To the Archaeological Record

According to the archaeological record, agriculture emerged as the predominant form of food production directly from a hunter-gatherer background, without any major significance attributable to external diffusion,20 in at least five major regions of the world (Figure 1.3):

1.the Fertile Crescent of Southwest Asia (wheat, barley, pea, lentil, sheep, goat, pig, cattle);

2.the middle and lower courses of the Yangzi and Yellow river basins of China (rice, foxtail millet, many tubers and fruits, pig, poultry);

3.New Guinea, probably in the interior highlands (taro, sugar cane, pandanus, banana, no domestic animals);

4.the tropical regions of the Americas, perhaps with one or more foci in central Mexico and northern South America (maize, beans, squashes, manioc, many fruits and tubers, minor domestic animals);

5.the Eastern Woodlands of the USA (squashes and various seed-bearing plants, no domestic animals).

It is possible that central (Sub-Saharan) Africa also witnessed early agricultural developments, particularly in the Sahel zone for millets and north of the rain forest in West Africa for yams and African rice. There are also claims of a similar nature for southern India.

In understanding the origins of agriculture in these regions we need to consider for each of them, wherever data exist, a number of botanical/zoological, environmental, and archaeological questions:

a)Where did the progenitors of the major domesticated plants and animals live when domestication first occurred (bearing in mind that modem

environments and species distributions can be very different from those of several millennia ago)?

b)How did climatic conditions and environments change during the time spans in which agriculture emerged in the various regions? What were the results of these changes on faunas, floras, and human economies?

c)What kinds of hunting and gathering cultures made the transition to agriculture in the various regions? How important were preexisting patterns of sedentism, food storage, and opportunities for asymmetrical accumulations of wealth as opposed to egalitarian sharing?

d)How rapidly did particular transitions occur, and over what extents of territory initially?

e)What patterning in archaeological/ cultural terms is associated with the transition?

These questions will be addressed in more detail as we proceed through the evidence from each region. Coverage for different areas is very uneven and our understanding, in terms of sheer quantity of archaeological data, is dominated very much by the transition in the Levant. But we have enough information to know that the Levant model is unlikely to be valid for any other regions, apart perhaps from China, and even here only with modification. The routes to agricultural dependence were multiple.

Chapter 3

The Beginnings of Agriculture in

Southwest Asia

Southwest Asia is by far the best-known region in world prehistory for the transition to agriculture, especially its western portion, generally known as the Levant. The Southwest Asian trajectory does not necessarily provide the model for all the other areas of transition, but it had, in terms of world significance, the greatest impact on subsequent human affairs, followed closely by that in China.

The setting for the transition to agriculture in Southwest Asia was a zone of open woodlands and grasslands, with stands of wild cereals and legumes, that forms part of what has become famous in archaeology as the "Fertile Crescent" (Figure 3.1). This runs from the Jordan Valley northwards through inland Syria, into southeastern Turkey (Anatolia), then eastwards through northern Iraq, and finally southeastward along the Zagros foothills of western Iran. Today, the Fertile Crescent receives annually more than 200 millimeters of relatively reliable winter-focused rainfall, being flanked to its south by desert and to its north and east by high mountains. It is essentially a zone of gentle gradients with ample areas of alluvial soil, where climatic conditions allowed rain-fed agriculture to develop without elaborate irrigation requirements.

Some very significant points may first be noted about the transition to agriculture and plant/animal domestication in the Fertile Crescent:

1.It was closely related in timing with the first stable and continuing amelioration of post-glacial climate, focused on the period between 9500 and 7500 BC (calibrated radiocarbon dates).

2.It occurred in a region of winter rainfall with very marked rainfall seasonality.

3.It involved a combination of cereal, legume, and animal domestication, a combination of unrivalled productive significance in world prehistory (Diamond 2002).

4.It was aceramic and Neolithic in technological orientation (i.e., no pottery in the early stages, and no smelted as opposed to hammered metal).

5.It evolved from a baseline of complex hunting and gathering, with presumed sedentary or near-sedentary settlements.

6.It was revolutionary, both in tempo and in impact on the western/central Eurasian and northern African cultural canvases.'

The Quaternary pollen record from Southwest Asia, in combination with other paleoclimatic indicators, outlines the transformations of climate and vegetation that have occurred since 20,000 years ago.' In the Fertile Crescent, the last glacial maximum was a period of cold dry conditions, with widespread relatively treeless steppes. Average temperatures were 4° or more below present and wild cereals apparently existed only in protected refuge areas. Between 15,000 and 12,000 BC there were rises in temperature, rainfall, and atmospheric carbon dioxide almost to present-day levels, but they were episodic (see Figure 2.3). About 11,000 Bc, an unusually rapid and severe swing took the region back into cold and dry glacial conditions, a situation that lasted until about 9500 BC. This cold phase is termed the Younger Dryas.

The Younger Dryas was followed after 9500 Bc by a very rapid re-warming, by as much as 7°C in average annual temperature, to Early Holocene conditions; warm and wet, with increased winter rainfall, and increased summer monsoon rainfall in some southerly regions. These conditions were excellent for a widespread radiation of wild cereals and legumes. Just as important, they were associated with the establishment of a high level of climatic stability. Between about 9000 and 7300 Bc, domesticated cereals, legumes, and herd animals rapidly acquired dominant roles in human subsistence throughout Southwest Asia. If this association with the onset of a relatively stable and encouraging Holocene climate was pure coincidence, then it was one of the most remarkable coincidences ever to occur in human prehistory.

