The Birth of Agriculture: Migrating for the world

Graphs showing the likelihood
of agriculture originating in
that region. Demonstrating
demic migration of agriculture
practices.
Source: Pinhasi et al 2005

As I eluded to in my previous blog, agriculture didn’t originate in one single place, but actually in several different areas, mainly though the Eastern Sahara, Southwest China and most importantly the Near East. So, how did agriculture spread?

Within the literature there has been two theories proposed called, cultural and demic diffusion, where the former relates to the movement of agricultural tools and ideas, whereas the latter relates to the movement of farmers from these sites of origins (Cavalli –Sforza 1996). Methods such as gene frequency and language have been used to try and model the dispersion of agriculture, with a focus on SE Asia and the Near East (Cavalli-Sforza 1996; Renfrew 1996). Pinhasi et al(2005) shows that 20% of the European gene pool is shared with Near East, with that value reducing as one reaches North West Europe. This seems to indicate an initial migration of farmers from the Near East across environmental corridors at a speed of roughly 0.6-1.3km/y, all of which is consistent with a demic diffusion of agriculture (Pinhasi et al 2005). 

This is reflected in Southwest Asia by Renfew (1996) which also showed a strong genetic cline originating out from the ‘nucleus of origin’. Not only that, but he also noted the movement of languages across Europe and Asia, of which seems to show similarities to that of the ‘nucleus’. Both of these conclusions line up with the diagram constructed Bar-Yousef (1998) which depicts the movement and time frame of agriculture during the Holocene. All of this evidence seems to solely point towards demic diffusion.

A Map showing the 'nucleus origin' and expansion routes of agriculture
Source: Bar-Yousef (1998)

Though this might not occur unless the conditions are favourable to allow migration, which usually involves the saturation of the existing population and the suitability of the dispersion destination, which is often controlled by the society itself and the local environment  (Renfrew 1996). A nice example regards cattle in the Eastern Sahara, although this is the nucleus of cattle domestication (9.5 kyra), they weren’t shown in the Nile Valley record until the introduction of Near Eastern Cattle around 5.9 kyra (Garcea 2004). Why might this have been the case? The technology was already there, though the climate didn’t facilitate a safe dispersion until a more humid climate occurred, providing a corridor to cross the desert (Garcea 2004). 

Rock Wall Art from the Sahara showing the domestic use of cattle
Source: Garcea 2004

So not only has climate been designated as a leading factor in the birth of agriculture in the ‘nucleases of origin’, but it has also been shown to be an important factor in allowing the farmers migrate to new areas and societies which allowed the spread of agriculture. On top of all that, climate has been shown to be a powerful agent in shaping and pushing settlements into complex societies through mediums like agriculture and harsh environmental conditions. So now it is time to start showing you some examples of how climate affected the birth, fall and cultures of some civilizations.