Transcript Chapter 5 Section 3 - Science with Ms. Flythe

Chapter 5; Section 3
Drifting Continents
Question…
Do you
see the
pieces of
the
jigsawpuzzle?
• You and a partner will have 5 minutes to
complete the puzzle…
Here’s what to do…
1. Cut it up! Cut out each puzzle piece; cutting as close to
2.
3.
4.
5.
the lines as possible (it doesn’t have to be perfect).
What’s the code? Use the legend to identify the
symbols on each island or continent.
Puzzle me this. Look at the shapes of continents and
islands. What landmasses seem to fit together?
Let’s ROCK! Examine the evidence and try to match up
landmass boundaries that show similar rock strata,
fossilized desert belts, and dinosaur fossils.
Hold that Pose! Look over the arrangement of the
continents and islands and decide if the position of any of
them should change. When you are satisfied with your
map of Pangaea, glue it down on the world map.
• 1700’s – geologists thought that the
continents had always remained in the
same place
• Early 1900’s – Alfred Wegener (VAY guh nur)
thought continents could have once been
joined together as one landmass
Wegener hypothesized…
• All continents were once joined
together in a single landmass and
have since drifted apart
– This idea became know as continental drift
According to Wegener…
• Continents drifted together to form
Pangaea (the supercontinent)
– Means “all lands”
– Existed about 300 million years ago
• Over 10’s of millions of years ago,
Pangaea began to break apart
– Continents slowly moved to positions they are
today
Wegener gathered evidence…
• From different areas in science to support
his ideas
– Land features
– Fossils
– Climate change
Evidence from Land Features…
• Mountains of Africa & S. America lined up
• European coal fields matched up with
fields in N. America
Evidence from Fossils…
• Fossil – any trace of an ancient organism
that has been preserved in rock
– Glossopteris (glaw SAHP tuh ris) found in rocks in
Africa, S. America, Australia, India, &
Antarctica
– Mesosaurus & Lystrosaurus (fresh water
reptiles) found on different continents
Evidence from Climate…
• As continent moves toward equator,
climate becomes warmer
• As continent moves toward poles, climate
becomes colder
• Continents carry with it fossils and rocks
formed at old location
Evidence from Climate cont…
• Example…
– Fossils of tropical plants found on island in
Arctic Ocean
– Deep scratches in rocks show glaciers covered
S. Africa (too warm for this to happen today)
Wegener’s Hypothesis….
• Wegener suggested continents plowed
across ocean floors
• Wegener could not provide a satisfactory
explanation for the force that pushes or
pulls the continents
• Could not identify cause of continental
drift so…