Origin Story: A Big History of Everything

by David Christian

The species that flourished best were those that pleased humans, because those were the species humans looked after most carefully. More nutritious plants, such as domesticated wheat and rice, evolved, as did more helpful animals, such as domesticated dogs, horses, cattle, and sheep. Domesticated animals helped hunters, carried and hauled people and goods, or provided wool or milk. When slaughtered, they provided meat, skins, bones, and

But in return for their chopping, plowing, weeding, draining, and fencing, they got a lot more energy and resources from the land, rivers, and forests that surrounded them, because the species they valued flourished spectacularly. That allowed the first farmers t...

Put simply, farming was an energy and resource grab by a single, very resourceful species with access to increasing amounts of information about how to exploit its environment. Through the magic of collective learning, humans had discovered how to increase their share of the energy and resources flowing through the biosphere by diverting more and more of those flows to human uses, just as humans would eventually channel major rivers onto their own fields and into their own cities. To a biologist,

Foragers used and knew about hundreds of different species of plants, animals, and insects, but farmers focused on a small number of favored species, so they developed exceptionally intimate relationships with them. Intense symbiotic relationships often lead to changes in the behavior and the genetic makeup of both species. Modern honey ants “domesticate” aphids. They protect the aphids, provide them with food, and help them reproduce. Now the aphids have changed so much that they can no longer survive on their own. They pay for food

More familiar and more important to us is the relationship between plants and bees. Bees get nectar, and the flowers reproduce more reliably because the bees carry their pollen from flower to flower.

The favored species on which farmers lavished so much care and work (the domesticates) gained little in quality of life. But they did well demographically. Their numbers soared, while the number of wild animals (the animals farmers were not interested in) plummeted. In the year 2000, the total biomass of all wild land mammals was about one-twenty-fourth that of domesticated land mammals.1 Symbiosis

Compare a modern ear of corn with teosinte, its bedraggled wild ancestor. Or compare a wild mouflon sheep with its modern, domesticated relative. The domesticated animal looks almost as if it had evolved to please humans. It is docile (some might say, unkindly, that it is stupider than its country cousins), it produces more wool than it needs, its meat is tasty for humans, and

Demographically, this is a surprisingly successful evolutionary strategy. Today there are more than one billion domestic sheep but just a few...

For the most part, though, humans adapted to the symbiotic relationships of farming not with genetic changes but with new behaviors: technological, social, and cultural innovations accumulated through collective learning. They developed new ways of working the land, woodlands, and rivers. And as they did that, they had to learn new ways of collaborating and living together. Cultural change happens much faster than genetic change, and this explains why farming transformed human lifeways within just a few generations.

last ice age severed links between Eurasia and the Americas, and there was hardly any communication between Eurasia and Australasia or with the islands of the western Pacific, some of which were settled as early as thirty thousand years ago. In effect, humans now lived in a number of separate world islands or zones. Within these zones, human history played out almost as if the inhabitants were living on different planets. The largest and oldest world zone was Afro-Eurasia.

because there was a land bridge between Africa and Eurasia, ideas, people, and goods could move in relays over vast distances. The next-oldest world zone was Australasia, first settled about sixty thousand years ago. The Australasian world zone was connected to Papua New Guinea and Tasmania during the last ice age but had the most tenuous of connections to Eurasia.

world zone, in the Americas, was settled at least by fifteen thousand years ago but was largely cut off from Eurasia when the Bering Strait was flooded at the end of the last ice age. In recent millennia, a fourth zone would emerge in the Pacific. Western islands such as the Solomons may have been settled as early as forty thousand years ago, but islands farther to the east and south (including New Zealand, Hawaii, and Easter Island) were settled durin...

suggests something very important: as independent human communities accumulated more technological and ecological knowledge, there was a high probability, wherever they were, that they would eventually use the knowledge they had accumulated as foragers to develop farming techniques. But they were likely to do so only if they needed the extra resources that farming could provide because, after all, farming was hard work and it meant changing a community’s entire way of life. Why Did Humans Take

conditions for the entire agrarian era. Graphs of average world temperatures over the past sixty thousand years show clearly the remarkable climatic stability of the past ten thousand years, even though variations were greater away from the tropics. The warmer, wetter climates of the early Holocene created a few regions of abundant and diverse plant life that formed rich “Gardens of Eden” for local foragers. In some of these regions, resources were so abundant that foragers could settle down in permanent communities or villages. Recently, nine-thousand-year-old circular stone houses have been found on the Dampier Archipelago, off the coast of Western Australia.3 Similar changes have been studied most closely in the Fertile Crescent,

That’s why, in most sedentary communities, women were expected to bear as many children as they could, partly because they knew that perhaps half would die before they reached adulthood. Such attitudes sharpened differences in gender roles and ensured that most women’s lives would be dominated by the bearing and rearing of children throughout the agrarian era of human history. The same rules explain why, within a few generations, many villages

As populations grew, the Natufians had to extract more resources from the land. That meant grooming the land more carefully, and eventually it meant taking up some form of farming. The Natufians were falling into a honey trap. They had built their first villages in what seemed like an ecological paradise, but within just a few generations, they faced a new population crisis, and because neighboring communities were also growing fast, they could not just use more land. Instead, they had to use whatever tricks they knew of to increase the productivity of the land they already had. These pressures pushed them, probably reluctantly, into the tough life of farmers, and as they learned what it meant to be farmers, they forgot what it meant to be foragers. As always with collective learning, the

summary, warmer climates made village life and farming possible in a few favored regions, population pressure sometimes made it necessary, and the reserve knowledge accumulated by foragers over many millennia provided the start-up technologies for the first farmers. The geography

evolutionary psychologist Robin Dunbar is right that evolution equipped human brains to cope with groups of no more than 150 individuals, it follows that communities much larger than this would need new social technologies to hold them together. During the first half of the agrarian era of human history, most farming villages were independent communities with limited ties to neighboring villages and small enough to be held together through traditional kinship rules. Though exchanges of people, goods, and ideas between villages were increasingly important, there were not yet any states, empires, cities, or armies. The huge, complex societies that have dominated the last five thousand years of human history appeared only after farming had spread far and fast enough to create a critical mass of people, resources, and new technologies. But the roots of agrarian

For better or worse, human history had entered a more dynamic era in which change was the one constant. As human communities grew in numbers, size, and complexity, they laid the foundations for the agrarian civilizations that have dominated the past five thousand years of human

Jericho, one of the oldest sites of continuous settlement anywhere in the world, was first settled in Natufian times because it had a well that never ran dry. By nine thousand years ago, Jericho had evolved into a town of perhaps three thousand people. As towns grew, some offered new services, jobs, and goods. More people were lured to them, and over time

The southern Mesopotamian city of Uruk is often described as the first city in human history. It was a port on the Euphrates River. Like most Mesopotamian cities, it depended on complex, well-managed irrigation systems fed by the major rivers. But it also bordered the swamps of the southern river delta. Indeed, it may have grown in a period of drying climates, which forced people from outlying villages to migrate into the cities with their well-maintained irrigation systems. Fifty-five hundred years ago, Uruk had a population of ten thousand people living on opposite banks of the river Euphrates.