This Fleeting World

Acceleration: The Agrarian Era 25
the human impact on the natural environment and also on the cultures
and lifeways of humans themselves. Agriculturalists manipulated plant and
animal species so intensely that they began to alter the genetic makeup
of prey species in a process commonly referred to as “domestication.” By
clearing forests, diverting rivers, terracing hillsides, and plowing the land,
agriculturalists created landscapes that were increasingly anthropogenic
(shaped by human activity).
Finally, by altering their own lifeways, agriculturalists created new
types of communities, radically different in scale and complexity from
those of the era of foragers. Humans did not domesticate just other species;
they also domesticated themselves.
Agriculture does not automatically increase the biological productivity
of the land. Indeed, agriculturalists often reduce total productivity by
removing the many species for which they have no use. They increase the
productivity only of those plants and animals that they find most useful.
Removing undesired plants leaves more nutrients, sunlight, and water for
domesticated crops such as corn, wheat, or rice, while killing wolves and
foxes allows cattle, sheep, and chickens to flourish in safety. By increasing
the productivity of favored prey species, humans could feed more of
themselves from a given area than would have been possible using foraging
technologies.
Whereas technological change during the era of foragers was extensive
(it allowed humans to multiply by increasing their range), technological
change during the agrarian era was intensive (it allowed more humans
to live within a given range). As a result, humans and their domesticates
began to settle in larger and denser communities; as they did so they
transformed their ecological and social environments. The result was a
revolution in the pace and nature of historical change.
Earliest Evidence of Agriculture
Dates for the earliest evidence of agriculture remain subject to revision.
At present the earliest clear evidence comes from the corridor between the
Nile Valley and Mesopotamia that links Africa and Eurasia. In the Fertile
Crescent (the arc of highlands around the great rivers of Mesopotamia)
grain crops were cultivated from about 8000 bce (ten thousand years ago).
In the Sahara Desert west of the Nile River, in lands that then were much
less arid than they are today, communities may have domesticated cattle as