Ideas: A History from Fire to Freud

One reason for the distribution about the globe of these areas has been provided by Andrew Sherratt, from the Ashmolean Museum in Oxford. His theory is that three of these areas – the Middle East, Mesoamerica and the south-east Asian island chain – are what he calls ‘hot spots’: geologically and geographically they have been regions of constant change, where incredible pressures generated by tectonic plates moving over the surface of the earth created in these three places narrow isthmuses, producing a conjunction of special characteristics that are not seen elsewhere on earth. These special characteristics were, first, a sharp juxtaposition of hills, desert and alluvium (deposits of sand or mud formed by flowing water) and, second, narrow strips of land which caused a build-up of population so that the isthmus could not support traditional hunter-gathering.⁴ These ‘hot spots’ therefore became ‘nuclear areas’ where the prevailing conditions made it more urgent for early man in those regions to develop a different mode of subsistence.

Whatever the truth of this attractively simple theory, or in regard to the number of times agriculture was ‘invented’, there is little doubt that the very first time, chronologically speaking, that plants and animals were domesticated, was in the ‘fertile crescent’ of south-west Asia. To understand fully what we are talking about we need to grasp the nature of the evidence about domestication, which means in the first instance understanding the relatively new science of palynology, or pollen analysis. Plants – especially the wind-pollinated tree species – each produce thousands of pollen grains every year, the outer skins of which are very tough, and very resistant to decay. Pollen varies in shape and size and, being organic, can be carbon-dated. Its age and genus, if not its species, can therefore often be determined and this has enabled archaeo-botanists (a relatively new specialism) to reconstruct the surface vegetation of the earth at different periods in the past.

Plant remains (i.e., not just pollen) have now been identified and radio-carbon dated from hundreds of sites in the Middle East and, according to the Israeli geneticist Daniel Zohary, the picture is more or less clear. First, there were three cereals which formed the principal ‘founder crops’ of Neolithic agriculture. In order of importance, these were: emmer wheat (Triticum turgidum, subspecies dicoccum), barley (Hordeum vulgare) and einkorn wheat (Triticum monococcum). They first appeared in the tenth and ninth millennia BP. Second, the domestication of these cereals was accompanied by the cultivation of several ‘companion plants’, in particular the pea (Pisum sativum), the lentil (Lens culaniris), the chickpea (Cicer arietinum), bitter vetch (Vicia ervilia) and flax (Linum usitatissimum).⁵ In each case, the original wild variety, from which the domestic crop evolved, has now been identified; this enables us to see what advantages the domestic variants had over their wild cousins. In the case of einkorn wheat, for example, the main distinguishing trait between wild and cultivated varieties lies in the biology of seed dispersal. Wild einkorn has brittle ears, and the individual spikelets break up at maturity to disperse the seed. In the cultivated wheat, on the other hand, the mature ear is less brittle, stays intact, and will break only when threshed. In other words, to survive it needs to be reaped, and then sown. The same is true for the other crops: the domesticated varieties were less brittle than the wild types, so that the seeds are spread only once the plant has been reaped, thereby putting it under man’s control. Comparison of the DNA of the various wheats all over the fertile crescent shows that they are fundamentally identical, much less varied than the DNA of wild wheats. This suggests that in each case domestication occurred only once. ‘The plants with which food production started in the South West Asia “nuclear area” were transported (already as domesticated crops) to initiate agriculture all over these vast territories.’⁶