Several hypotheses exist to explain the development of agriculture: Childe’s oasis theory; Sauer’s sedentary hypothesis; and Binford’s marginal habitat hypothesis.
V.G. Childe’s oasis theory proposed that major climate changes following the Pleistocene created “oases” of habitable regions, which forced humans into close proximity to plants and animals, causing them to develop familiarity with each other. This, Childe presumed, made it easier for humans to adapt plants or animals for their uses. One of the faults with this hypothesis is that it fails to explain why previous interglacial periods didn’t result in domestication or why domestication occurred without “oases” of habitation.
Carl Sauer’s sedentary hypothesis suggested that domestication began because of rich resources that freed people to experiment, giving rise to domestication. Luis Binford accepted this explanation, but argued that it wouldn’t be reason enough to abandon hunting-gathering in favor of the more difficult and labor-intensive food production strategy. Binford’s hypothesis of marginal habitat was, then, that demography became the driving force to make food production a favorable strategy.
Binford’s hypothesis, in my opinion, is represented in both the Tehuacan Valley of Mesoamerica as well as the Levant of the Near East.
The microbands of 1 to 2 families in the Tehuacan Valley at around 10,000 – 7,000 years ago were hunter-gatherers, but, as populations increased, they found themselves increasingly circumscribed to the environment, which naturally gave rise to competition for resources resulting in conflicts and unifications as they found social solutions to their resource problems. At around 7,000 – 5,000 years ago, domesticates like avocado, chilis and squash were introduced to the Tehuacan Valley. Maize is introduced at the end of this period, but isn’t an important part of the diet.
Between 5,000 and 3,500 years ago macrobands of up to 100 people emerged as did new domesticates of like the bottle gourd and crooked-neck squash. In addition, the mano and metate is introduced for grinding. Maize is used, but not as an important member of the diet. It was between 3,500 – 2,300 years ago that sites in the valley became the most sedentary and were occupied year round. It was also at this point that corn appeared as a clearly more important addition to the diet and with larger kernels that must have developed due to selective processes that affected the development of the species. Cotton is also being used and, perhaps, cultivated. River terraces are settled and permanent structures in the form of pit houses are used.
The Natufian culture of the Levant in the Near East also began as a hunter-gatherer society at around 13,000 – 12,800 years ago. Climatic improvements of this period were favorable to hunting and gathering food resources, but this also made it favorable for population increases. Foragers during this period were socially affected since nearly every eco-zone was occupied, pressuring them into semi-sedentary lifeways with reduced mobility. The wetter conditions made sedentism a favorable and practical lifeway. Early Natufians, often referred to as the earliest farmers, certainly cultivated wild wheat and barley, as evidenced by sickle blade analysis that revealed silica gloss on microliths from reaping grains. Their interactions with cereal grains and other plants likely led to cultivation as conditions became challenging with the Younger Dryas period of dryer, colder conditions that lasted from 12,900 – 11,500 years before present as higher elevations saw a brief but rapid return to glacial conditions. In the Levant, this caused rapid reduction in vegetation belts, forcing humans to seek new subsistence strategies.
Intentional cultivation was now the key to surviving as Late Natufians responded to the effects of the Younger Dryas, which likely caused unintentional modification to the plants as certain characters of the species were selected, specifically a tougher rachis that didn’t allow the grain to easily disarticulate from the central stalk at maturity. Wheat became an important staple for the region, proving to be adaptable and able to provide necessary nutrients while affording the ability to be stored for consumption in times of famine. Sedentary lifeways were now necessary because of either the demographic problems associated with population densities or because of the need to manage and store crops. By the time farming was in full-swing in the Levant, villages of 300-500 individuals were present.
In both the Tehuacan and the Natufian cultures, demographic pressures provided the impetus for moving to sedentism and farming as macrobands and early chiefdoms of hundreds of individuals sought viable subsistence strategies. Competition for resources may have led to warfare as well as unification, but the result was people working toward common goals of cultivating plants and managing animals in established “homelands.” With the Levantians, developing their staple crop of wheat was relatively rapid compared with the Mesoamericans who domesticated gourds, chilis, avocados and cotton before maize became an overwhelming important staple. In fact, maize was domesticated but remained a relatively unimportant crop for about 2,000 years before it was cultivated in significant quantities. Still, both cultures shared striking similarities in demographic pressures as their populations grew; the development of pit houses as they made the transition from mobile to sedentary; the use of grinding stones -mano and metate in Mesoamerica, and the quern in the Levant; the domestication of the dog; the development of pottery; the use of storage pits; and so on. One of the most significant differences was, perhaps, the introduction of the plow. This technology didn’t find its way into Mesoamerica because of a lack of draft animals until equines were introduced by European invaders.
Binford, Lewis R. (1968). “Post-Pleistocene Adaptations.” In New Perspectives in Archaeology. Sally R. Binford and Lewis R. Binford, eds. Aldine Publishing Company, Chicago, pp. 313-342.
Braidwood, Robert J. (1960). The Agricultural Revolution. Scientific American, vol. 203, pp. 130-48.
Harris, Gregory (2007). Red hot chili pepper research spices up historical record: Archaeologists trace domestication and dispersal of Capsicum species. Eureka Alert [15-Feb-2007].
Sauer, Carl, O (1952) Agricultural origins and dispersals. MIT Press, Cambridge, MA