Question

Heory of Plate Tectonics

Students will understand that internal and external sources of energy have
ered the features of the Earth by means of both constructive and destructive forces.
With no major errors or omissions in the 3.0 or 2.0 objectives, the student can...
1. Explain what caused the theory of continental drift to be modified to
the theory of plate tectonics. (Be sure to include why the theory was
changed... what happened?)
;
2. Identify 4 pieces of evidence that support the theories of continental
drift and plate tectonics.
3. Describe the difference between a scientific law and a scientific theory.
4. Identify the reason that Wegener's theory of continental drift was not
accepted by other scientists.
5. Compare and contrast the theory of continental drift to the theory of
plate tectonics.
6. Define: seafloor spreading, continental drift, subduction zone, and
mid-ocean ridge.

Answer 1

This detailed answer covers the theory modification from continental drift to plate tectonics, evidence supporting both theories, the difference between scientific laws and theories, the rejection of Wegener's theory, a comparison of continental drift and plate tectonics, and the definition of key terms in geology.

Step-by-step explanation:

1. Explanation of Theory Modification:

The theory of continental drift, proposed by Alfred Wegener, suggested that the continents were once all connected in a supercontinent called Pangaea. However, this theory did not have a mechanism to explain how the continents moved. The theory of plate tectonics, developed in the 1960s, integrated the concept of continental drift with the understanding of the Earth's lithosphere being divided into plates that move due to convection currents in the underlying asthenosphere.

2. Evidence for Continental Drift and Plate Tectonics:

Four pieces of evidence supporting these theories are:

1. Fossil distribution: Similar plant and animal fossils found on different continents that were once connected.
2. Rock and mountain formations: Matching rock types and mountain ranges across continents.
3. Seafloor spreading: The age of oceanic crust increasing as you move away from mid-ocean ridges.
4. Earthquake and volcano distribution: Concentration along plate boundaries.

3. Difference between Scientific Law and Scientific Theory:

A scientific law describes a phenomenon or pattern that has been consistently observed and can be mathematically expressed. On the other hand, a scientific theory is a well-substantiated explanation of some aspect of the natural world that is based on a body of evidence.

4. Reason for Rejection of Wegener's Theory:

Wegener's theory of continental drift faced rejection because he couldn't provide a satisfactory mechanism for how continents could move across the Earth's surface.

5. Comparison of Continental Drift and Plate Tectonics:

Continential drift suggests that the continents move across the Earth's surface, while plate tectonics involves the movement of lithospheric plates due to convection currents in the asthenosphere. The theory of plate tectonics provides the mechanism that was missing from Wegener's continental drift theory.

6. Definitions:

• Seafloor spreading: The process through which new oceanic crust is formed at mid-ocean ridges and spreads outward.
• Continental drift: The hypothesis that the continents were once connected in a supercontinent and have since moved apart.
• Subduction zone: A region where one lithospheric plate is forced beneath another into the Earth's mantle.
• Mid-ocean ridge: An underwater mountain range formed by seafloor spreading.

Learn more about Plate Tectonics