The origin of agriculture cannot be documented with certainty because it began before recorded history. Scholars try to reconstruct a logical sequence of events based on fragments of information about ancient agricultural practices and historical environmental conditions. Improvements in cultivating plants and domesticating animals evolved over thousands of years. This section offers an explanation for the origin and diffusion of agriculture.
Before the invention of agriculture, all humans probably obtained the food they needed for survival through hunting for animals, fishing, or gathering plants (such as berries, nuts, fruits, and roots). Hunters and gatherers lived in small groups of usually fewer than 50 persons because a larger number would quickly exhaust the available resources within walking distance.
These groups traveled frequently, establishing new home bases or camps. The direction and frequency of migration depended on the movement of game and the seasonal growth of plants at various locations. We can assume that groups communicated with each other concerning matters such as hunting rights and intermarriage. For the most part, they kept the peace by steering clear of each other’s territory. The group collected food often, perhaps daily. The amount of time needed for each day’s food search varied, depending on local conditions. The men hunted game or fished, and the women collected berries, nuts, and roots. This gendered division of labor sounds like a stereotype but is based on evidence from archaeology and anthropology.
Today, perhaps a quarter-million people, or less than 0.005 percent of the world’s population, still survive by hunting and gathering rather than by agriculture. Contemporary hunting and gathering societies are isolated groups that live on the periphery of world settlement, but they provide insight into human customs that prevailed in prehistoric times, before the invention of agriculture (Figure 9-18).
Hunter Gatherers
San people, Botswana.
The process that began when human beings first domesticated plants and animals and no longer relied entirely on hunting and gathering became known as the agricultural revolution. Geographers and other scientists believe that the agricultural revolution occurred around the year 8000 B.C.E. because the world’s population began to grow at a more rapid rate than it had in the past. By growing plants and raising animals, human beings created larger and more stable sources of food, so more people could survive.
Scientists do not agree on whether the agricultural revolution originated primarily because of environmental factors or cultural factors. Probably a combination of both factors contributed:
Environmental factors. The first domestication of crops and animals coincided with climate change that marked the end of the last ice age. At that time, permanent ice cover receded from Earth’s mid-latitudes to the polar regions, resulting in a massive redistribution of humans, other animals, and plants.
Cultural factors. A preference for living in a fixed place rather than as nomads may have led hunters and gatherers to build permanent settlements and to store surplus vegetation there. In gathering wild vegetation, people inevitably cut plants and dropped berries, fruits, and seeds. These hunters probably observed that, over time, damaged or discarded food produced new plants. They may have deliberately cut plants or dropped berries on the ground to see if they would produce new plants. Subsequent generations learned to pour water over the site and to introduce manure and other soil improvements. Over thousands of years, plant cultivation apparently evolved from a combination of observation and experiment into a deliberate process.
Scientists agree that agriculture originated in multiple hearths around the world: Southwest Asia, East Asia, sub-Saharan Africa, and Latin America. Even within these hearths, scientists have determined that agriculture was invented independently by multiple groups.
Agriculture Hearths and Dispersal Routes
Southwest Asia. The earliest crops domesticated in Southwest Asia around 10,000 years ago are thought to have been barley, wheat, lentil, and olive. Southwest Asia is also thought to have been the hearth for the domestication of the largest number of animals that would prove to be most important for agriculture, including cattle, goats, pigs, and sheep, between 8,000 and 9,000 years ago. Domestication of the dog is thought to date even earlier, around 12,000 years ago. From this hearth, cultivation diffused west to Europe and east to Central Asia.
East Asia. Rice is now thought to have been domesticated in East Asia more than 10,000 years ago, along the Yangtze River in eastern China. Millet was cultivated at an early date along the Yellow River.
Central and South Asia. Chickens are thought to have diffused from South Asia around 4,000 years ago. The horse is considered to have been domesticated in Central Asia. Diffusion of the domesticated horse is thought to be associated with the diffusion of the Indo-European language, as discussed in Chapter 5.
Sub-Saharan Africa. Sorghum was domesticated in central Africa around 8,000 years ago. Yams may have been domesticated even earlier. Millet and rice may have been domesticated in sub-Saharan Africa independently of the hearth in East Asia. From central Africa, domestication of crops probably diffused further south in Africa.
Latin America. Two important hearths of crop domestication are thought to have emerged in Mexico and Peru around 4,000 to 5,000 years ago. Mexico is considered a hearth for beans and cotton, and Peru for potato. The most important contribution of the Americas to crop domestication, maize (corn), may have emerged in the two hearths independently around the same time. From these two hearths, cultivation of maize and other crops diffused northward into North America and southward into tropical South America. Some researchers place the origin of squash in the southeastern present-day United States.
That agriculture had multiple origins means that, from earliest times, people have produced food in distinctive ways in different regions. This diversity derives from a unique legacy of wild plants, climatic conditions, and cultural preferences in each region. Improved communications in recent centuries have encouraged the diffusion of some plants to varied locations around the world. Many plants and animals thrive across a wide portion of Earth’s surface, not just in their place of original domestication. The transfer of plants and animals, as well as people, culture, and technology, between the Western Hemisphere and Europe, as a result of European colonialization and trade, is known as the Columbian Exchange. After 1500, for example, wheat, oats, and barley diffused to the Western Hemisphere and maize to the Eastern Hemisphere.
Based on the below map Did crops diffuse primarily in an east-west pattern, or a south-to-north pattern? Why?