1. Warm Up #9
What was Pangaea?

2. Lesson 1: The Continental Drift Hypothesis
Ch. 2 Plate Tectonics
Lesson 1: The Continental Drift Hypothesis

3. Essential Questions What evidence supports continental drift?
Why did scientists question the continental drift hypothesis?

4. Can you put the pieces together? ACTIVITY
Scientists use different types of evidence to show that Earth’s continents once were joined. How have scientists reconstructed Gondwana, a large ancient continent that was made of many continents?
Use a pair of scissors to carefully cut out each landmass along the outer grey line.
Arrange the puzzle pieces to construct a model of Gondwana.
Once you are sure you are correct glue to pieces down on your piece of paper.
What do you notice about the land masses?

5. Pangaea
Each year, North America moves a few centimeters closer to Asia
Earth moves slowly every day
Alfred Wegener proposed the idea of Pangaea – a supercontinent where all the continents were once part of
Continental drift was proposed, which suggests that continents are in constant motion on the surface of Earth
This is a hypothesis

6. Evidence that Continents Move
Continents fit together like puzzle pieces
Climate Clues – glacial grooves seen in South America, Africa, India, and Australia that are all the same

7. Evidence that Continents Move
Fossil Clues – fossils of similar organisms have been found on several continents separated by oceans
How do you think this happened?
Rock Clues – similar rock structures, formation, and aged rocks are on different continents separated by oceans

8. What was Missing?
Wegner’s idea about continental drift wasn’t accepted until way after his death
Due to continents moving so slow scientists didn’t believe him
Wegner couldn’t explain what caused the continents to move

9. Questions What is continental drift?
What is the evidence that supports continental drift?
What direction has South America moved relative to Africa?