Transcript File - Ms. D. Science CGPA

Plate Tectonics
Table of Contents
Drifting Continents
Ms. De Los Rios
7th Grade
Vocabulary 5.1
1. Continental Drift- the hypothesis that the continents slowly
move across Earth’s surface.
2. Pangaea- The name of the single landmass that began to
break apart 200 million years ago and gave rise to today’s
continents.
3. Fossil- Preserved remains or traces of an organism that
lived in the past.
Pangaea means “all lands” in Greek.
Alfred Wegener
(November 1, 1880 – November 1930)
Early life and education
•On November 1, 1880, Alfred Wegener was born in Berlin as the youngest of five
children in a clergyman's family.
•He graduated as the best in his class. Afterward he studied Physics, meteorology
and Astronomy in Berlin.
•He was a German polar researcher, geophysicist and meteorologist.
•During his lifetime he was primarily known for his achievements in meteorology
and as a pioneer of polar research, but today he is most remembered for
advancing the theory of continental drift (Kontinentalverschiebung) in 1912, which
hypothesized that the continents were slowly drifting around the Earth.
• His hypothesis was controversial and not widely accepted until the 1950s, when
numerous discoveries such as palaeomagnetism (the study of the record of the
Earth's magnetic field in rocks) provided strong support for continental drift, and
thereby a substantial basis for today's model of Plate tectonics.
What Was Wegener’s Hypothesis About the
Continents?
In 1910, a German scientist named Alfred Wegener
became curious about why some continents look as
though they could fit together.
Wegener’s hypothesis was:
that all the continents were once joined
together in a single landmass and have
since drifted apart.
Wegener’s idea that the continents moved
over Earth’s surface became known as
continental drift.
What Was Wegener’s Hypothesis About the
Continents?
According to Wegener:
•The continents were joined together in a
supercontinent, or single landmass
about 300 million years ago.
• Wegener called the supercontinent
Pangaea.
•Over tens of millions of years, Pangaea
began to break apart.
•The pieces of Pangaea slowly moved
toward their present-day locations.
•These pieces became the continents as
formed today.
Wegener’s Book
In 1951, Wegener published his
evidence for continental drift in a
book called The Origin of
Continents and Oceans.
Drifting Continents pg. 173 Fig. 1
Piecing It All Together
The coastlines of some
continents seem to fit
together like a jigsaw
puzzle.
1. Draw an arrow to
match the numbered
coast with the lettered
coast that seems to fit.
2. How would a
continent’s climate
change if it drifted closer
to the equator?
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Wegener’s 3 Pieces of Evidence
1. Land features
2. Fossils
3. Climate change
Evidence #1 From Land Features pg. 173
Land features on the continents such
as mountain ranges and coal fields
provided Wegener with evidence for his
hypothesis.
He pieced together maps of Africa
and South America.
• He noticed how the coal fields lined up.
•He also noticed that coal fields in
Europe and North America also match
up.
Evidence From Fossils pg. 174
Wegener also used fossils to
support his hypothesis for
continental drift.
•A fossil is any trace of an ancient
organism that has been preserved in rock.
•Plant fossils such as Glossopteris
(fernlike plant) found in various continents
Africa, South America, Australia, India, and
Antarctica.
•Freshwater reptiles such as Mesosaurus
and Lystrosaurus found in places that are
now separated by oceans (reptiles that
could not swim long distances)
Drifting Continents
Fig. 2 Pg. 174
Pangaea and
Continental Drift
Many types of
evidence suggest that
Earth’s landmasses
were once joined
together.
Glossopteris
Mesosaurus
Evidence #3 From Climate pg. 175
Wegener also used evidence of climate
change to support his hypothesis.
•As continents move towards the equator=
climates warmer as they move towards the
Poles= Colder.
•As continents moves, they carry along fossils
and rocks formed at all its previous locations.
Wegener’s Hypothesis Rejected
Wegener could not provide a satisfactory
explanation for the force that pushes or pulls
the continents. Because he could not identify
the cause of continental drift, most geologists
of his time rejected his idea.
Apply it! & Assess your Understanding
RESOURCES
Online activity
Rock Activity BBC
Brainpop Plate Tectonics