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8 Cards in this Set
- Front
- Back
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Phanerozoic Eon |
-divided into 3 eras with each era divided into periods -Paleozoic Era: 542 to 251 million years ago -Mesozoic Era: 251 to 65 million years ago -Cenozoic Era: 65 million years ago to present |
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Paleozoic Era
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-The Cambrian Explosion 542 million years ago saw single celled bacteria evolve into an abundance of diverse organisms
- As much as 96% of all life on Earth went extinct even known as the P-T extinction -early cambian/ ordoovician periods: mollusks, arthropods |
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Mesozoic Era
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- the rise of the dinosaurs
-->the Jurassic period, dinosaurs had become the largest and most dominant form of life on Earth -->the continents were combined into a supercontinent known as Pangea -Mild: Jurassic -birds, Pangaea breaks up -late: creatous |
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Cenozoic Era
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-Pangea, the supercontinent that existed during the 'Age of the Dinosaurs' had split apart, shifting the continents into the positions we see today.
-Paleogene period: climate becomes cooler and dryer -Neogene period: north and south America connect -Quaternary period: Pleistocene epoch: 2.6 mya- 12,000 mya -homo habillis--> made home tools -H. errectus: only homosapiens survive |
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Hadeon Eon Time |
-4,200 mya: large oceans form -4,055 mya: oldest known rocks -no life -the surrounding earth is from a dead star -the moon is Earth, it just fell apart |
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Archean Eon |
early life -evidence of life: 3,850 mya -oddest fossils: 3,500 -fossil: bone or imprint of cell -reducing atmosphere: allows sugar, amino acid -produced biochemical, all organic chemicals just lay there -rays prevented life from living unless you were under a rock or water -first thing probably heterotrophic and probably barely alive -ecosystem evolution: autotrophic--> making food themselves-easier -oxygenic photosynthesis -stromatolites |
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oxygenic photosynthesis |
-under anerobic conditions: ion dissolved in water and ocean full of iron -oxygen instantly disappeared when it touched iron because it rusted -eventually aerobic organisms were built -mitochondria are actually ancient - |
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Proterozoic Eon |
-banded iron formations: 2,500 mya -atmospheric oxygen: 2,200 mya -oxygen level at 3% by 1,000 mya -oldest eukaryote fossils: about 1,800 -oldest animal fossils; 600mya sponges -Acritarchs are small organic fossils -early multicelled fossils: dickinsonia costata |
