The First Americans
About 120,000 years ago, the Earth fell into an ice age.
The northern polar ice cap grew southward, water solidified into
ice, and ocean levels fell. With the lowering of the oceans, hidden
land was exposed, including a land bridge connecting Siberia (located
in modern-day eastern Russia) and Alaska. Between 15,000 and 50,000
years ago, various small, nomadic hunting groups from Asia crossed
the land bridge, becoming the first human inhabitants of the Americas.
Over the next millenia, these earliest Americans dispersed
across much of the Western Hemisphere. As the Ice Age came to an
end around 10,000 years ago and Earth’s atmosphere warmed, the land
that these groups inhabited changed dramatically. Sea levels rose and
melting glaciers filled the Great Lakes and Mississippi River Basin
with water. Glaciers receded northward, and frozen plains gave way
to deciduous eastern forests, grassy central plains, and
desert throughout the West. In time, the land bridge disappeared
back under the body of water now known as the Bering Strait.
The descendants of the earliest Americans changed with
the landscape. As Ice Age animals such as woolly mammoths disappeared,
hunters began to prey on smaller game. The groups also fished and
gathered local provisions, like seeds and nuts, from the land. About 5,000
years ago, some groups began to domesticate plants. As these groups
learned how to farm and more efficiently use natural resources,
they required less land, and many in the East and Midwest gave up
their nomadic lifestyle and established small, stable communities
by around 300 B.C.