Clark Larsen Answers Students FAQs
1. Question: How, when, and where did the transition from hunting-gathering to farming occur?
Response: The initial transition from hunting-gathering to agriculture took place approximately 10,000 yBP in the Fertile Crescent region of the Jordan Valley in Southwest Asia (today, the Middle East). Prior to this, people began to manipulate the growth cycles of plants, working to promote better plant production. The shift to farming, however, was not immediate. The transition was very slow, lasting several thousand years. Early after the initial plant domestication, wild plants were still utilized. Eventually, there was a shift to greater reliance on domesticated plants, and less use of wild plants. Later, full-blown agriculture dominated, as wild plants were used more rarely. After agriculture began in Southwest Asia, it was followed by domestication of a variety of plants in Central Mexico, South China, North China, the South Central Andes, the Eastern United States, and Sub-Saharan Africa.
See Figure 13.3 Adoption of Agriculture
2. Question: What are the advantages and disadvantages of agriculture?
Response: A variety of advantages resulted from the shift to agriculture. First, there was more food for a larger number of people, so population size was able to increase. In addition, a surplus of food could be created. There was more food produced than could be consumed during the season, leading to storage of food, like grains, for a long period of time. This enabled the population to prepare for times of food shortages due to droughts, floods, or other environmental disruptions. By storing surplus food, the increased population size could be maintained over a long period of time. A number of disadvantages also resulted from farming. First, agriculture placed higher demands on the natural environment, leading to problems like soil exhaustion. In addition, since populations were more sedentary, they were also more likely to pollute their surrounding environment. Neighboring populations began to compete for resources, such as good farmland and adequate water supplies, leading to conflict. Overhunting resulted in the loss of wild species and an overall decline in biodiversity. Finally, a variety of negative health effects occurred in conjunction with agriculture.
3. Question: How and why did craniofacial changes take place with the transition to agriculture?
Response: Craniofacial changes occurred in conjunction with the shift to farming, because the types of foods consumed and their degree of softness changed. Foragers consumed tougher foods, requiring a larger chewing apparatus. Their crania were longer front to back, and they had larger faces and jaws along with large masticatory muscles. With the beginning of agriculture and the use of technology for cooking, food, such as grains, was softer, requiring less force to chew. As a result, masticatory muscles reduced in size, creating less mechanical demand on the bones of the face and jaws. Over time, the bones of the face and jaws reduced in size as well. The craniofacial shape of agriculturalists included a less-projecting face and a shorter, wider cranial vault. In addition, the smaller jaws had less room for the teeth. Various types of malocclusion of the teeth occurred as a result.
See Figure 13.12 Craniofacial Changes
4. Question: What were the health consequences of shifting to agriculture?
Response: The shift from hunting-gathering to farming created a number of negative health effects. First, rates of infection increased, reflected by the periosteal reactions on skeletal remains. Evidence of iron deficiency, evidenced by porotic hyperostosis and cribra orbitalia, also increased, as agriculturalists relied heavily on a single iron-deficient crop as their source of food. Linear enamel hypoplasias and microdefects of tooth enamel were more frequent in farmers, due to malnutrition, disease, or other sources of stress. In addition, the teeth displayed greater rates of dental caries following the transition to farming, as the diet focused on high carbohydrate consumption. Finally, with the transition to agriculture, the accumulative effects of nutrition, disease, and other sources of stress were reflected in the reduced skeletal growth and development in children and in the reduced adult height.
See Figure 13.22 Changes in Oral Health
5. Question: How did the skeleton adapt to changes in lifestyle and labor with the transition from hunting-gathering to farming?
Response: The shift to agriculture also caused a shift in type of labor and overall lifestyle. These changes are reflected in the skeleton, as the agriculturalists had smaller, less robust bones than the hunter-gatherers, resulting from an overall reduction in workload. This is also shown in the reduced osteoarthritis of farmers compared to hunter-gatherers. Since osteoarthritis results from repetitive use of a joint, a reduction in osteoarthritis of certain joints reflects their diminished use in labor and overall activity. Finally, utilizing cross-sectional geometric properties of bone, the skeletons of agriculturalists show reduced bone strength, reflecting less mechanical stress placed on the skeleton during life. A reduction in mechanical stress is the result of less use and/or loading of the bone during regular activities. This, too, then shows that the agriculturalists experienced reduced labor after transitioning from hunting-gathering.
See Figure 13.26 Biological Consequences, part 1
See Figure 13.26 Biological Consequences, part 2