Following the rapid advances in our understanding of genetics in recent years a new branch of biological history or biohistory has emerged, where human history is seen through the prism of genetic changes and the theory of evolution. For my long essay Why Did Europeans Create the Modern World? I included biohistory as one of the aspects explaining different levels of accomplishment, informed especially by the book Understanding Human History by the American astrophysicist Michael H. Hart, which is available online as a pdf file. Another recent title is The 10,000 Year Explosion: How Civilization Accelerated Human Evolution by Gregory Cochran and Henry Harpending from the University of Utah in the United States.
Evolution proceeds by changing the frequency of genetic variants known as “alleles.” An allele is one of two or more versions of the same gene. The advent of agriculture vastly increased the total amount of food available, as humans didn’t merely have to rely on food readily available in nature but could grow their own in addition to this. The larger and more permanent settlements associated with agriculture gave birth to new infectious diseases, as a critical mass of humans lived in close contact with each other and with domesticated animals and their germs. Food production allowed for the accumulation of wealth, trade specialization and the rise of nonproductive elites, who ruled others simply because they could.
Agriculture allowed those who practiced it to greatly expand their numbers, but it is distinctly possible that the nutritional quality of the food of early farmers was initially worse than that which had traditionally been available to hunter-gatherers. Consequently, the health of each individual was not necessarily better in the Neolithic period than it had been in the Paleolithic era. The bodies of those who practiced agriculture had to adapt to a new diet consisting of foods that had either not been eaten before or had previously been of only minor importance.
According to The 10,000 Year Explosion, “For example, we see changes in genes affecting transport of vitamins into cells. Similarly, vitamin D shortages in the new diet may have driven the evolution of light skin in Europe and northern Asia. Vitamin D is produced by ultraviolet radiation from the sun acting on our skin – an odd, plantlike way of going about things. Less is therefore produced in areas far from the equator, where UV flux is low. Since there is plenty of vitamin D in fresh meat, hunter-gatherers in Europe may not have suffered from vitamin D shortages and thus may have been able to get by with fairly dark skin. In fact, this must have been the case, since several of the major mutations causing light skin color appear to have originated after the birth of agriculture. Vitamin D was not abundant in the new cereal-based diet, and any resulting shortages would have been serious, since they could lead to bone malformations (rickets), decreased resistance to infectious diseases, and even cancer. This may be why natural selection favored mutations causing light skin, which allowed for adequate vitamin D synthesis in regions with little ultraviolet radiation.”
Alcoholic drinks, which became important with the rise of agriculture, have plenty of bad side effects, yet essentially all agricultural peoples enjoyed some form of alcoholic brew. The consumption of fermented beverages containing modest amounts of alcohol could be beneficial to your health as drinking wine or beer provided some protection against waterborne pathogens. For this reason, alleles that reduced the risk of alcoholism prevailed among agricultural populations in Eurasia. Many of those who did not have extensive food production before the modern era, such as Australian Aborigines, Eskimos or Native Americans in North America, are particularly vulnerable to alcoholism and have special health problems more frequently than others when exposed to a Western diet.
Before the rise of agriculture no one past infancy, the first years of our lives when we drink human breast milk, could digest milk sugar, or lactose. Lactase is the name of the enzyme that allows us to digest the complex milk sugar. After cattle were domesticated, cow’s milk became a nutritious addition to the diet. Several different populations, all raising cattle or camels in Europe, East Africa and the Middle East, independently evolved the ability to digest milk for life. Genetic evidence indicates that such a mutation probably first occurred in central Europe, perhaps before 5000 BC. Pioneer farmers in northern Europe used crops from the Near East that were not necessarily ideally suited for a cooler, northern environment, and cow’s milk may have become an increasingly important staple for survival in these regions.
Lactose intolerance is found among just 5% of Scandinavians in the far north of Europe, but among more than 70% of the population in Sicily in the far south. While it is common to show some symptoms of lactose intolerance, many Africans and Asians are not able to digest lactose at all. “Which came first, the cattle or the mutation, you can’t tell,” Harpending says. “If the mutation had not occurred, there wouldn’t be so much dairying. But if people who could digest lactose didn’t have cattle, the mutation would have had no advantage.” He speculates whether this mutation may have contributed to the first Indo-European expansion.
When cattle were kept at least as much for their milk as for their meat this was beneficial, since dairying is more efficient than raising cattle for slaughter; it produces about five times as many calories per square kilometer. Those who could utilize milk as adults could raise more warriors on the same amount of land. Dairying could have been more productive than grain farming in northern regions during the late Neolithic and Copper Age/Early Bronze Age. As the Proto-Indo-Europeans became dairymen they relied more on cattle and less on grain farming, which gave them a major advantage in mobility over more settled populations of pre-state farmers. Perhaps the first Indo-Europeans were a successful society of pastoral nomads who raised livestock and moved about to find good pastures for their animals.
