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Continental Drift Study Questions (5-3) pages 136 - 140
1. How has Earth’s surface changed in the past 300 million years? Did that change happen quickly or
slowly?
Earth’s surface has changed a great deal through the drifting of continents coming
together and moving apart.
These changes occur slowly while others, such as earthquakes and volcanoes, can happen in
a very short amount of time.
2. What theory relates to changes over time of Earth’s surface?
The theory of continental drift deals with changes to Earth’s surface over time. It states
that all of the continents were once joined together in a single landmass and have since drifted
apart over time.
3. Who proposed the theory? When was it proposed?
Alfred Wegener proposed the theory of continental drift in 1915.
4. What four types of evidence were used to support it? Describe them.
Four types of evidence that support this theory include the shapes of the continents,
similar land features on different continents, similar fossils found on different continents, and
evidence from climate changes.
1. Shapes of the continents - The continents fit together like pieces of a jigsaw puzzle. For
example, the east coast of South America fits into the southwest coast of Africa.
2. Land features evidence - Similar rocks that make up mountain chains line up even though they
are on two different continents, separated by an ocean. Also, mountain ranges are usually located
along or parallel to the edges of continents. Coals beds in Europe and South and North America
also lined up when Pangaea was together.
3. Fossil evidence - Fossils of organisms have been found on two continents separated by an
ocean, but those organisms were not able to travel across the ocean.
4. Climate evidence – Evidence of glacier erosion (scratches on rocks) has been found in places
that are now warm. Also, coal deposits were found in Antarctica and the Artic even though they
formed in a tropical climate.
5. Why did other scientists not support it at the time it was proposed?
It was not supported because the theory did not explain what forces moved the continents
around. Also, scientists believed in the Contraction Theory to explain Earth’s land features.
We now know that it is the heat from Earth’s interior convecting in the mantle that drives plate
tectonics.
6. Deposits of coal have been found beneath the ice of Antarctica. But coal only forms in warm
swamps. Use Wegener’s hypothesis to explain how coal could be found so near to the South Pole.
If continents drifted across the surface of Earth, then climates would have changed over
time as they moved nearer the poles or near the equator.
Coal could have formed in Antarctica when that continent was located in a more tropical
region of Earth near the equator. After its formation, it then would have drifted nearer to the
South Pole.