TEKS 8C: Calculate percent composition and empirical and molecular formulas. Early People of the Americas

TEKS 8C: Calculate percent composition and empirical and molecular formulas. Understand how people may have first reached the Americas. Find out how farming led to civilizations. Explore the civilizations of the Mayas, Aztecs, and Incas. Objectives

TEKS 8C: Calculate percent composition and empirical and molecular formulas. Terms and People glacier – thick sheet of ice irrigate – to water crops by channeling water from rivers or streams surplus – excess; quantity that is left over civilization – an advanced culture in which people have developed cities, science, and industries

TEKS 8C: Calculate percent composition and empirical and molecular formulas. How did early civilizations develop in the Americas? Scientists have several theories about how people first came to the Americas. One theory says people migrated over a land bridge. Another theory says people came by boat.

TEKS 8C: Calculate percent composition and empirical and molecular formulas. Between 10,000 and 100,000 years ago, much of the world was covered by glaciers. As more of the world’s water froze, the level of the oceans dropped, and a land bridge appeared between Siberia and Alaska. Today, that land bridge lies under a narrow waterway called the Bering Strait.

TEKS 8C: Calculate percent composition and empirical and molecular formulas. Many scientists think people first came to North America between 20,000 and 30,000 years ago. They believe that hunters crossed the land bridge in pursuit of animals such as the woolly mammoth.

TEKS 8C: Calculate percent composition and empirical and molecular formulas. Over thousands of years, people spread across North and South America.

TEKS 8C: Calculate percent composition and empirical and molecular formulas. The coastal-route theory says that people crossed the arctic waters by boat and traveled southward along the Pacific coast. Many Native American groups dismiss both theories in favor of their own creation stories.

TEKS 8C: Calculate percent composition and empirical and molecular formulas. For centuries, early humans could fill most of their needs by hunting, but then many of the larger animals began to disappear. In many places, hunters became gatherers, traveling around and searching for wild plants and small game. hunters gatherers

TEKS 8C: Calculate percent composition and empirical and molecular formulas. About 8,000 years ago, gatherers in Mexico began growing food, including squash and lima beans. The discovery of farming meant that families no longer had to wander in search of food. Farmers began to irrigate crops and learned how to raise animals such as pigs, llamas, and cattle.

TEKS 8C: Calculate percent composition and empirical and molecular formulas. The population grew rapidly, and once they began to produce surplus food, Native Americans started trading with others. Some farming communities grew into cities, which became centers of government and religious life. With the development of cities came the beginnings of civilization.

TEKS 8C: Calculate percent composition and empirical and molecular formulas. Over the centuries, several civilizations rose and declined in the Americas: the Mayas the Aztecs the Incas

TEKS 8C: Calculate percent composition and empirical and molecular formulas. The Mayas Time PeriodBetween A.D. 250 and A.D. 900 LocationPresent-day Mexico and Central America AchievementsBuilt splendid cities Developed arts, a system of government, and a written language Created the most accurate calendar known until modern times

TEKS 8C: Calculate percent composition and empirical and molecular formulas. Around A.D. 900, the Mayas began to abandon their cities, perhaps because of disease or overpopulation.

TEKS 8C: Calculate percent composition and empirical and molecular formulas. The Aztecs Time PeriodBetween the 1300s and 1500s LocationPresent-day Mexico AchievementsBuilt the city Tenochtitlán, which may have been the biggest city in the world at the time Built Tenochtitlán on islands in a large lake and connected them by stone roadways

TEKS 8C: Calculate percent composition and empirical and molecular formulas. On a series of islands in a large lake, the Aztecs built a great capital city, Tenochtitlán, on the site of present-day Mexico City.

TEKS 8C: Calculate percent composition and empirical and molecular formulas. Tenochtitlán PopulationMore than 200,000 people lived there at the city’s height. FarmingMany farmers raised crops on floating platforms. ReligionReligion dominated Aztec life. The center of the city had dozens of temples that honored Aztec gods. The Aztecs practiced human sacrifice as an offering to their gods.

TEKS 8C: Calculate percent composition and empirical and molecular formulas. During the 1400s, Aztec armies brought half of modern-day Mexico under their control. The Aztecs were harsh rulers, and their subjects would eventually turn on them when Europeans came to conquer the region. Aztecs subjects Europeans

TEKS 8C: Calculate percent composition and empirical and molecular formulas. The Incas Time PeriodBetween the early 1400s and 1533 LocationDown the coast of South America along the Andes, across the Atacama desert, and to the fringes of the Amazon rain forest AchievementsBuilt the largest empire in the world in the 1400s Buildings of huge stones shaped to fit together Roads, walls, canals, and bridges Fine weavings and metalwork