14-Introduction

At different times in different parts of the world, Paleolithic and Mesolithic hunter-gatherer groups around the world shifted to an agricultural lifestyle in what is called the Neolithic (New Stone Age) Revolution. As populations grew and climates changed, wild animal populations and vegetation density fluctuated. People began to raise crops and domesticate animals in order to supplement their diet. Societies gradually transitioned from following herds of animals and finding wild vegetation to living in homes and taking care of domesticated plants and animals.

Figure 14‑1. Green areas show locations of the origins of wheat in Middle East(11,000 BP= 11,000 years ago), rice in China (9,000 BP), corn in Mexico (8,000 BP), potatoes in Peru (8,000 BP), yams in Africa (5,000–4,000 BP), and sunflowers and squash in America (4,000–3,000 BP).The blue lines show the spread of these crops. For example, potatoes spread throughout South America, and corn growing regions spread into America and Central America. Credit: Joey Roe. Used here per CC BY-SA 3.0.

Agriculture arose independently in the Middle East (wheat and barley), China (rice), Mexico (corn), South America (potatoes and tomatoes), Africa (yams), and North America (squash and sunflower). Domestication of crops began in locations with suitable species and then spread to adjacent regions (blue lines in Figure 14‑1). Archaeologists define the agricultural revolution in each region as the beginning of the Neolithic (New Stone Age) for that region.

At the heart of the Neolithic Revolution was the domestication of plants and animals. “Domestication is a sustained multi-generational relationship in which one group of organisms assumes a significant degree of influence over the reproduction and care of another group to secure a more predictable supply of resources from that second group.” [1]

Modern people generally do not understand nor appreciate the effort that went into domestication, which generally took thousands of years. Over dozens of human generations, people selected for favorable traits as they planted or bred selected plants or animals.

Agricultural productivity is dramatically higher than natural ecosystem productivity. Prior to the advent of agriculture, all of the natural ecosystems of the world supported a total of ten million people, an average of a few hunter-gatherers per square mile. Modern intensive agriculture supports thousands of people per square mile (Table 14-1) and 7.5 billion people in the world.

Table 14-1. Agricultural systems and number of people supported per square mile. Modified from Smil [2]

Type Beginning Minimum Maximum

Foraging (hunter-gatherers) 2,500,000 0 2

Early cropping methods 23,000 BP… 30 150

Intensive irrigated agriculture 7500 BP… 300 2,600

Modern farming 2,600 5,200

Greenhouses 25,000 50,000

There are advantages and disadvantages with agriculture. Traditional agriculture was not a paradise but was hard and backbreaking work. Hunter gatherers had healthier bones and teeth and generally had more relaxed lifestyles than those in early agricultural groups. Cultivation, seeding, weeding, and harvesting all required extensive time and human energy. The invention of animal powered cultivation systems such as the ox and plow transferred much of the work to animals, but agriculture was still laborious. As a result, civilizations in Mesopotamia and Egypt developed class systems and slavery in order to produce food. Recently, agricultural mechanization decreased the need for human labor in agriculture. Another disadvantage of agriculture was a decrease in food diversity since agricultural groups tend to consume large amounts of one type of starchy food, such as wheat or rice.

Agriculture is harmful to natural ecosystems and environmental diversity. In many regions, agriculture completely replaced natural ecosystems with monocultures. This is not necessarily the case with smaller scale agriculture. Excessive use of pesticides, fertilizer, and water can also have detrimental effects on the environment. In the modern world, the question of whether the environment is more important than agriculture is not necessarily an either or question. Planners and environmentalists can look at individual geographic areas on a case by case basis and determine an optimal extent of agriculture and whether agriculture will have an overall positive or negative effect on a region. One area of current interest is incorporating agriculture back into cities.

Figure 14‑2. Fertile Crescent. Credit: NASA.

Animal domestication began with dogs and continued with farm animals. Animals that were domesticated generally had traits suitable for domestication, which include growth rate, breeding habits, temperament, and herding behavior. Traits were selected over thousands of years, which eventually led to the domesticated animals of the modern world. Almost all domesticated farm animals were first domesticated in the Middle East. One reason for this is that the animals suitable for domestication lived in this region. As with agriculture, there are environmental problems associated with farm animal domestication. For example, farm animals generate a huge amount of waste, far more than humans. The enormous number of domesticated cows in the world emit so much methane that they cause global warming.

Agriculture began in the Fertile Crescent (Figure 14‑2), in the Jordan Valley (Levant), northern Iraq and Syria, and Iranian highlands.

There were three phases of the Neolithic in the Middle East, the prepottery Neolithic A (PPNA) and Prepottery Neolithic B (PPNB) along the northern perimeter of the Fertile Crescent, and the Late Neolithic in southern Mesopotamian Plain.

Northern and Western Fertile Crescent (PPN = Pre-pottery Neolithic)

o Natufian (Levant): 12,000 to 10,200 BC

o PPNA: (Levant, Northern Iraq and Western Iran) 10,200 to 8800 BC

o PPNB: (Expansion to Turkey) 8800 to 6400 BC

Southern Mesopotamia (LN = Late Neolithic)

o Ubaid/Uruk culture: 5800 to 3500 BC

References

[1] Wikipedia.

[2] Vaclav Smil, World History and Energy. In Concise Encyclopedia of the History of Energy. Ed Cutler Cleveland (San Diego, Ca: Elsevier Press, 2009), 331-342.

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Pastoral nomad sheepherder's tent. Credit: Hamed Samer. Used here per CC BY 2.0.

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