1. Ask The Class
Would you ever want to live in Antarctica, today? Why or why not?
What about 200 million years ago? Why or why not?
Do you think the world has always
looked how it does today? Explain.

2. OBJECTIVE:
Scientists will be able to prove Wegener’s theory of continental drift.

3. Quick Question!
1. What piece of evidence for Wegner’s Continental Drift Theory did you find the most compelling? Explain your answer.

4. QUESTIONS: Do you think a dinosaur could swim across oceans?
Could we walk to Africa?
What is a continent?
Is North America floating?

5. CONTINENTAL DRIFT
Look at this picture of the world. Which continents do you think look like they could fit together?

6. CONTINENTAL DRIFT
Did you notice Africa & South America?

7. PANGEA
225 million years ago, all the Earth’s continents were just one giant continent
This giant landmass that broke into our present day continents is called Pangaea

8. PANGEA Turn to the group across from you.
Answer these questions in your notebook.
How do your supercontinents look similar?
How do you supercontinents look different?
Who do you think is right? Why?

9. HOW DID WE KNOW THIS?? A: A science leader did the exact same thing you did just now!9

10. CONTINENTAL DRIFT
In 1910 a German scientist named Alfred Wegener wrote to his future wife: “Doesn’t the east coast of South America fit exactly against the west coast of Africa, as if they had once been joined?”

11. CONTINENTAL DRIFT
Alfred Wegener (a German scientist) was looking at the continents on a map and decided that they seemed like puzzle pieces
He suggested that maybe the continents had been one continent and for some reason drifted apart over millions of years
He decided to call his theory the theory of continental drift

12. CONTINENTAL DRIFT
200 million years ago (mya) there was one large super continent known as Pangaea.
Pangea = “one land” in Greek

13. CONTINENTAL DRIFT

14. CONTINENTAL DRIFT

15. CONTINENTAL DRIFT

16. CONTINENTAL DRIFT Four types of evidence: 1) Shorelines
2) Matching Fossils
3) Mountain Belts
4) Ancient Climates

17. FOSSILS
Several of the same fossil organisms were found on different continents that are now separated by vast amounts of water?
How did they get from one continent to another?

18. FOSSILS
For example, mesosaurus (dinosaur) fossils are found only on the east coast of South American and in Africa (mostly in the West)

19. FOSSILS
On your super continent circle or color in some areas with similar fossils!

20. BUT!! FOSSILS Counter explanation: Land bridges
Low sea levels could have allowed animals to cross the area by land.

21. FOSSILS
No fossils have been found in the Atlantic Ocean!

22. CONTINENTAL DRIFT Four types of evidence: 1) Coastlines
2) Matching Fossils
3) Mountain Belts
4) Ancient Climates

23. MOUNTAIN BELTS
Across the globe there are many matching rock types and mountain belts.
For example, the Appalachian Mountains run along North America, disappear and then reappear in Newfoundland.
When the continents are assembled, the mountains become continuous belts.

24. MOUNTAIN BELTS
For example, the Appalachian Mountains run along North America, disappear and then reappear in Newfoundland.
When the continents are assembled, the mountains become continuous belts.

25. CONTINENTAL DRIFT Four types of evidence: 1) Coastlines
2) Matching Fossils
3) Rock Types & Structures
4) Ancient Climates

26. ANCIENT CLIMATES
Wegener was a meteorologist, very interested in ancient climates.
Found similar glacial deposits dating back 200 million years in the southern portions of Africa, South America, & India.
Same glacial grooves showed that the same bands of glaciers covered the area.

27. ANCIENT CLIMATES

28. LET’S TALK ABOUT ANTARCTICA

29. Not everyone was sold on Wegener’s theory:
CONTINENTAL DRIFT
Not everyone was sold on Wegener’s theory:
"Wegener's hypothesis in general is of the footloose type…it is awkward, ugly.”
WHY??

30. CONTINENTAL DRIFT He couldn’t prove it!
Believed that the Moon created strong global tides that had forced the continents to break apart.
(imagine big waves breaking apart the continents)
Physicists said that tides that strong would have stopped the earth’s rotation. Could not exist!

31. CONTINENTAL DRIFT X

32. Plead your Case…
You will be writing a letter as Wegner to your fellow scientists
You will be picking one piece of evidence and defending that piece of evidence to the scientific community at the time.
Follow the directions carefully.

33. d. migration across land bridges
What hypothesis states that the continents were once joined to form a single supercontinent? (2.02)
Plate tectonics
Seafloor spreading
Continental drift
Paleomagnetism
What was the supercontinent in the continental drift hypothesis called?
a. Panthalassa
b. Pangea
c. Mesosaurus
d. Africa
What is one kind of evidence that supports Wegner’s hypothesis?
The same magnetic directions exist on different continents.
Major rivers on different continents match
Land bridges still exist that connect major continents
Fossils of the same organism have been found on different continents
What does evidence about ancient climates indicates?
a.glacial ice once covered much of what is now India and Australia
b.continents in the Northern Hemisphere today were once centered over the South Pole
c.continents in the Southern Hemisphere today were once centered over the North Pole
d.no continents occupied the Southern Hemisphere
How did opponents of continental drift account for the existence of similar fossils on widely separated continents?
A .parallel evolution
b. large ocean rafts
c. oceanic currents
d. migration across land bridges