This document summarizes Alfred Wegener's continental drift hypothesis from the early 20th century. It discusses how Wegener proposed that the continents were once joined together in a supercontinent called Pangaea, which later broke apart and drifted to their current positions. The document provides evidence that Wegener used to support his hypothesis, including the apparent fit of continental coastlines, fossil correlations between separated continents, and matching geological formations. However, Wegener's idea was controversial at the time because he could not explain the mechanism of continental motion. It was not until the development of plate tectonic theory that scientists fully accepted the concept of continental drift.

1. Chapter 14 Lesson 1 – The Continental Drift Hypothesis – p494-500 – page 1
New Vocabulary
oPangaea (495) – The supercontinent that all continents today were once a part of
oContinental Drift (495) – A hypothesis that suggests that continents are in constant motion on the surface of
Earth
Pangaea
oEach year, North America moves a few _____________________ farther away from Europe and closer to Asia.
oNearly 100 years ago, Alfred _________________ began an important investigation to know whether Earth’s
continents were fixed in their positions.
o He proposed that all continents were once part of a supercontinent called ____________.
o Over time Pangaea began_________________ __________________, and the continents slowly
moved to their present positions.
oWegener proposed the hypothesis of _____________________ drift, which suggested that continents are in
constant motion on the surface of Earth.

2. Chapter 14 Lesson 1 – The Continental Drift Hypothesis – p494-500 – page 2
Evidence That Continents Move
oThe most obvious evidence for continental drift is that the continents appear to fit together like pieces of a
__________________________.
oHowever, scientists were skeptical, and Wegener needed additional evidence
 Apparent fit of the continents
 Past ____________ Data
 __________________ Correlation
 _____________ and Mountain Correlation
Climate Clues

3. Chapter 14 Lesson 1 – The Continental Drift Hypothesis – p494-500 – page 3
oWhen Wegener pieced Pangaea together, he proposed that South America, Africa, India, and Australia were
located closer to ___________________________ 280 million years ago.
oHe suggested the climate of the Southern Hemisphere was much ______________________ at the time.
o Glaciers covered most of these continents
oWegener studied the _______________ deposited by glaciers in South America, Africa, India, and Australia.
oHe discovered ________________ _______________, or deep scratches in rocks made as the glaciers moved
across the land on neighboring continents today.

4. Chapter 14 Lesson 1 – The Continental Drift Hypothesis – p494-500 – page 4
Fossil Clues
oAnimals and plants that lived on different continents can be ____________________ to that continent alone.
o Kangaroos are exclusive to___________________ . Lions live in ________________but not S. America.
o Because ____________________ separate continents, these animals cannot travel from one continent
to another by natural means
oHowever, _______________________of similar organisms have been found on several continents separated by
oceans.
oFossils of a plant called Glossopteris have been discovered in rocks from South America, ______________,
India, Australia, and________________________.
oEvidence suggests these plants grew in a _____________________environment. Therefore, the climate of this
region, including Antarctica, was different than it is today.
o Antarctica had a warm and wet climate and changed drastically from _________ milllion years earlier
when glaciers existed.
Rock Clues

5. Chapter 14 Lesson 1 – The Continental Drift Hypothesis – p494-500 – page 5
oWegener also observed that ________________________ ranges and rock formations on different continents
had common origins.
 Today geologists have determined that large-scale volcanic eruptions occurred on the western coast of
_________________ and the eastern coast of South America at about the same time hundreds of millions of
years ago
o These volcanic rocks are identical in both ____________________and ___________
oThe _____________________ mountain range in northern Europe and the Appalachian Mountains in eastern
N. America are similar in age, structure, and composition.
oIf you place the continents ______________________, these mountains would meet and form on long,
continuous mountain belt.

6. Chapter 14 Lesson 1 – The Continental Drift Hypothesis – p494-500 – page 6
What is missing?
oWegener continued to support the continent drift hypothesis until his death in ______________
oHis ideas were not widely accepted until nearly 4 decades later, because he could not explain how they
________________.
oOne reason scientists questioned continental drift was because it is a ______________ process
oIt was not possible for Wegener to measure how ________________ the continents moved
o How could continents push their way through the ___________________rock of the sea floor?
o However at that time, the world was only beginning to understand what the seafloor looked like.
o It took many years after Wegener died before the evidence of plate tectonics hidden in the rifts on the
seafloor to be discovered.

7. Chapter 14 Lesson 1 – The Continental Drift Hypothesis – p494-500 – page 7