Kamis, 01 Desember 2011

A brief history of food production & Foraging societies

A brief history of food production
Every new find of hominid remains in East Africa reignites the controversy about the origin of our species, but at least one conclusion remains unchanged: we have come from a long lineage of opportunistic foragers, and for millions of years both the natural diet and the foraging strategies of hominids resembled those of their primate ancestor (Whiten and Widdowson, 1992). Larger brains improved the odds of their survival but to secure food, hominids relied only on their muscles and on simple stratagems as scavengers, gatherers, hunters, and fishers helped by stone implements, bows and arrows and by fibrous or leather lines and nets. Controlled use of fire needed to prepare cooked food may have come first nearly half a million years ago, but a more certain time is about 250000 years ago (Goudsblom, 1992).
Childe’s (1951) idea of Neolithic Revolution has been one of the most unfortunate caricatures of human evolution: there was no sudden shift from foraging to sedentary farming. Diminishing returns in gathering and hunting led to a gradual extension of incipient cultivation present in many foraging societies, and foraging and agriculture commonly coexisted for very long periods of time (Smil, 1994). Similarly, there were no abrupt changes in the way most traditional agricultures produced food; some places experienced prolonged stagnation, or even declines, in overall food output, others have undergone gradual intensification of crop cultivation that has resulted in higher yields and more secure food supplies. Even then, traditional farming was able to produce only monotonous diets and it remained highly vulnerable to environmental stresses. Only modern agriculture, highly intensive and fossil fuel-based, has been able to produce enormous surpluses of food in all af uent nations and to raise most of the world’s populous developing countries at least close to, and for most of the Chinese even well above, subsistence minima.
Foraging societies
The great diversity of the preserved archaeological record makes it impossible to offer any simple generalizations concerning prehistoric diets. Modern studies of foraging societies that have survived in extreme environments (tropical rain forest, semideserts) into the 20th century have provided very limited insight into the lives of prehistoric foragers in more equable climates and more fertile areas. Moreover, these societies have often been affected by contacts with pastoralism, farmers or overseas migrants. Given the unimpressive physical endowment of early humans and the absence of effective weapons, it is most likely that our ancestors were initially much better scavengers than hunters (Blumenschine and Cavallo, 1992). Large predators often left behind partially eaten carcasses and this meat, or at least the nutritious bone marrow, could be reached by enterprising early humans before it was devoured by vultures and hyenas.
 Fishing, collecting of shellfish, and near-shore hunting of sea mammals provided diet unusually rich in proteins and made it possible to live in semi permanent, and even permanent, settlements (Price, 1991). In contrast, both gathering and hunting were surprisingly unrewarding in species-rich tropical forests where energy-rich seeds are a very small portion of total plant mass and are mostly inaccessible in high canopies, as are most animals, which are also relatively small and highly mobile. Grasslands and open woodlands offered much better opportunities for both collecting and hunting. Many highly nutritious seeds and nuts were easy to reach, and patches of large starchy roots and tubers provided particularly high energy returns. So did the hunting of many grasslands herbivores which were often killed without any weapons, by driving the  herds over precipices. This hunting was intensive enough to explain the disappearance of most large herbivores from preagricultural landscapes (Alroy, 2001).
There is no doubt that all pre agricultural societies were omnivorous and that although they collected and killed a large variety of plant and animal species only a few principal foodstuffs usually dominated their diets. Preference for seeds and nuts among gatherers was inevitable; they are easy to collect, and they combine high energy con-tent (13–26 MJ/kg) with relatively high protein shares (commonly above 10%). Wild grass seeds have as much food energy as cultivated grains (15MJ/kg), and nuts have energy densities up to 75% higher. All wild meat is an excellent source of protein ( 20%) but the esh of small and agile animals (e.g., hares or monkeys) contains very little fat ( 10%) and hence has very low energy density (5–6 MJ/kg). Consequently, there has been a widespread hunting preference for such large and relatively fatty species, such as mammoths and bison's (containing 10–12MJ/kg). Even so, except for maritime hunters of fatty fish (salmon) and mammals (whales, seals), lipids usually supplied no more than 20% of food energy in preagricultural societies.
The extremes of daily intakes of animal protein among the remaining foraging populations studied after 1950 range from more than 300 g/capita among Inuit feeding on whales, seals, fish, and caribou to less than 20 g a day for foragers in arid African environments subsisting mainly on nuts and tubers (Smil, 1994). Eaton and Konner (1997) used nutrient analyses of wild plant and animal foods eaten by recent gatherers and hunters in order to estimate the dominant composition of prevailing preagri-cultural diets. They concluded that compared to the typical recent US intakes they were more than twice as rich in fiber, potassium, and calcium, but contained less than one-third of today’s sodium consumption.
Prehistoric survival modes and diets were extremely diverse but this fact has not prevented some anthropologists making inadmissible generalizations. Undoubtedly, for some groups the total foraging effort was low, only a few hours a day, and this fact, confirmed by some modern field surveys, led to the portrayal of foragers as “the original af uent society” (Sahlins, 1972). This conclusion, based on very limited and highly debatable evidence, ignored the reality of much of the hard, and often dangerous, work in foraging and the frequency with which environmental stresses repeatedly affected most foraging societies. Seasonal food shortages in  actuating climates necessitated the eating of unpalatable plant tissues and led to weight loss, low fertility, high infant mortality, infanticide and often to devastating famines (Smil, 1994).


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