By twenty-eight thousand years ago, mysteriously, there was not a single Neanderthal to be found anywhere. How and why they disappeared so fast is the subject of much speculation, including the possibility that humans merely applied their superior weaponry to the situation and eliminated the competition. While there is scant but convincing evidence that the two species of hominids did have the occasional armed conflict, I personally don’t believe that humans “whipped their butts.” Neanderthals were excellent hunters and banded together. Defeating such a strong enemy time and again would have challenged even the most clever cohort of humans. It is much more likely that diseases did them in; humans’, to be precise. Mitochondrial DNA extracted from Neanderthal bone samples of a total of six individuals gathered from sites in Spain, Germany, Croatia, and Russia show that their own genome was remarkably homogeneous, only one-third as diverse as modern humans. This suggests that the Neanderthal’s immune system was also highly restricted. They would have been well suited to fight off microbial infections that they alone had encountered and evolved with, but the introduction of new microbial pathogens with different antigenic signatures and more powerful virulence factors from encroaching human populations out of Africa would have taken the repertoire of Neanderthal T and B cells by complete surprise. The result might well have led to the extinction of this last remnant hominid species, clearing the way for humans to repopulate that region, which they did.
Strangers in a Strange Land
It would not be the first time newly introduced infectious agents caused the extinction of a species. The natural history of the Hawaiian Islands is rich with examples of non-indigenous infectious agents that wiped out at least five genera of tropical birds through the introduction of bird malaria. The same kind of thing almost happened when the Spanish invaded South and Central America and unintentionally killed off nearly 90 percent of the 50 million native people there. The conquistadores exposed these unfortunate innocents to unfamiliar microbes, including influenza and the common cold, they brought with them to the New World from Europe. The result was near mass extinction. Before the Spanish gave up on their dream to establish new colonies in that part of the world, nearly 45 million people had perished. In exchange, the Spanish troops received the lasting “gift” of syphilis from indigenous populations, undoubtedly acquired through raping and pillaging sorties, which they then introduced into Europe. Syphilis is not as fulminating a disease as influenza, and therefore, Europeans died more slowly than the natives had, mainly from the neurological form of the infection. Since it is a sexually transmitted bacterial infection, many Europeans simply avoided syphilis by remaining faithful to their family unit.
Hunt, Gather, Sleep. Hunt, Gather,…
One thing is quite certain: Neanderthals were never farmers. The climate in most of northern and central Europe and eastern Asia did not favor an agrarian way of life. For one, the growing seasons were short and the availability of arable land was scarce. Second, there was no environmental need to invent farming, since they were cave-dwelling hominids who followed game animals during their migrations and lived off the meat well into the winter months by cleverly taking advantage of the freezing conditions outside to cache and preserve their food. Neanderthals did, however, collect wild grains and other edible plants from their immediate environment to tide them over through the lean times when game was in short supply. A portion of this natural harvest was bound to grow in greater abundance near where they lived, as some seeds—dropped accidentally in transit from collection site to cave or blown from stockpiles into the adjacent landscape—would have taken root in nearby soil. Nonetheless, despite this windfall profit of benign carelessness, Neanderthals did not cotton to the idea that growing plants for food was a good idea. When humans began to live in similar ways later on, it eventually “clicked” that by purposely or even accidentally dispersing some of the collected seeds into nearby fields next to water sources (i.e., environments in which these valued plants already grew), they could create a more reliable source of food.
In the Beginning
A recent archeological excavation led by Ian Kuijt and Bill Finlayson in Dhra, Jordan, near the Dead Sea, has shed new light on the origins of agriculture in that region. They uncovered a storage bin-like structure with the remnants of barley seeds and grindstones dating back to around 11,300–11,175 BP. These early farmers apparently collected wild seeds, grew them locally, and then used specifically designed tools for processing them into flour. The fact that they needed storage bins strongly indicates that they were highly successful agriculturists. This site predates by at least one thousand years the first-known site for farming domesticated grains.
Another discovery in that same region dates the domestication of barley to around nine thousand years ago. Farming, especially then, was hit or miss. When to plant and harvest had to be worked out for the very first time, and without the aid of an extension agent from the USDA or the Internet. Timing is everything. Enter the invention of the calendar, astronomy, mathematics, written language, and, last but certainly not least, religion. But this is getting a little ahead of the story.
On the Road
Life was looking pretty good up until about one hundred thousand years ago, when our ancestors were apparently forced out of East Africa by changes in climate that dried out the forests, turning them into semiarid grasslands and savannas. Perhaps this is also when hyenas entered the scene from an ice-bound Europe. Whatever the reasons, the results were clear enough. Humans first wended their way southward into what is now the Cape Town region of South Africa and hunkered down in caves up along the west coast, somewhere between what is now Namibia and Angola. The hyenas stayed the course in the Serengeti and settled into their present lifestyle, since their main source of food, the game of Africa, remained confined to that region of East Africa. Then, some twenty thousand years later, as ocean levels began to drop even more (around 400 feet) due to the onset of yet another ice age, humans somehow managed to escape out of Africa, perhaps by walking back up along the east coast to the Middle East, then to South Asia, into Asia, and eventually across the Bering Strait land bridge to the North American continent. In many places, they stayed and created permanent settlements, as harvesting local plants and hunting the readily available local game animals gave them a lifestyle they could settle down with and enjoy. In most centers where the invention of farming occurred, settlement of the region happened first, then farming arose, not the other way around, as logic might dictate. In other words, when humans finally established large gatherings of extended families, they apparently felt the strong pull of settlement life, with its many social advantages, and created a way to stay put and at the same time to accommodate a growing population that, without crops, might have exceeded the limits of the environment to feed. In fact, many early settlements did fail due to the lack of a reliable food supply, such as grains, that could be stored and used at a later time. Farming seemed like a natural outgrowth of that desire to remain connected. Humans are by nature gregarious. No wonder, then, that farming, once it developed, took hold in so many geographic locations. This all came about around ten thousand to twelve thousand years ago.
