Continental Drift
Lesson in Earth Science
Mr. Fluharty
Pangaea
Ever since the development of accurate maps of the continents, a few people
speculated that the continents were once just one large land mass called Pangaea.
This idea was based on the shape of the continents and how they could be put
together like the pieces of a puzzle.
Alfred Wegener
Alfred Wegener (1880-1930) was a German scientist who weaved
together seemingly dissimilar, unrelated facts into a theory,
which was remarkably visionary for the time.
Wegener's scientific vision sharpened in 1914 as he was
recuperating in a military hospital from an injury suffered as a
German soldier during World War I. Like others before him,
Wegener had been struck by the remarkable fit of the coastlines
of South America and Africa. But, unlike the others, to support his
theory Wegener sought out many other lines of geologic and
paleontologic evidence, such as the location of fossils and rock
layers on different continents.
Over geological time, Pangea split apart and parts of it moved
away to form today’s continents. Today, this idea is called
continental (kon-ti-NEN-tul) drift.
“Drift” refers to the idea that the continents slowly moved away
from each other, or drifted apart.
Continental
Drift Simulation
Continental
Drift Simulation
Procedure
1. Individually, carefully read each statement on the
worksheet, “Analyzing Evidence: Continental Drift.”
2. On the left side of the worksheet mark whether you think
the statement is or is not evidence.
3. Cross out each statement that you have decided was not
evidence. You will no longer consider these statements.
4. Now, using only the statements that are evidence, on the
right side, mark whether you think each piece of evidence
does or does not support the idea that continents have
moved.
5. With your group, discuss:
•
•
whether you identified a statement as evidence or not.
how each statement you checked as evidence either supports
or contradicts the idea of continental movement.
•
Statement 1 supports the idea that continents moved
because it shows that the same kind of plant was found in
different parts of the world. Since plants can’t move, one
explanation is that these different parts of the world were
once connected. (Note that the unlikelihood of the seeds
of the Glossopteris plant being distributed by wind or
water should have come up in the follow-up discussion of
the previous activity.)
•
Statement 2 supports the idea that the continents have
moved, because it helps explain why places with warm
climates today could have had cold climates in the past. It
also proposes the formation of a single large ice sheet at
that time rather than several different ice sheets.
•
Statement 5 supports the idea that continents have moved
because it shows a pattern of geological features in line
with the suggested single land mass.
•
Statement 6 supports the idea that continents have moved
because it is highly unlikely that rock layers in two different parts
of the world, affected by different forces, formed exactly the same
sequence of layers and fossils if they had not been joined.
Statement
•
Statement 8 supports the idea that continents have moved
because it shows how precisely two of the continents could have
once been attached. (If they were not attached, how could they fit
so well?)
•
Statement 9 supports the idea that continents have moved
because it shows that the continents are now moving. This means
that they could have moved in the past. Over billions of years, a
few centimeters per year could result in a distance of thousands of
kilometers.
•
Statement 10 supports the idea that continents have moved
because it shows the same worm fossil in different parts of the
world. One explanation for finding the same worm fossil in places
that are so far apart and have such different climates today is that
these areas were connected and had the same climate.
Fossils Found on Different Continents
(that could not swim)
• Glossopteris: a fern found on the southern continents: South
America, Africa, Asia (India and Madagascar only),
Antarctica, and Australia.
• Cynognathus: a land reptile found in South America and
Africa
• Lystrosaurus: a land reptile found in Africa, Antarctica, India,
and Madagascar
• Mesosaurus: a freshwater swimming reptile found in
southern Africa and South America