ORIGINS OF AGRICULTURE

Beginning of the Holocene period 10000 bp. Warmer, glacial melting with rise in sea level, wetter with more rain. More vegetation, fewer deserts. But not the same everywhere. Maybe just another interglacial, but now we have human intervention. Greenhouse effect? Culture supervenes on geology as well as physical evolution.

Mesolithic (European), Archaic (Americas) increased exploitation of the environment and continued subsistence shift.

Neolithic- beginning of agriculture 10000bp. Implicit is domestication of plants and animals. Change, via ARTIFICIAL selection, from wild forms to a more useful form, such as wolf to dog, grasses to wheat, etc. In domestication of animals, such as dogs and cattle, more successful if there is a strong dominance hierarchy in the herd. Then humans can become the most dominant and the other animals fall in line. As in artificial selective evolution of wolf to dog. The animals to be domesticated are selectively bred in captivity and thus modified from their wild ancestors. Dog wolf, cattle, auroch, pig wild boar, etc.

First, movements of animals were controlled, then selective breeding and regulation os sex ration and age structure. This changed the gene frequency and anatomical changes resulted. Apparently there were societal shifts back and forth between hunting and pastoralism befor actual herd management occurred. By about 10000 bp goats were being domesticated in the Zagros Mountains.

Why did agriculture originate? 2 groups of theories, environmental and demographic.

Environmental determinism- explanation of cultural behavior that see human action in response to environmental circumstances. Modern differences between societies may be explained because of differences between environments, not because of biological differences between people themselves. People became sedentary because that’s where the food was. "Oasis" theory of V Gordon Childe.

End of Pleistocene 10000BP. Glaciers retreat, warmer, and wetter; food sources changed and people followed the food. With more desertification in a colder, drier periods about 1000 years later, smaller areas, "oases", could support populations as the range of seed crops and animals was reduced. These resources were then so changed by human alteration that they became domesticated and could not survive as untended crops and livestock.

But recent work shows that there may not have been as much of a climate shift as previously thought.

Demographic, or cultural and historical reasons for domestication and agriculture.

1. Population pressure theories. Boserup 1965. Population at end of Pleistocene increased rapidly and people reached the carrying capacity (CC) of the environment, Carrying capacity is the number of people or organisms that a given environment can support. Agriculture was therefore developed. Hunter gatherers (HG) became more sedentary before agri, then with agri they had enough resources so they didn’t have to keep moving.

2. Marginal habitat hypothesis. Binford- Marginal zones. Agriculture in areas in which the CC was reached due to pop pressure. Then pop split and some went where CC not yet reached. Thus, when CC reached it was in the area that previously had the MOST, not the least, resources (opposite to Childe). The new migrants were forced to be nomads or pastoralists. CC being reached caused migration and people took plants and animals with them. In the new areas the stock could only survive with domestication.

In either case pop pressure and environmental pressure are related. In the Near East humans occupied every ecological niche by 10000bp, and population was in equilibrium, so people then had to move to marginal zones if the population was to expand.

3. Readiness hypothesis. Domestication for cultural reasons. There were no specific environmental reasons for it. Braidwoods excavated in the Zagros Mts in Iran and Iraq. Jarmo. They thought that first agri was in areas where plants and animals abundant, also against Childe.. No major stress environmentally, but good environmental conditions led to agriculture as experience of people with the semidomesticates increased. "Hilly flanks" Theory. Culture and history emphasized, domestication occurred because people could do it. There was new knowledge and specialization in subsistence. People became sedentary in places where wild plants and animals amenable to domestication were found. As more knowledge of the animals and plants was obtained, people used this knowledge.

Talk of "Agricultural Revolution," but really a slow process that didn’t happen all at once. Agriculture did not lead to settled towns, because there were settlements before full scale agriculture, and food production and HG were alternate strategies in the same groups. Some sort of cultural revolution before the agricultural one. Still much HG after cereal seeds were used in the Levant at 17000 bp and earliest cultivation at 13000 bp.

"Noah's flood" postulated that at 7500 bp, Med flows into Black Sea, banks overflow. People leave and disseminate agricultural techniques to Europe and Fertile Crescent. Possibly left in myth and cultural history as the Biblical flood.

Another debate is whether people actually moved from the Levant to Europe, or if the technology was spread without human migration. Recent work shows that there is a clinal distribution of a gene on the Y chromosome with only 2% in the Near East but 89% in the Basques and 98% in the West of Ireland, the last outposts of preNeolithic Europe. This implies that there was actually population movement.

Catal Huyuk, Turkey, 9000 bp. A town of 10000 people.. Not quite a city, no division of labor, occupied by farmers, decentralized. Individual residential structures with ovens, benches, storage areas. But had painted murals showing vultures attacking headless men, volcanoes, hunting. A rich symbolic life. Burials under the floors, like Jericho.

The consequence of the rise of agriculture was that more calories meant, ultimately, more people. Selecting the domesticates meant more complex society and a military advantage. So, agriculture not needed to feed more people because the rise of agriculture occurred before there were that many people.

To synthesize the above theories, probably what happened was that there was an ultimate shift to agriculture in these mixed economies.

Decrease wild food at the same time there was an increase in the domesticable wild plants. Extinction? Climate change worked in favor of artificial selection.

Development of technology to make production easier. Natufian suckles, baskets and underground pits for storage, mortars and pestles after 11000 BP.

As there were more agriculturalists, pure HGs became more geographically marginalized.

"Hearths of Domestication"

Problems with agriculture:

1. Plants selected for nutritional return, so big seed and less genetic variation. More prone to failure from disease and climate change such as drought.

2. More work for agriculturalists than HGs. Must prepare land, gather and harvest.

3. Plants in diet reduces variety of nutrients, so more disease. Also more infectious disease as people move permanently closer together in sedentary villages.

  1. Environmental degradation such as deforestation at Pueblo Bonito, for building material and fuel.
  2. Changes in culture caused by agriculture. People crowded closer together in villages, infectious disease such as tuberculosis

Evidence? Paleopathology, including porotic hyperostosis, enamel hypoplasia, growth resumption lines.

Now we have CULTURE as prime factor in the relation between people and the environment. Artificial rather than natural selection. Need rules of behavior in living together and in organizing defense, irrigation etc. This will lead to the rise of complex civilization.

Agriculture important because food production is critical in creating surpluses that can feed non food producing specialists and create a larger, denser population base. The means of transport of this food implies that domesticated animals were needed. All this is a prerequisite for the socially stratified, economically complex true civilizations to follow. Along with agriculture, technology necessary for innovation, and writing necessary for record keeping developed. Giving these agricultural societies a head start in the development of complex civilization.

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Mis à jour le 03/04/2019 pratclif.com