Believed to arise because of primordial soup
Like a big mixing bowl of atoms  molecules  macromolecules  organism
Simple prokaryote like archaea
Remember: no oxygen! Archaea like extreme enviros!

28. Where did life come from?
Cyanobacteria (~3.5 bya)
photosynthesizing bacteria
produce oxygen thru photosynthesis!
Eukaryotes (~1.8 bya)
Endosymbiont theory
Margulis (1966)
Prokaryotes and eukaryotes had mutualistic relationship, that’s how we got mitochondria and chloroplasts!