continental drift copy - biology...

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?

Copyright © 2010 Ryan P. Murphy

Possible Answers!


● Area of Focus: Plate Tectonics


● 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)


• 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.


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.


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.


Learn more at… http://www.ucmp.berkeley.edu/geology/tectonics.html

http://www.ucmp.berkeley.edu/geology/tectonics.html

• In 1912, The German geologist Alfred Wegener proposed continental drift. – Not accepted until the 1950’s!


● Evidence for continental drift. ● - ● - ● - ● - ● -


● The shapes match.


● Same fossils found on different continents


● The same rock structures on different continents


Example

● Fossils of plants and animals on Antarctica


● Magnetic layers in sea floor spreading


• 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.


● Gondwondaland and Laurasia were two mega continents before Pangea.


• Future Supercontinent 250 million years from now.

• What causes continental drift and plate tectonics?


• Answer! – Convection currents (Remember heat rises)

move the plates


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