Page 304 - Earth's Climate Past and Future
P. 304
280 PART V • Historical and Future Climate Change
IN SUMMARY, the overall outline of human evolution
has gradually fallen into place, but the sparse fossil
record makes it difficult to test hypotheses about
the cause or causes of human evolution. As a result,
the degree to which climate has affected human
evolution is unknown.
The Impact of Climate on Early Farming
In almost 2.5 million years, hominins had moved only
slightly beyond the most primitive level of Stone Age life,
adding control of fire and gradually more sophisticated
stone tools to a meager repertoire of skills. But once our FIGURE 15-10 Early human buildings Humans living in
species appeared, near 200,000 to 150,000 years ago, the northern Asia during the last glaciation constructed domed
pace of change quickened. By the time of the most recent dwellings of hides draped over mammoth bones. Other bones
glaciation, our ancestors painted amazingly lifelike por- served as anchors.
trayals of animals on the walls of caves and rock shelters
(Figure 15–9). They also made small statues of human
and animal figures and created jewelry by stringing and colder near-Arctic latitudes. There they built dome-
together shells, and they buried their dead with food and shaped houses with large mastodon bones supporting
possessions for use in a future life. In these changes, we the superstructure and animal hides draping the roof
can recognize the early origins of a true human “culture.” for protection from rain and snow (Figure 15–10).
More sophisticated stone tools designed for specific People also learned how to make rope from naturally
functions also appeared, and, for the first time, people available fibers and used the rope to make snares and
began to use bone, a much more “workable” substance lines and nets to catch small animals, birds, and fish. The
than stone, yet hard enough for many uses: as needles, hunting-gathering life became a hunting-gathering-
awls (hole-punchers), and engraving tools. Needles fishing life. People shaped bone into spear throwers that
made possible sewn clothing that fit closely, rather than held stone spear points and used rope to help bind the
loosely draped animal hides. With greater protection spear points to the shafts. This new technology pro-
from the elements, people pushed northward into higher duced a lethal and revolutionary new way of hunting
that combined a weapon that could kill efficiently with a
hand that could grasp it and an arm with the natural
range of motion to throw it. Hunters could now bring
down larger game—even mammoths—from a safer dis-
tance, as cave paintings show. By the start of the present
interglaciation, an explosive alteration of basic human
existence was underway.
15-4 Did Deglacial Warming Lead to Early
Agriculture?
The first evidence of agriculture dates to just over
12,000 calendar years ago in a region of the Middle East
called the Fertile Crescent, encompassing present-day
Syria, Iraq, Jordan, and Turkey. The people living in
this region (called Natufians) abandoned the hunting-
and-gathering way of life and began to cultivate wheat,
rye, barley, peas, and lentils rather than harvesting
grains growing in the wild. Because agriculture elimi-
FIGURE 15-9 Cave painting of the glacial era Despite the nated the need for seasonal migrations to search for
harsh glacial climate, our ancestors left beautiful, almost food, these people took up residence in permanent
modern-looking paintings on the walls of caves in southern dwellings. Within 1000 years, the dwellings began to
Europe. (Ferrero/Labat/Auscape International.) cluster into permanent village settlements.