1) What are the lines of evidence that Alfred Wegener used to support the idea of continental
drift? Why did scientists of his day doubt that continents drifted?
Bloom’s Taxonomy: Remembering/Understanding
Section: 2.1 What Evidence Supports Continental Drift?
Essent’l Concept: 2.1 Evaluate the evidence that supports continental drift
2) Briefly discuss four important lines of evidence that support the hypothesis of continental
drift.
Bloom’s Taxonomy: Remembering/Understanding
Section: 2.1 What Evidence Supports Continental Drift?
Essent’l Concept: 2.1 Evaluate the evidence that supports continental drift
31
3) Discuss changes in the lithosphere that occur between an oceanic ridge and an oceanic trench.
Answer: The mid-ocean ridge is a continuous underwater mountain range that winds through
every ocean basin in the world. It is entirely volcanic in origin, wraps one-and-a-half times
around the globe, and rises more than 2.5 kilometers (1.5 miles) above the surrounding deep-
ocean floor. New ocean floor forms at the crest, or axis, of the mid-ocean ridge. By the process
of sea floor spreading, new ocean floor is split in two and carried away from the axis, replaced
by the upwelling of volcanic material that fills the void with new strips of sea floor. Sea floor
spreading occurs along the axis of the mid-ocean ridge, which is referred to as a spreading center.
At the same time, ocean floor is being destroyed at deep ocean trenches. Trenches are the deepest
parts of the ocean floor and, on a map of the sea floor, resemble a narrow crease or trough. The
largest earthquakes in the world occur near these trenches; they are caused by a plate bending
downward and slowly plunging back into Earth’s interior. This process is called subduction, and
the sloping area from the trench along the downward-moving plate is called a subduction zone.
Diff: 2
Bloom’s Taxonomy: Remembering/Understanding
Section: 2.3 What Features Occur at Plate Boundaries?
Essent’l Concept: 2.3 Discuss the origin and characteristics of features that occur at plate
boundaries
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2.4 Visual Questions
1)
How is the age of the ocean sediments related to the distance from a mid-ocean ridge?
Bloom’s Taxonomy: Remembering/Understanding
Section: 2.2 What Evidence Supports Plate Tectonics?
Essent’l Concept: 2.2 Summarize the evidence that supports plate tectonics
Global Sci Out: 7
33
2)
Why does a map of worldwide earthquakes closely match the locations of worldwide plate
boundaries?
34
Bloom’s Taxonomy: Applying/Analyzing
Section: 2.2 What Evidence Supports Plate Tectonics?
Essent’l Concept: 2.2 Summarize the evidence that supports plate tectonics
Global Sci Out: 7
35
3)
How are convergent and divergent plate boundaries related to constructive and destructive
plate margins?
Bloom’s Taxonomy: Applying/Analyzing
Section: 2.3 What Features Occur at Plate Boundaries?
Essent’l Concept: 2.3 Discuss the origin and characteristics of features that occur at plate
boundaries
36
4)
How can plate tectonics be used to help explain the differences between a seamount and a
tablemount?
Bloom’s Taxonomy: Applying/Analyzing
Section: 2.4 Testing the Model: What Are Some Applications of Plate Tectonics?
Essent’l Concept: 2.4 Show how plate tectonics can be used as a working model
37
5)
How has seismic activity been used in our understanding of plate boundaries?
Bloom’s Taxonomy: Applying/Analyzing
Section: 2.2 What Evidence Supports Plate Tectonics?
Essent’l Concept: 2.2 Summarize the evidence that supports plate tectonics
Global Sci Out: 7
38
6)
How does convection in the asthenosphere explain ocean basin features, heat flow, and the
thickness of the lithosphere?
Bloom’s Taxonomy: Applying/Analyzing
Section: 2.2 What Evidence Supports Plate Tectonics?
Essent’l Concept: 2.2 Summarize the evidence that supports plate tectonics
Global Sci Out: 7
39
7)
Describe the formation of the magnetic patterns in rocks on the seafloor.
Bloom’s Taxonomy: Remembering/Understanding
Section: 2.2 What Evidence Supports Plate Tectonics?
Essent’l Concept: 2.2 Summarize the evidence that supports plate tectonics
Global Sci Out: 7
40