Aim: Have the continents always been where they are?

- You will have 10 minutes for this task. Do Now: - Take the “Continental Drift Theory” reading from the back top bin. - Answer the questions throughout the reading and then answer the three questions on the back. - You will have 10 minutes for this task.

I. The Continental Drift Theory - theorized that the continents floated around the planet through the oceans. Stop 1: Why is Wegener’s idea a theory? What does this imply? Alfred Wegener around 200 mya, all the continents were together in one land mass he called Pangea (all Earth).

What evidence made Wegener think the continents were all one unit? Question 1: What evidence made Wegener think the continents were all one unit?

II. Evidence for the Theory 1. The Continental Puzzle - continents fit together like a giant puzzle.

Formation of Pangaea (~300mya)

Why wasn’t Wegener’s theory initially accepted? Question 2: Why wasn’t Wegener’s theory initially accepted?

Lystrosaurus fossil, Africa 2. Matching Fossils - Fossils of similar organisms are found on different continents that are now far apart. Stop 2: In your own words, explain how the Glossopteris and Lystrosaurus fossils help support Wegener’s theory Glossopteris fossil, Australia Lystrosaurus fossil, Africa - With the continents positioned as they are today, these organisms cannot travel across the oceans to different continents.

3. Rock Types and Structures Present (2015) 250 Million Years ago - different mountain ranges across oceans have the same rock composition and age.

III. Rejecting a Hypothesis - Most scientists rejected Wegener’s hypothesis because he could not explain what causes the continents to move. Question 2: Why wasn’t Wegener’s theory initially accepted? Questions 3: Evaluate Wegener’s theory, do you agree with his ideas? How does the fossil evidence impact his theory? What questions would you ask Wegener?

IV. A New Theory Emerges The Theory of Plate Tectonics the continents are attached to the lithosphere (crust), and that the lithosphere moves carrying these continents. (still uses Wegner’s evidence)

Closure Although the continents are still moving today, we do not feel it happening. Where on planet Earth would you go to see evidence of the continents moving today?

Review Book Page 100 #’s 3 and 5

From the back of the room; - Take a green lab (top bin) - Take a white sheet with the “continental cut-outs” (bottom bin) Working with your lab partner; - Read the lab - Follow the directions - Materials are in the back of the room - Raise your hand if you are stuck