THE AGRICULTURAL REVOLUTIONS

● Around 10,000 years ago humans began to cultivate plants, selecting for those with the highest nutritional yield, and to domesticate animals. These Agricultural Revolutions arose in various parts of the world.
● Climate change at the end of the last Ice Age is probably the major reason for the switch from food gathering to food production.
● Agriculturalists gradually spread across much of the planet. In certain environments pastoralism, the dependence of people on herd animals, prevailed.
● The more secure food supply made possible by agriculture led to a great increase in human population.

For most of human existence people ate only wild plants and animals. But around 10,000 years ago global climate changes seem to have induced some societies to enhance their food supplies with domesticated plants and animals. More and more people became food producers over the following millennia.
Although hunting and gathering did not disappear, this transition from foraging to food production was one of the great turning points in history because it fostered a rapid increase in population and greatly altered humans’ relationship to nature. Because agriculture arose in combination with new kinds of stone tools, archaeologists called the period the “Neolithic” and the rise of agriculture the “Neolithic Revolution.”
But that name can be misleading: first, stone tools were not its essential component, and second, it was not a single event but a series of separate transformations in different parts of the world. A better term is Agricultural Revolutions, which emphasizes that the central change was in food production and that agriculture arose independently in many places. In most cases agriculture included the domestication of animals as well as the cultivation of new food crops.

The Transition to Plant Cultivation

Food gathering gave way to food production in stages spread over hundreds of generations. The process may have begun when forager bands, returning year after year to the same seasonal camps, deliberately scattered the seeds of desirable plants in locations where they would thrive and discouraged the growth of competing plants by clearing them away. Such semicultivation could have supplemented food gathering for many generations. Eventually, families choosing to concentrate on food production would have settled permanently near their fields.
The presence of new, specialized tools for agriculture first alerted archaeologists to the beginning of a food production revolution. These included polished stone heads to work the soil, sharp stone chips embedded in bone or wooden handles to cut grain, and stone mortars to pulverize grain. Since stone axes were not very efficient for clearing away shrubs and trees, farmers used fire to get rid of unwanted undergrowth (the ashes were a natural fertilizer).
The transition to agriculture occurred first in the Middle East. By 8000 b.c.e. humans, by selecting the highest-yielding strains, had transformed certain wild grasses into the domesticated grains now known as emmer wheat and barley. They also discovered that alternating the cultivation of grains and pulses (plants yielding edible seeds such as lentils and peas) helped maintain soil fertility. Women, the principal gatherers of wild plant foods, probably played a major role in this transition to plant cultivation, but the heavy work of clearing the fields would have fallen to men.
Plants domesticated in the Middle East spread to Greece as early as 6000 b.c.e., to the lightsoiled plains of Central Europe and along the Danube River shortly after 4000 b.c.e., and then to other parts of Europe over the next millennium. Early farmers in Europe and elsewhere practiced shifting cultivation, also known as swidden agriculture. After a few growing seasons, the fields were left fallow (abandoned to natural vegetation) for a time to restore their fertility, and new fields were cleared nearby. From around 2600 b.c.e. people in Central Europe began using ox-drawn wooden plows to till heavier and richer soils.
Wheat and barley could not spread farther south because the rainfall patterns in most of Africa were unsuited to their growth. Instead, separate Agricultural Revolutions took place in Saharan and sub-Saharan Africa, beginning almost as early as in the Middle East. During a particularly wet period after 8000 b.c.e., people in what is now the eastern Sahara began to cultivate sorghum, a grain derived from wild grasses they had previously gathered. Over the next three thousand years the Saharan farmers domesticated pearl millet, blackeyed peas, a kind of peanut, sesame, and gourds. In the Ethiopian highlands, farmers domesticated finger millet and a grain called tef. The return of drier conditions about 5000 b.c.e. led many Saharan farmers to move to the Nile Valley, where the annual flooding of the river provided moisture for farming. People in the rain forests of equatorial West Africa domesticated yams and rice.
Rice, which thrives in warm and wet conditions, was first domesticated in southern China, the northern half of Southeast Asia, or northern India, possibly as early as 10,000 b.c.e. but more likely closer to 5000 b.c.e. In India several pulses (including hyacinth beans, green grams, and black grams) domesticated about 2000 b.c.e. were cultivated along with rice. The inhabitants of the American continents were domesticating other crops by about 5000 b.c.e.: maize (mayz) (corn) in Mexico, manioc in Brazil and Panama, and beans and squash in Mesoamerica. By 4000 b.c.e., the inhabitants of Peru were developing potatoes and quinoa (kee-NOH-uh), a protein-rich seed grain. Insofar as their climates and soils permitted, other farming communities throughout the Americas adopted these crops, along with tomatoes and peppers.

