Grade 4 Social Studies
Unit 1 Content Notes
The Land Bridge Theory
The Land Bridge Theory is the idea that Native Americans
migrated from Asia to North America during the Ice Age. To migrate
is to move from one place to another. They then continued across
North America and spread into South America. During the Ice Age,
there were very low temperatures. This caused large areas of water
on the earth to freeze. Glaciers, large blocks of ice, were formed.
The glaciers caused the level of water in the ocean to drop. When
the water level dropped, land that was under water became
uncovered.
Some people
think that huntergatherer people
may have crossed
this land bridge to
follow herds of
animals.
1. Explain the land
bridge theory in
your own words.
2. Looking at the
map why do you
think the Native
American
population
migrated in the
directions that they
did?
Cherokee County Schools
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