A Short History of Evolution: Developing Agriculture in the Neolithic Era

This article is part of Carl Coon’s ongoing “A Short History of Evolution” series. Click here to read all entries in this series.

 

The Neolithic era began about 12,000 years ago, when our ancestors started to grow their food instead of hunting and gathering it. Cultural evolution began earlier, with the emergence of human intelligence (or intentionality), but was developing at a more stately tempo until agriculture and the domestication of animals came along and changed almost everything.  

Where and When It Began

Settled communities based on agriculture and animal husbandry first appeared in hilly areas north of the Euphrates, now parts of northern Iraq and Syria currently occupied by Kurds. Archeological evidence of settled villages goes back in that area to about 9,000 BC. The combination of naturally occurring grains, and animals that were relatively easy to domesticate, was more favorable there than anywhere else in the inhabited world. Farther east, other Neolithic settlements appeared a millennium or two later, starting in the Indus Basin and in central China. Each of these regions also harbored a combination of easily domesticated plants and animals that was almost as favorable as the first Garden of Eden in Iraq.¹ The trigger that started it all was climate change. Around 10,000 BC the weather changed dramatically for the better, so much so that we mark that period as the beginning of a new geological era, the Holocene. The planet warmed up, rainfall patterns settled down, and so did our ancestors. There's still some debate whether the new way of life evolved independently in each of the three areas or whether it spread from the first one. History and prehistory are studded with examples of cultural diffusion. However, the archeological evidence supports the idea that the three areas developed agriculture independently.  For one thing, the suite of grains and animals that were first domesticated is rather different in each of the three areas.² Once established, the new way of life spread rapidly. Some of the expansion involved absorption of resident hunter gatherer populations as the agriculturists took over their lands, but another common outcome was simple displacement, pushing the older populations back into less desirable turf. Our own takeover of North America from the existing Native American peoples was essentially a re-enactment of a drama that had been going on in many parts of the world for a dozen millennia. In virtually all cases, the odds were heavily tilted in favor of the agriculturalists, because there were generally a lot more of them when push came to shove.  

Who Invented Agriculture?  

Who first selected wild grains and domesticated them? We know that before the Neolithic era, people sometimes gathered the seeds of wild grains and used them for food. The problem with wild varieties is that their seeds ripen at different times so that they don't all get broadcast at once. So people (usually women) had to go through fields and shake the ripest pods, which was a time-consuming method. Some genius (probably a woman, see above) started saving seeds from the relatively rare stalks that did all pop at once, and replanted them. It worked, and agriculture was born.  

A Major Turning Point

If you think of evolution in terms of increasing complexity and the concentration of power, agriculture was a major turning point. In natural selection, the food supply normally operates as the most important single limit on population growth. Remove that limit and population can increase in a geometric progression. And it did with people when agriculture provided a reliable new source of food. But that was only the start. A fertile region could support a much larger population by farming than by hunting and gathering, but in a few generations the population would multiply and something would have to give. When the Neolithic world was still young the most obvious answer when there wasn’t enough land any more was to move on into fresh territory, and of course that happened and explains the rapid expansion of the Neolithic way of life throughout Eurasia and even into the New World. This is how biological evolution works. But in our case there was another dimension to the process, cultural evolution. The uniquely human capacity for intentional thinking enabled our forebears to adapt much more rapidly to new environments and new circumstances. And it enabled the people who stayed behind, when the young folk wandered off in search of new land, to grow and prosper as well.  

Necessity is the Mother of Invention

Both the pioneers and the stay-at-homes faced many challenges as they went about colonizing the planet. Say the problem at hand was cycles of flood and drought that kept interrupting the food supply. One solution was granaries to store enough food to carry people through droughts. But any such adaptive changes would spawn new challenges requiring further adaptations. Humanity found itself on a kind of treadmill, with one thing leading to a couple of other things, an accelerating process seemingly without end. If we want to know how we got on to that treadmill during the Neolithic era, we need to look beyond the immediate causes and into what happened to the basic nature of the evolutionary process itself. For starters, how does one characterize the ‘invention’ of agriculture? It wasn't natural selection, it was intentional. It wasn't really cultural selection, nor was it a product of group selection. It seems to me that if there is a force or principle that operates to make an important evolutionary change happen, we have an example of it here. You don't need divine intervention, you need a convergence of factors that create a potential market for something that doesn't yet exist, at least in any visible form, and a convergence of existing entities that have the potential of getting together and meeting that emerging need. That convergence of factors, if strong enough, can vastly improve the prospects for a particular kind of variant in the system, making it not only viable but eminently desirable. And then that lucky variant may get discovered. It's as though the planet had a big computer, capable of finding a very small needle in a very big haystack, scanning for some as yet unknown thing. Can that convergence of factors increase the odds that the lucky variant will be found? If so, can this kind of event help us understand how the human intentional mind got started? Could its principle also help explain the emergence of the first life out of our planet's primordial soup? If agriculture did start independently in three different places, then it provides a kind of laboratory for testing theories of how major evolutionary breakthroughs emerge. We could look, for example, for similarities and differences that might shed light on the relative importance of environmental factors. Is it too much to hope that such studies might prove useful for cancer research, or conflict resolution, to take examples at opposite ends of our history of evolution? Tags: A Short History of Evolution