Domesticated Animals and Pastoralism

The domestication of animals also expanded rapidly during these same millennia. The first domesticated animal was probably the dog, tamed to help early hunters in Siberia track game.Later animals were domesticated to provide meat, milk, and energy. Refuse heaps outside some Middle East villages during the centuries after 7000 b.c.e. show that sheep and goat bones gradually replaced gazelle bones. As wild sheep and goats scavenged for food scraps around villages, the tamer animals accepted human control and protection in exchange for a ready supply of food. Selective breeding for desirable characteristics such as high milk production and long wooly coats eventually led to distinct breeds of sheep and goats.
Elsewhere, other animal species were domesticated during the centuries before 3000 b.c.e.: wild cattle in northern Africa or the Middle East; donkeys in northern Africa; water buffalo in China; and humped-back Zebu (ZEE-boo) cattle in India. Varieties of domesticated animals spread from one region to another. Once cattle became tame enough to be yoked to plows, they became essential to grain production. In addition, animal droppings provided valuable fertilizer. In the Americas comparatively few species of wild animals were suitable for domestication, and domesticated animals could not spread from elsewhere because the land bridge to Asia had been submerged by raised sea levels. Domesticated llamas provided transport and wool, while guinea pigs and turkeys furnished meat. Hunting remained the most important source of meat for Amerindians.
In the more arid parts of Africa and Central Asia, pastoralism, a way of life dependent on large herds of small and large stock, predominated. As the Sahara approached its maximum dryness around 2500 b.c.e., pastoralists replaced farmers, who migrated southward. Moving their herds to new pastures and watering places throughout the year made pastoralists almost as mobile as foragers and discouraged accumulation of bulky possessions and construction of substantial dwellings. Early herders probably relied more heavily on milk than on meat, since killing animals reduced their herds. During wet seasons, they may also have done some hasty crop cultivation or bartered meat and skins for plant foods with nearby farming communities.

Agriculture and Ecological Crisis

Why did the Agricultural Revolutions occur? Some theories assume that people were drawn to food production by its obvious advantages. It has recently been suggested that people in the Middle East might have settled down so they could grow enough grains to ensure themselves a ready supply of beer. However, most experts believe that climate change drove people to abandon hunting and gathering in favor of agriculture or pastoralism. With the end of the Great Ice Age, the temperate lands became exceptionally warm between 6000 and 2000 b.c.e., the era when people in many parts of the world adopted agriculture. The precise nature of the crisis probably varied. Shortages of wild food in the Middle East caused by a dry spell or population growth may have prodded people to take up food production. Elsewhere, a warmer, wetter climate could turn grasslands into forest, reducing supplies of game and wild grains.
In many drier parts of the world, where wild food remained abundant, people did not take up agriculture. The inhabitants of Australia continued to rely exclusively on foraging until recent centuries. Many Amerindians in the arid grasslands from Alaska to the Gulf of Mexico hunted bison, while in the Pacific Northwest others took up salmon-fishing. Abundant supplies of fish, shellfish, and aquatic animals permitted food gatherers east of the Mississippi River to thrive. In Africa conditions favored retention of the older ways in the equatorial rain forest and in the southern part of the continent. The reindeer-based societies of northern Eurasia were also unaffected by the spread of farming.
Whatever the causes, the gradual adoption of food production transformed most parts of the world. A hundred thousand years ago there were fewer than 2 million people, and their range was largely confined to the temperate and tropical regions of Africa and Eurasia. The population may have fallen even lower during the last glacial epoch, between 32,000 and 13,000 years ago. Then, as the glaciers retreated and people took up agriculture, their numbers rose. World population may have reached 10 million by 5000 b.c.e. and then mushroomed to between 50 million and 100 million by 1000 b.c.e. This increase led to important changes in social and cultural life.

By Richard W. Bulliet-(Columbia University), Pamela Kyle Crossley- (Dartmouth College), Daniel R. Headrick- (Roosevelt University), Steven W. Hirsch- (Tufts University), Lyman L. Johnson- (University of North Carolina—Charlotte) & David Northrup- (Boston College) in the book "The Earth and Its Peoples"- A Global History, Wadsworth (Cengage Learning), U.S.A.,2011, excerpts p.17-21. Adapted and illustrated to be posted by Leopoldo Costa.

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