continental drift copy - biology...
TRANSCRIPT
Lesson #8: Continental DriftObjective:Create and use a model to
discuss the evidence that supports the theory of continental drift.
Please pick up the three paged handout from the front. Copy lesson#, title, and objective in your notebook and title page.
Question? Look at the map below, do see any puzzle pieces, if so were would they fit?
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Possible Answers!
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Copyright © 2010 Ryan P. Murphy
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Copyright © 2010 Ryan P. Murphy
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● Area of Focus: Plate Tectonics
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● Plate tectonics: The earth’s crust and upper mantle are broken into sections called plates. ● These plates float on the mantle like rafts
(moving very slowly)
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• There are 8 primary plates and several more secondary plates that make up the earth’s landmass.
• African Plate, Antarctic Plate, Australian Plate, Eurasian Plate, Indian Plate, North American Plate, Pacific Plate, South American Plate.
• The speed at which the plates move is about the speed at which your fingernails grow.
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SlowestThey are all slow
The African Plate's speed is estimated at around
2.15 cm (0.85 in) per year
• The speed at which the plates move is about the speed at which your fingernails grow.
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The yearly distance traveled varies from plate to plate. Some move at 3 centimeters while other's move around 6 cm per year.
FastestTonga Microplate Samoa 24 cm (9.4 inches) a year.
● Continental Drift: The gradual movement of the continents across the earth.
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Learn more at… http://www.ucmp.berkeley.edu/geology/tectonics.html
• In 1912, The German geologist Alfred Wegener proposed continental drift. – Not accepted until the 1950’s!
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● Evidence for continental drift. ● - ● - ● - ● - ● -
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● The shapes match.
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● Same fossils found on different continents
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● The same rock structures on different continents
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Example
● Fossils of plants and animals on Antarctica
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● Magnetic layers in sea floor spreading
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• 800 million years before Pangea, the continents were together in the supercontinent Rodinia.
• Climatic changes created a snowball earth where the entire planet was covered in a mile thick of ice.
● Pangea: The “Supercontinent” ● All of the plates were once together.
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● Pangea: The “Supercontinent” ● All of the plates were once together.
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● Gondwondaland and Laurasia were two mega continents before Pangea.
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• Future Supercontinent 250 million years from now.
• What causes continental drift and plate tectonics?
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• Answer! – Convection currents (Remember heat rises)
move the plates
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