Geologic Time
Published on Nov 22, 2015
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MORE DECKS TO EXPLORE
PRESENTATION OUTLINE
PRECAMBRIAN
4.6 billion to 542 million years ago (88%)
PRECAMBRIAN EON
- Hadean-the time before Earth solidified
- Archean- first single-celled life
- Proterozoic- cyano bacteria
- Stromatolites generate oxygen for the atomshere
Photo by theqspeaks
PALEOZOIC ERA
542-251 million years ago
"CAMBRIAN EXPLOSION"
Life was thriving in the oceans and becoming more complex.
Photo by subarcticmike
ORDOVICIAN PERIOD
488-444 mya
ORDOVICIAN PERIOD
- Mollusks and arthropods ruled the oceans
- First true vertebrates arrived
- Life had yet to diversify on land
- Mostly graptolites, conodonts, and trilobites
- Ended with a mass extinction of 60% of marine species
Photo by jsj1771
SILURIAN ERA
- First bony fish with bony scales
- Eurypterids several METERS in length
- First land animals and plants
- Small land arthropods
Photo by Black Country Museums
PERMIAN PERIOD
- Largest mass extinction
- 70% land and 90% marine life
- Led the way to the Mesozoic Era
- Also known as the "Age of Dinosaurs"
Photo by Dallas Krentzel
TRIASSIC
- First period of the Mesozoic
- First dinosaurs appeared
- Then the first mammals
- Ended with drastic climate change
- Possibly extensive volcanism
Photo by Travis S.
JURASSIC PERIOD
- First giant dinosaurs
- The climate was warm & humid
- Oxygen rich atmosphere
Photo by Zachi Evenor
an impression in a substrate
Photo by Hypocentre
INDEX FOSSILS
are used to date the ages of rock layers
Half-Lifes
the time it takes for 50% of the parent isotope to decay to the daughter isotope
Photo by Vermin Inc
dinosaur footprint trace fossils
Photo by James St. John
dinosaur eggs
Photo by Charles D P Miller
permian extinction
Photo by Al_HikesAZ
