Precambrian Era
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Transcript of Precambrian Era
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Precambrian EraPrecambrian Era
4,600,000,000 years ago to 570,000,000 years ago4,600,000,000 years ago to 570,000,000 years ago
85% of Earth’s History85% of Earth’s History
Simple life starts in the oceans
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The Earth FormsThe Earth Forms
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4.6 BYA4.6 BYA
Surface cools, forming the crust
Oldest rock found in Western Australia primitive atmosphere forms from volcanic
eruptions (No Free oxygen gas).
Oceans form (from water vapor released in eruptions & maybe comets)
4.3 BYA4.3 BYA
A molten Earth forms
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Comparison of AtmospheresComparison of Atmospheres
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3.5 BYA3.5 BYAOldest fossils of bacteria (prokaryotes).
Simple & small with no nucleus
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Miller/Urey Experiment (1953)Miller/Urey Experiment (1953)
Tried to create life from a simulated primitive atmosphere.
Instead created complex molecules, but no cells.
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What does it mean to be living?What does it mean to be living?
Be able to reproduce
Uses energy
Composed of one or more cells
Contains genetic information
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Where did Life Start?Where did Life Start?
Oceans (nutrient rich, possibly with complex molecules)
Ice (opportunity for organization)
Meteorites (rich with building blocks of life)
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First Cells?First Cells?
complex molecules (RNA) replicating inside coacervates (similar to cell membrane).
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3.0 BYA3.0 BYACyanobacteria (blue-green algae)
evolve creates energy from photosynthesis giving off oxygen gas (beginning to
form the atmosphere of today). Form large stromatolites (below)
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1.5 BYA1.5 BYA Eukaryotes (complex, larger,
single celled organisms) evolve from prokaryotes (bacteria).
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630 MYA630 MYA Multicellular organisms evolve with soft bodies
Species include: jelly fish; coral stalks; segmented worms; algae