Unit Summary

One important environmental factor was the separation of the Americas and Afro-Eurasia after 15,000 BCE. As a result, different ecosystems developed in the Americas than in Afro-Eurasia. The Americas had no beasts of burden; corn was the major staple rather than rice or wheat. A second environmental factor is the sheer size and variety of habitats in the Americas. The north-south axis of the Americas extends nearly 11,000 miles, from the frigid Arctic rim to the equatorial rain forests of the Amazon River basin to Tierra Del Fuego at the southern tip of South America. A mountain spine runs nearly the entire length, and divides the Americas longitudinally, separating narrow coastal plains on the Pacific from broad plains on the eastern side that stretch toward the Atlantic. Several great river systems, especially the Mississippi and the Amazon, have been channels of human communication since ancient times. Thousands of different cultures, speaking many different languages and following different customs, lived on the two continents. Their ways of life varied from gathering and hunting to agrarian-urban states.

Agriculture developed independently in Mesoamerica and the Andean highlands after 3000 BCE. Farming and village settlement spread through those regions and by the second millennium BCE, the Olmec civilization appeared in Mesoamerica and the Chávin civilization in the central Andes. Unlike the land between the Euphrates and Tigris Rivers, the Nile River Valley, the Huang He (Yellow) River valley, or the Indus River Valley , these civilizations did not develop along great rivers. The catalyst for developing the Olmec civilization may have been surplus farming produce, population growth, or increasing trade. Connected by exchange of crops and products from the ocean, the lowlands, the highlands, and the rainforest, the Chávin civilization extended across the high Andes range to the lowlands on either side. After the Olmec and Chavín fell, other civilizations took their place or grew up nearby. The Maya, Aztec, and Inca Empires built on the culture and accomplishments of two thousand years of previous civilizations.

Between about 200 to 900 CE, the Maya region of southern Mexico, Guatemala, and Belize had more than fifty independent city-states. Although the Maya built on a basis of civilizations before them, the Maya city-states as well as the city-states of other contemporary cultures in Mesoamerica built larger and grander buildings, developed advanced writing, mathematics and astronomy, and had a more hierarchical and wealthy society. Two factors that gave the Maya power were rich agriculture and widespread trade. Among the largest cities were Tikal in Guatemala and Calakmul in Mexico. Maya societies produced monumental architecture, astronomic observatories, a phonetic writing system that yielded libraries of thousands of books, and a sophisticated calendar system based on a fifty-two-year cycle. These innovations would have given the Maya society strong cultural power, because many neighboring people would have been impressed. Mathematical systems that developed in Afroeurasia are comparable to Maya mathematics, which utilized positional notation, the concept of zero, and a base-20 numerical system. The monarchs and aristocratic families who ruled these city-states kept order and defended their lands in wars with other city-states. They also performed elaborate religious rituals to conciliate the gods who, Mayans believed, commanded the rain and sun. These rituals included blood-letting by members of the elite and royal families. The elites drew blood from their own bodies to offer to the gods. The Maya also sacrificed enemies captured in battle (instead of killing them on the battlefield). Farmers, artisans, and hunters paid taxes and supplied labor for construction of public temples, palaces, and ceremonial ball courts. After about 750 CE, the Maya area experienced a period of intensified warfare among city-states, monumental construction diminished, and many Maya cities were abandoned while new ones emerged as new centers of power . Deforestation, erosion, and drought may have contributed to the period of turmoil .

The Aztec Empire emerged in the fifteenth century. The Aztecs, a people who originally migrated from northern Mexico, owed a strong cultural debt to the Maya, Teotihuacán, and the Toltec cities in Mesoamerica. The Aztecs won their power by warfare. They unified much of central Mexico by defeating all other powerful cities and states. They created a state based on ingenious methods of farming, collection of tribute from conquered peoples, and an extensive network of markets and trade routes. The Aztec practiced ritual sacrifice of war captives (instead of killing them on the battlefield), but to a greater extent than the Maya had. The Aztecs believed that the god of the sun would stop shining and the universe would collapse without a constant supply of human hearts and blood. Tenochtitlán, an Aztec city was built on an island in Lake Texcoco, with three causeways linking it to the mainland. The city was built in circles, with temples and government buildings in an inner square, houses in the outer circles, and floating garden beds on the lake around the city. It was one of the largest cities in the world at that time. Its markets contained vast amounts of a variety of goods from all over Mesoamerica. Ultimately, the resentment of conquered people made the Aztec Empire unstable.

Like the Aztecs, the Incas built on a series of earlier civilizations, but combined cities and states together into a larger empire than any before in that region. The Inca rulers built a highly centralized political system that included methods of food distribution in times of poor harvests. They also created a network of about 25,000 miles of government-controlled roads that ran along the Andes spine and served military, administrative, and commercial purposes. The Incas did rely on military power but they also offered important social benefits to the population. In contrast to the Maya, the Incas did not have a writing system, but they used Andean quipus (sometimes spelled khipus), or sets of colored and knotted strings, to keep complex records.