The archaeological Pit Grave or Yamna culture north of the Black Sea from around 3500 BC is according to the Kurgan hypothesis of Marija Gimbutas often identified with speakers of PIE. The name comes from the low mounds, or kurgans, in which they often buried their dead. They appear to have been primarily pastoral nomads who practiced some agriculture. Interestingly, the bodies found in Kurgan burials seem to have been taller than was common in those days, which indicates that these people were more physically fit than their neighbors.
Gregory Cochran and Henry Harpending picture the IE expansion as beginning with a very rapid spread across the steppe as soon as the increased frequency of the lactase-persistence mutation became common enough to allow the switch to a dairying economy. Their increased mobility aided the development of a successful warrior society. The authors believe that “the Proto-Indo-Europeans were rather backward in the realms of technology and social complexity. Sumerians invented the wheel, writing, and arithmetic and had cities and extensive irrigation systems at a time when the Proto-Indo-Europeans had, at most, domesticated the horse. We suggest that the advantage driving those Indo-European expansions was biological – a high frequency of the European lactose-tolerance mutation.”
There is some basis for this hypothesis. Drinking milk from cows, horses or camels was a shared trait among many conquering peoples, from Arabs to Mongols. Nomads of the steppes remained a serious threat for thousands of years. Only strong states could provide some protection against them, and even they occasionally failed. The Chinese did not consume milk, but some of the nomads in Central Asia did. The settled lifestyle in China seemed incomprehensible to the Mongol conquerors in the thirteenth century, with so many people and so few animals compared to their homeland in Mongolia. To them, the peasants were like grazing animals rather than real humans who ate meat and drank milk. They referred to grass-eating (cereal-eating) people with the same terminology that they used for cows.
In Commentarii de Bello Gallico (Commentaries on the Gallic War), Julius Caesar provides a personal account, written as a third-person narrative, of the Gallic Wars in France, Belgium and parts of Switzerland and the first Roman incursions into Britain, including the victory over the Gallic army led by chieftain Vercingetorix in 52 BC. Although written to boost Caesar’s personal standing in Rome and reflecting the traditional disdain for non-Roman “barbarians,” the text nevertheless contains useful bits of historical information. While writing about one Germanic tribe, Julius Caesar mentions that they did not live on grain as much as on meat, milk and cheese and suggests that this diet helped to make them tall, strong warriors:
“They do not live much on corn, but subsist for the most part on milk and flesh, and are much [engaged] in hunting; which circumstance must, by the nature of their food, and by their daily exercise and the freedom of their life (for having from boyhood been accustomed to no employment, or discipline, they do nothing at all contrary to their inclination), both promote their strength and render them men of vast stature of body.”
Lactose tolerance may well present one piece of the puzzle, yet contrary to what Cochran and Harpending seem to believe it is far from certain that the wheel was invented in Sumerian Mesopotamia. A marked shift can be detected in the archaeological record between 3500 and 2500 BC in some regions of Central and Eastern Europe north of the Black Sea, with the so-called Pit Grave and Corded Ware cultures. Later the Bell-Beaker complex included much of Western Europe in this new continent-wide configuration of Bronze Age Europe which had begun in the mid-fourth millennium BC. There are many scholars who suspect that this shift was closely related to the first, great wave of the Indo-European expansion.
Current opinion suggests that it was around the middle of the fourth millennium BC that wheeled transport first appeared, stretching across a vast interconnected region from northern Germany and southern Poland via the Black Sea to Mesopotamia, beginning around 3500 BC.
As scholar Philip L. Kohl says in The Making of Bronze Age Eurasia, “It is shortly after the introduction of wheeled transport that evidence for its massive utilization on the western Eurasian steppes is documented in the excavation of scores of kurgans containing wheeled carts with tripartite wooden wheels. These were not the chariots of a military aristocracy but the heavy, ponderous carts and wagons of cowboys who were developing a form of mobile Bronze Age pastoral economy that fundamentally differed from the classic Eurasian nomadism that is later attested historically and ethnographically.”
This innovation spread very rapidly, which makes it harder to establish its origins, yet the earliest secure evidence of wheeled vehicles we currently possess comes from Europe. The people who spoke Proto-Indo-European had their own terminology for axles, shafts and yokes. The PIE word for “wheel” relates to words for “to turn, spin,” whereas “wheel” in Sumerian appears to be a loanword from Indo-European. It is not uncommon in the modern world to borrow words for borrowed technology, which is why many non-Western languages use words similar to “telephone.” The same principle presumably applied in ancient times.
If wheeled vehicles were invented by prehistoric Europeans, which is not a certainty but a real possibility, this would constitute one of the first instances when a revolutionary innovation of global importance spread from Europe. It was not to be the last. Bicycles, automobiles and other means of transport were created in modern Europe. If the first wheeled carts, too, were created on this continent in the fourth millennium BC then this would imply that almost all prototypes of the basic forms of wheeled transport during the past six thousand years have been invented by Europeans. The only possible exception is the wheelbarrow, which may have been invented by the Chinese, yet the history of this device is not beyond dispute.