chapter 17 plate tectonics section 17.1 drifting continents

Chapter 17Chapter 17Plate TectonicsPlate Tectonics

Section 17.1Section 17.1

Drifting ContinentsDrifting Continents

VocabularyVocabulary

Continental Drift:Continental Drift: The hypothesis that the continents slowly move The hypothesis that the continents slowly move

across Earth’s surface.across Earth’s surface.

Fossil:Fossil: A trace of an ancient organism that has been A trace of an ancient organism that has been

preserved in rock.preserved in rock.

Pangaea:Pangaea: The name of the single landmass that broke apart 200 The name of the single landmass that broke apart 200

million years ago and gave rise today’s continents. million years ago and gave rise today’s continents.

The Theory of Continental DriftThe Theory of Continental Drift

State Alfred Wegener’s hypothesis about State Alfred Wegener’s hypothesis about how Earth’s continents have moved.how Earth’s continents have moved.Wegener’s hypothesis was that all the Wegener’s hypothesis was that all the

continents had once been joined together continents had once been joined together in a single landmass and have since in a single landmass and have since drifted apart.drifted apart.

Wegener named his supercontinent Wegener named his supercontinent ________.________.Pangaea


What did Wegener think had happened to What did Wegener think had happened to this supercontinent?this supercontinent?Wegener thought that this supercontinent Wegener thought that this supercontinent

had broken apart and that the pieces had had broken apart and that the pieces had slowly moved to become the continents as slowly moved to become the continents as they are today.they are today.

Wegener’s idea that the continents slowly Wegener’s idea that the continents slowly moved over Earth’s surface became moved over Earth’s surface became known as ____________.known as ____________.continental drift


Complete the concept map.Complete the concept map.

Continental drift

Landforms

Fossils

Climate

Is supported by evidence from


Give an example of evidence from Give an example of evidence from landforms that supported Wegener’s idea landforms that supported Wegener’s idea of continental drift.of continental drift.An example is mountains in South Africa An example is mountains in South Africa

that line up with mountains in Argentina or that line up with mountains in Argentina or coal fields in Europe that match up with coal fields in Europe that match up with coal fields in North America.coal fields in North America.

Any trace of an ancient organism Any trace of an ancient organism preserved in rock is called a(n) ________.preserved in rock is called a(n) ________.fossil


How did Wegener explain similar fossils How did Wegener explain similar fossils on different continents?on different continents?Wegener explained it as evidence that the Wegener explained it as evidence that the

continents had once been united.continents had once been united.True or False: Wegener believed that True or False: Wegener believed that

Earth’s climate had changed.Earth’s climate had changed.FalseFalse

Scientist’s Reject Wegener’s Scientist’s Reject Wegener’s TheoryTheory

How did Wegener think that mountains formed?How did Wegener think that mountains formed? Wegener thought they formed when drifting Wegener thought they formed when drifting

continents collided, causing their edges to continents collided, causing their edges to crumple and fold.crumple and fold.

How do the locations of mountains support How do the locations of mountains support Wegener’s ideas how mountains form?Wegener’s ideas how mountains form? Mountains usually occur in narrow bands along Mountains usually occur in narrow bands along

the edges of continents, as you would expect if the edges of continents, as you would expect if the collision of continents forms mountains. the collision of continents forms mountains.

chapter 17 plate tectonics section 17.1 drifting continents

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