Geologic Time Flashcards
End of Precambrian
Because life began to flourish (Animals began to have hard, scales on them)
End of Paleozoic
“The Great Dying”
End of Mesozoic
Meteor hits Earth
Difference b/w geologic eons, eras, periods, and epochs
Eons are subdivided into eras, which are subdivided into periods, which are subdivided into epochs
How did the core form? (Precambrian)
Iron collected from nebular debris melted due to increasing temperature on Earth, then sunk into middle of Earth
how did Oceans form? (Precambrian)
Earth began to cool, and water vapor began to condense to form clouds, which caused torrential rains
How an oxygen atmosphere formed? (Precambrian)
From stromatolites
What was the first life?
Bacteria that did not need oxygen, and could withstand high temperature and pressure
What was the dominate life form in Paleozoic?
Trilobites
What did the globe look like during Paleozoic Era?
Gondwanaland; North America near equator and most of world still under water
What is Gondwandaland?
Southern continents joined into a single landmass during Paleozoic
What is Laurasia?
Landmasses that broke away from Gondwandaland in Northern Hempishpere
When did most of the coal deposits form?
Paleozoic during Mississippian due to the forests of the time
When did the first fish appear
Ordiovcian Period during Paleozoic era (505 mya)
When was the age of fishes ?
Devonian Period (408 Mya) during Paleozoic era
What was the biggest mass extinction?
The Great Dying which ended the Paleozoic era
What was the Great Dying?
Caused by Siberian Traps which produced C02, which warmed the atmosphere and oceans, which killed 95% of ocean species because warm water can’t hold CO2, which made bacteria that produces hydrogen sulfide (poison) flourish, Hydrogen Sulfide bubble into atmosphere, causing 95% of land species to die
Climate of Mesozoic
Warm, dry climate
Dominate life of Mesozoic Era?
Dinasaurs
Triassic Dinosaurs
Small
Cretaceous Dinosaurs
intelligent and large
Evidence that supports the asteroid theory as the reason for dinosaur extinction
Irridium-> and element found in space rocks was found worldwide in K/T rock; Shocked quartz found in K/T rocks; Crater found
What can fossil footprints tell us?
Help to understand dino behavior; Learn if a specific dino travels in herd or not; Can estimate the speed and gait of the dino; Can estimate the size of the dino
Dominate life of Cenozoic
Birds and mammals
When did humans appear during the Cenozoic era?
The Quaternary Period
Mammoths
Curved tusks; Related to modern elephants
Mastodons
Straight tusks; Michigan’s state fossil
When did the Earth form?
4.6 million years ago
How did the moon form?
From an astrode hitting Earth, and pushing rock into the ring around Earth; The debris came together to form the moon
How did the first continents form?
Tectonic plates allowed for lava and volcanos to emerge, creating volcanic islands from lava; The islands came together to form continents
What is Pangea?
A super continents that was broken up due to tectonic plates
Cold Oysters Seldom Develop Many Precious Pearls, Their Congeal Too Quickly
Cambrian, Ordovician, Silurian, Devonian, Mississippian, Pennsylvanian, Permian, Triassic, Jurassic, Cretaceous, Tertiary Quaternary
Put Eggs On My Plate Please Homer
Paleocene, Eocene, Oligocene, Miocene, Pliocene, Pleistocene, Holocene
Cambrian
First shelled organsims; Trilobites dominate
ordovician
First Fish
Silurian
First land plant
Devonian
First amphibians
Mississippian
Large primitive trees; Coal
pennsylvanian
Abundant insects; First reptiles
Permian
End of trilobites and other marine animals
Triassic
First dinosaurs (small); Primitive mammals (have fur)
Jurassic
First Birds/mammals; Abundant dinosaurs (reaching larger sizes)
Cretaceous
First flowering plants; Seasons due to cooling; Pangea splits; T-Rex and raptors (intelligent dinosaurs)
K/T Boundary
Division between Cretaceous and Tertiary
Tertiary
Climate continues to cool; First Primates
Quaternary
Ice Age; Formation of Great Lakes; First Hominoids; Mammoths and Mastodons
Paleocene
First Primates
Eocene
First Horse
oligocene
Dogs, cats, and pigs
miocene
Arctic become covered with ice
Pliocenes
First hominoids
How to become a fossil
- Animal dies; 2. Needs to be quickly buried (in order to avoid being eaten or rotting); 3. Conditions must be perfect (Perfect temp, pressure, acidity, chemical comp, moisture levels); 4. Water infused with minerals must seep into bones, where, overtime, bone decay and is replaced by rock like minerals
Geologic Time calendar Conversion
365/4,600,000,000 x Days before present (Dec.31) / Age you want to know
Precambrian era ended because…
Life began to flourish due to having enough o2 in atmosphere
Era
Mass extinction of dominant species
Period
New dominant species
Epoch
New dominant mammal
When will the Cenozoic era end?
When there is a mass extinction
Paleozoic animals
Trilobite; crinoid; colonial coral; fern; horn coral ; brachiopod ; fish; cephalopod
Stromatolites
Precambrian
Ammonite
Mesozoic
Laurasia
Northern Hemisphere
Laurasia + Gondwanaland
Pangea
Order of events of Precambrian
- Meteorites combine to form earth; 2. Iron sinks to center of earth;3. Moon formed; 4. Volcanoes create first atmosphere; 5. Comet hits earth and brings water to planet; 6. Relentless rain floods entire earth; 7. First life on earth appears (Cyanobacteria); 8. Banded iron formations form; 9. Stromatolites release o2 into atmosphere; 10. Pangea forms
Longest era
Precambrian
