Key Concept Summary
Interactive Concept Map
Chapter Review
Standardized Test Practice
The theory of plate
tectonics states that
Earth’s lithosphere is
broken up into rigid
plates that move over
Earth’s surface.
Lesson 1: The Continental Drift
Hypothesis
• The puzzle piece fit of
continents, fossil evidence,
climate, rocks, and mountain
ranges supports the
hypothesis of continental
drift.
• Scientists were skeptical of
continental drift because
Wegener could not explain
the mechanism for
movement.
Lesson 2: Development of a Theory
• Seafloor spreading provides a mechanism for
continental drift.
• Seafloor spreading occurs at mid-ocean ridges.
• Evidence of magnetic reversal in rock, thermal
energy trends, and
the discovery of
seafloor spreading
all contributed to
the development
of the theory of
plate tectonics.
Lesson 3: The Theory of Plate
Tectonics
• Types of plate boundaries, the location of
earthquakes, volcanoes, and mountain ranges, and
satellite measurement of plate motion support the
theory of plate tectonics.
• Mantle convection, ridge
push, and slab pull are
the forces that cause
plate motion. Radioactivity
in the mantle and thermal
energy from the core
produce the energy for
convection.
Which of these have been found on
several continents separated by
oceans, suggesting that they were
once geographically closer together?
A. animals
B. ice sheets
C. plant fossils
D. plate boundaries
Which of these refers to the process
by which new oceanic crust forms
along a mid-ocean ridge as older
oceanic crust moves away from the
ridge?
A. continental drift
B. plate tectonics
C. seafloor spreading
D. magnetic reversal
What is the rigid outermost layer
of Earth called?
A. mantle
B. lithosphere
C. plate
D. transform plate boundary
What forms where two plates
slide past each other?
A. transform plate boundary
B. divergent plate boundary
C. convergent plate boundary
D. semiplastic mantle
What is the process in which a
denser plate sinks below a more
buoyant plate?
A. seafloor spreading
B. convergence
C. convection
D. subduction
What is the name of the
supercontinent that all continents
were once part of?
A. Wegener
B. Pangaea
C. mantle
D. seafloor
Where did scientists find glacial
features that are usually
associated with cooler climates?
A. Antarctica
B. plate boundaries
C. mountain ranges
D. Africa
Which term refers to vast
mountain ranges on the seafloor?
A. volcanoes
B. oceanic crust
C. pillow lava
D. mid-ocean ridges
Which of these states that Earth’s
surface is made of rigid slabs of rock
that move with respect to one another?
A. the theory of plate tectonics
B. the theory of mid-ocean ridges
C. the theory of divergent plate
boundaries
D. the theory of transform plate
boundaries
What is the name for the force
that pulls on the rest of a plate as
part of a dense plate sinks?
A. ridge push
B. basal drag
C. slab pull
D. plate tectonics