Plate Tectonics Flashcard

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Using ONLY maps, scientists observed that–

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the shapes of the continents allowed them to fit together.

Front

The distribution of fossils is used as evidence for plate tectonics. The distribution of four different fossil organisms over three different continents is shown in the diagram. The distribution of which organisms can be used as evidence that Africa was once connected to South America? (Options: Lystrosaurus, mesosaurus, and glossopteris; Cynognathus, glossopteris, and lystrosaurus; Glossopteris, cynognathus, and mesosaurus; Cynognathus, mesosaurus, and lystrosaurus)

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Glossopteris, cynognathus, and mesosaurus

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By studying the distribution of different types of fossils, geologists have determined that some plates have traveled great distances. Evidence to support this comes from the fact that-

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fossils of organisms that lived in warm climates have been found in arctic environments.

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Why are the fossils of Mesosaurus found today in some rock layers in both South America and Africa?

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Fossils of Mesosaurus are found in both South America and Africa because the continents were once connected as a single landmass millions of years ago and have moved great distances to their current location today.

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How are fossils used by scientists to show that the theory of continental drift is correct?

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They show us how the continents were connected together, by demonstrating how fossils on one continent were present on other continents at the same time, even though the animals could not have crossed an ocean if there was one in the way. This means that they must have been able to walk from one continent to another because the continents all made one giant landmass.

Front

Why do scientists believe that some tectonic plates are moving away from each other?

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Because at one point they were connected. They have since separated, so they must be moving away from each other.

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Name one of the scientists who contributed to the theory of continental drift.

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Alfred Wegener

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There is an idea or theory that the large masses of land all over Earth were at one time all connected as the Pangaea, or _____________________________.

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supercontinent

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Scientists believe Earth’s _______________________ are ___________________, or gradually moving.

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continents are drifting

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The pieces of Earth’s crust and uppermost mantle are referred to as _____________________________ or lithosphere.

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tectonic plates, tectonic plate