Transcript Continental Drift Theory

Aim: Have the continents
always been where they are?
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 5 minutes for this task.
I. The Continental Drift Theory
- theorized that the continents
floated around the planet
through the oceans.
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).
II. Evidence for the Theory
1. Matching Fossils
- Fossils of similar organisms are found on
different continents that are now far apart.
In your own words, explain how the Glossopteris and
Lystrosaurus fossils help support Wegener’s theory
Glossopteris fossil, Australia
Lystrosaurus fossil, Africa
2. The Continental Puzzle
- continents fit together like a giant puzzle.
Formation of Pangaea (~300mya)
3. Rock Types and
Structures
Present (2015)
- different
mountain ranges
across oceans
have the same
rock composition
and age.
250 Million Years ago
Question 1:
What evidence made Wegener think the continents were all one
unit?
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