The Domestication of Plants in the Fertile

Crescent

Using available palynological data (van Zeist and Bottema 1991; Hillman 1996; Moore et al. 2000), it is possible to offer a fairly specific reconstruction of where the wild cereal species ultimately to be domesticated were distributed on the eve of domestication and agriculture. If Gordon Hillman's reconstruction (Figure 3.1) is correct, they would have grown mainly in the western and northern parts of the Fertile Crescent, rather than in the colder and more continental east. The botanical and archaeological evidence is in accord with this reconstruction and suggests that plant cultivation also began in this area.'

As stressed by Jared Diamond (1997), Southwest Asia has the largest area of Mediterranean climate (hot dry summers, cool wet winters) in the world, plus the greatest range of altitudinal variation within this climatic category. It also has the largest number of large-seeded annual wild cereal and pod-bearing legume species (legumes include broad beans, peas, chick peas, and lentils) of any region of Mediterranean climate, all genetically programmed to germinate and grow through the short daylengths of the wet winter and to remain dormant in seed form in the ground during the hot dry summer. Annual cereals tend to have larger grains than perennial ones because of the function of the grains as food stores during dormancy. Fortunately for humans, those cereals and legumes chosen for ultimate domestication also happened to be selfrather than cross-pollinating. In other words, useful characters developed as a result of human management would not be easily swamped out of successive generations by back-crossing with wild plants, especially if such modified varieties were planted beyond the normal ranges of the wild forms. Stable lines of domesticates could be developed from the beginning. These botanical advantages possessed by Southwest Asian cereals were of fundamental importance.

Moving now to the cereals themselves, the wheat species termed emmer (a hulled tetraploid') and einkorn (a hulled diploid) were the first to be widely cultivated in the Fertile Crescent, together with barley and rye. Actual

domesticated (morphological) features in these cereals are present in a few sites by about 8500 BC, although domesticated rye is currently claimed much earlier than this at Abu Hureyra in Syria. By 8000 BC, naked-grained (free-threshing) tetraploid and hexaploid wheats had also made an appearance. Bread wheat, a naked-grained hexaploid, was brought into domestication following an introgression between emmer and a wild species of goat grass. Barley was cultivated initially in its natural 2-row form, with the higher-yielding 6-row barley developing rapidly through cultivator selection in well-watered environments. Wild 2-row barley has a widespread distribution across Southwest Asia extending to western Anatolia, North Africa, and Afghanistan, but occurrences in archaeological contexts' suggest initial cultivation in the Fertile Crescent. Emmer is of Levant origin, and einkorn is currently believed to have originated in southeastern Anatolia.

The legumes pea, lentil, and chickpea were all of Levant origin, possibly from an area encompassing northern Syria and southeastern Anatolia, but none of these occur in domesticated form until after 8000 BC, later than emmer and barley on present evidence (Ladizinsky 1999; Lev-Yadun et al. 2000; Garrard 1999). Another important domesticate of the Fertile Crescent was flax, the fiber source for linen, attested in Neolithic textile remains from dry caves in Israel.

From the viewpoint of those populations making the transition to agriculture, wild cereals and legumes have characteristics that we might consider not very userfriendly. Their ears and pods disintegrate or burst open when they are ripe so that the grains can disperse - for cereals this is referred to as shattering, or dehiscence in the case of the legumes. The grains are also encased in tough protective glumes (Figure 3.2B) so they can survive predation during dispersal and dormancy. Individual grains, ears or pods on a single plant will not ripen synchronously, causing difficulties for efficient harvesting. The wild Southwest Asian cereals and legumes will only germinate and mature during a relatively fixed period each year (autumn to spring), owing to their sensitivity to temperature, moisture, and day-length variations and their requirements for vernalization. Early wild cereal and legume exploiters would probably have wanted to harvest the ears or pods slightly unripe, before the seed dispersal phase triggered by full ripeness. They would then have needed to dry the grains in the sun or roast them, before grinding.'

Figure 3.2 Ear, spikelet, and grain of wild (A, B, C) and domesticated (D, E, F) einkorn wheat, Triticum monococcum. From Zohary and Hopf 2000.

The overall impact of the domesticatory process by humans has been to alter, especially for the Southwest Asian cereals (but also for all other major world cereal crops), all the wild states listed above toward a non-shattering habit when

ripe, grains held loosely within weak glumes (naked grains), synchronous ripening in individual plants and across stands, lessened dormancy of the grains (meaning they can be planted year-round as long as water is available), larger grains, and larger and more compact ears (Figure 3.2D). Obviously, cereals with such features will not be well equipped to survive by themselves in the wild - but then they will not need to with human cultivators at their service. From a perspective of population numbers, domesticated plants and animals can be stated to benefit just as much as humans from a mutualistic domesticatory relationship.

A major question that arises with all these crops is that of how many independent domestications occurred for each of them. This is an important issue, since if most crops were only domesticated once, as believed by Daniel Zohary (1996, 1999) and Mark Blumler (1998), then it could imply that huntergatherers all over late Pleistocene Southwest Asia did not simply start, independently, cultivating the wild cereals that just happened to be growing near their camps. It implies that, once domesticated, the major cereals and legumes spread "pre-emptively" throughout the burgeoning agricultural world, rendering it non-economic for anyone to attempt to domesticate separate local wild varieties. At present the genetics behind this issue are a little clouded; whereas einkorn is claimed to have been domesticated in just one locality in the Karacadag Mountains of southeastern Anatolia (Heun et al. 1997), the evidence for the other crops is not so clear and more than one domestication event is likely, especially for barley (Jones and Brown 2000; Willcox 2002).

Despite the uncertainty, it has recently been claimed that all the main founder crops of the Near East were domesticated within a single small area of northern Syria and southeastern Anatolia, an idea driven partly by the limited distribution of the chick pea in wild form. This suggests almost a single point of origin for the Near Eastern Neolithic, a possibility that cannot easily be negated and one that would be of great importance were it to be independently verified (Lev-Yadun et al. 2000; Gopher et al. 2001).