ENVIRONMENT AND CULTURE IN ANCIENT AMERICA 13
ists have attempted to reconstruct the history of
Nuclear America. The framework for this effort is a
sequence of stages that are based on the technology,
social and political organization, religion, and art of
a given period. To this sequence of stages special-
ists commonly assign the names Archaic, Formative
or Preclassic, Classic, and Postclassic. This scheme is
tentative in detail, with much chronological over-
lap between stages and considerable variation in
the duration of some periods from area to area.
TheArchaic stage began about nine thousand
years ago when a gradual shift from food gathering
and hunting to agriculture began in many parts of
Nuclear America. This incipient agriculture, how-
ever, did not cause revolutionary changes in these
societies. For thousands of years, people continued to
live in much the same primitive fashion as before. So-
cial groups were small and probably seminomadic.
Weaving was unknown, but simple pottery appeared
in some areas toward the end of the period.
Between 2500 and 1500 BCE, a major cultural
advance in various regions of Nuclear America
opened the Formative, or Preclassic, period. Centu-
ries of haphazard experimentation with plants led
to the selection of improved, high-yield varieties.
These advances ultimately produced an economy
solidly based on agriculture and sedentary village
life. Maize and other important domesticated plants
were brought under careful cultivation; irrigation
came into use in some areas; and a few animals
were domesticated. By the end of the period, pottery
and weaving were highly developed. Increased food
production enabled villagers to support a class of
priests who acted as intermediaries between people
and gods. More abundant food also released labor
for the construction of ceremonial sites—mounds
of earth topped by temples of wood or thatch.
The social unit of the Formative period was a
village community that was composed of one or
more kinship groups, but by the end of the period,
small chiefdoms that united several villages devel-
oped. Because land and food were relatively plenti-
ful and populations were small, warfare must have
been infrequent. Religion centered on the worship
of water and fertility gods; human sacrifi ce was
probably absent or rare.
The advances of the Formative period culmi-
nated in the Classic period, which began around
the opening of the Christian era and lasted until
approximately 1000 CE. The term Classic refers to
the fl owering of material, intellectual, and artistic
culture that marked this stage. No basic changes in
technology took place, but the extension of irriga-
tion works in some areas caused increases in food
production and freed manpower for construction
and technical tasks. Population also increased,
and in some regions, genuine cities arose. Archi-
tecture, pottery, and weaving reached an impres-
sive level of style. Metallurgy fl ourished in Peru,
as did astronomy, mathematics, and writing in
Mesoamerica (central and south Mexico and ad-
jacent upper Central America). The earlier earth
mounds gave way to huge stone-faced pyramids,
elaborately ornamented and topped by great tem-
ples. The construction of palaces and other offi cial
buildings nearby made each ceremonial center the
administrative capital of a state ruled by a priest-
king. Social stratifi cation was already well devel-
oped, with the priesthood the main ruling class.
However, the growing incidence of warfare in the
late Classic period (perhaps caused by population
pressure, with greater competition for land and
water) brought more recognition and rewards to
successful warriors. Religion became an elaborate
polytheism served by a large class of priests.
Typical cultures of the Classic period were the
Teotihuacán civilization of central Mexico, the
Monte Albán culture in southwestern Mexico, and
the lowland Maya culture of southern Yucatán and
northern Guatemala. The Olmec civilization of the
Mexican gulf lowlands displays some Classic fea-
tures but falls within the time span usually allotted
to the Formative. In Peru the period is best repre-
sented by the brilliant Mochica and Nazca civiliza-
tions of the coast. The available evidence suggests
that the Classic stage was limited to Mesoamerica,
the central Andean area (the highlands and coasts
of Peru and Bolivia), and the Ecuadorian coast.
The Classic era ended abruptly in both the
northern and southern ends of Nuclear America.
Shortly before or after 1000 CE, most of the great
Classic centers in Mesoamerica and Peru were
abandoned or destroyed by civil war or foreign
invasion. Almost certainly, the fall of these civi-
lizations came as the climax of a longer period of
decline. Population pressure, soil erosion, and