There’s really nothing better than a map to explain the history of domestication in an economic and effective fashion, but I have to say that this recent example from a paper on crop domestication in the Fertile Crescent misses the mark.
It’s supposed to show that…
…plant remains from archaeological sites dated to around 11,600-10,700 years ago suggest that in regions such as Turkey, Iran and Iraq, legumes, fruits and nuts dominated the diet, whereas cereals were the preferred types of plants in Jordan, Syria, Palestine and Israel.
Which I suppose it does, but I have to think they could have done better. Compare with this, from another recent paper, showing the prevalence of spotted coats in early domestic horses.
It’s still a bit busy, but much clearer than the previous one, I think.
Would be great to see an index of all such maps, maybe a mash-up in due course, even a GIF eventually?
“We propose that the cultivation of wild and domesticated cereals developed at different times across southwest Asia”. From the abstract – the rest is behind a paywall. I wonder how they knew that the wild cereals were being cultivated: they were certainly being gathered – going back 23,000 years.
There’s also something about “Domesticated-type cereal chaff” – Never heard that one before.
Perhaps this is about the prevalence of non-shattering vs. shattering cereal heads, the former supposedly selected for unconsciously by routine gathering, leading to domestication?
Perhaps the presentation could have been better, but this should not detract from the data. They are important, especially with regard to length of time of domestication as a process. Tanno K-i, Willcox G (2006) [How fast was wild wheat domesticated? 10.1126/science.1124635. Science 311:1886-1886] argued that domestication had taken several millennia by assembling data from _different_ archaeological sites in SW Asia. They showed that the younger the site, the higher the frequency of domesticated cereal remains (based on the proportion of non-shattering/shattering remains). They deduced from these data a domestication process duration of several millennia. There is, however, a confounding effect in this calculation, namely the fact that not all sites may have initiated cultivation and domestication at the same time. The differences in age of domestication may have been due to differences in the spread of agriculture in addition to or instead of different stages of domestication. All in all, this paper is a welcome addition to this issue.
The Shattering problem. I have just read a paper by Dorian Fuller saying:“If wild cereals were harvested simply by passing through stands and shaking or beating ears to knock seeds into a basket then the shattering, wild-type ears would be the ones to predominate in the next year’s crop. ” This is only true if you take the seeds in the basket and plant them next year (or harvest them at such a low intensity that much seed remains on the plant to fall later). If, as must have happened, you harvest at high intensity or repeatedly you leave whatever non-shattering seed there is in the population and the next years crop grows from this and eventually you get the supposedly `domestic’ character of a non-shattering population (often used as a marker for domestication) with no cultivation whatever. This could even happen with pest pressure: what about all those Quelea on sorghum? They only need to leave a few non-shattering florets on the wild plants each season to `domesticate’ the population. Conversely, if you harvest a non-shattering population by sickle, any shattering component falls to the ground and the population goes back to shattering. So it depends on method and intensity of harvesting and whether or not you retain harvested seed to sow.
I agree with Paul on the `several millennia’: there could in fact be reversals. And the `cultivation’ and `domestication’ criteria, while they work for much later on in the Neolithic, are almost impossible to delimit earlier on.
And seed size doesn’t always help. There are crops like barley, pearl millet and African rice where the seed-size stays the same long after they are obviously being cultivated. With problems over shattering and seed-size, there is not much left of the idea of `domestication syndrome’.