Great Minds Think Alike
There were six major regions of the world in which agriculture arose and then spread to adjacent areas over several thousand years: the Near Eastern Center, the Central American Center, the Chinese Center, the New Guinea Center, the South American Center, and the North American Center. Semidesert regions were favored sites for the invention of farming. Again, this flies in the face of logic. The most plausible explanation is that agriculture could be more successful in the absence of competitor bands of humans and large four-legged predators. The Anasazi in the Southwestern region of North America; the Nazca, Wari, and Incan peoples in South America; and of course the Hittites, Babylonians, Sumerians, and Egyptians all produced stable settlements, and many of them flourished for hundreds to thousands of years with farming as the basis for susta
ining them.
Good-Bye Biosphere, Hello Technosphere
Once farming became routine and reasonably predictable, we proceeded to convert much of the earth’s natural landscape into food production. History has recorded in a wealth of cultural expressions the progression of events regarding the evolution of settlements and cities; the emergence, flourishing, and eventual collapse of entire civilizations; and especially the relentless, irresistible growth of the human population. In the process, we systematically fragmented most of the world’s terrestrial biomes, rearranging the lives of countless assemblages of plants and animals and causing the extinction of many others. Ultimately, because all life on earth is connected in some way or another, even we became victims of our own penchant for severely altering natural systems. The loss of ecosystem services was the result. We found out the hard way just what nature provides for us, and free of charge: flood control, purification of the air, and regeneration of freshwater, not to mention the regulation of the earth’s temperature. In fact, the earth has been changed so much by our drive to commit more land to food production that, no matter where we look, there is abundant evidence of extensive ecological damage.
Technologies for sustaining food production from one year to the next—designing of irrigation schemes, food processing and storage systems, complex cuisines, development of astronomy and calendars to be able to predict the seasons, written languages, and organized religions—were in their earliest phases of development in many places around the world ten thousand years ago. All of these embryonic human urban centers were pulled together helter-skelter, ushering in the first of two major agricultural revolutions. However, farming arose somewhat more gradually than is commonly depicted in the history books.
As alluded to earlier, Neolithic communities at least two hundred thousand years ago were routinely harvesting and processing a wide variety of wild and abundant grains, including founder species for all major crops such as wheat, corn, millet, barley, and rice. There is ample evidence for this in numerous cave sites through Europe, Asia, and even South America. Most anthropologists believe that seasonal shortages of wild edible plants eventually led to the systematic management of these forerunner crops as a strategy to avoid overharvesting. Four examples will illustrate how pervasive and remarkably similar the development and practice of farming was, regardless of location or crops selected. It is almost as if someone had simultaneously turned on a switch in the “I want to be a farmer” part of our genome.
The Middle East Experience
Around seven thousand to eight thousand years ago, in the region dubbed the Fertile Crescent in modern Iraq, early attempts at growing food in large amounts in a sustainable fashion met with limited success, at best. That is because arable land was as scarce then as it is today, only occurring on the floodplains next to rivers such as the Tigris and Euphrates. Settlements throughout the region had access to wild grains and cereals such as barley, at least three kinds of wheat, and legumes such as chickpeas, beans, and lentils. As farmers gathered up these grains and seeds, then cultivated them under irrigated conditions, these founder crops grew weaker with respect to their ability to survive without our help, and at the same time became more nutritious, since the largest sizes of grains and seeds were selected for the next year’s planting. This is the process of artificial selection in its earliest practice. A few wry observers of the human condition have said that what actually happened was that wild plants in fact cultivated us by trapping humans into becoming totally dependent upon them for their very survival, thus ensuring the plants’ own survival in the process! This sort of a “you feed me and I’ll feed you” hypothesis of symbiotic relationships is an interesting twist on the practice of farming, to say the least.
Wastrel Society
But without any awareness of the need to practice methods that conserved the soil from year to year, the earth’s first farmers unwittingly allowed their crops to consume valuable nutrients without a thought to replacing them, and in doing so damaged the land beyond repair. Of course, these were the earliest of days. How could anyone possibly begin to understand the physiological needs of plants? Most believed that the gods—Tammuz and Nissaba (Babylonian), Osiris (Egyptian), Demeter (Greek), Saturn (Roman), Mama Allpa (Incan), Kukulcan (Mayan), Kokopelli (Anasazi), Hou Chi (Chinese)—were in charge of whether or not the crop would be good. Agricultural failures gave rise to whole religions; at the center of many was the belief that the community or some subset of individuals in that community had done something to offend those deities. To “correct” the problem and guarantee the next year’s harvest, sacrifices were often made, some of them at the cost of human life. Today, most farmers still pray for the essentials of what goes into reaping a bumper crop—just the right amount of rain, moderate temperatures, and lots of sunshine. In ancient times, as crops eventually failed due to lack of knowledge regarding anything to do with sustainable land use practices, farmers of the Fertile Crescent soon transformed that area into a desert by continuing to move their operations northward until they eventually ran out of floodplain altogether. That particular region of the Middle East still suffers from prolonged drought and the lack of nutrient-laden floods, thereby severely limiting any form of agriculture along those two famous river systems.
Egypt
In contrast, land along the Nile sustained farming throughout the millennia due to climatic conditions that ensured a more stable hydrological cycle associated with periodic flooding events. At various times throughout Egyptian history, farmers cultivated an incredibly varied array of vegetables and fruits, including garlic, leeks, onions, cabbage, lettuce, cucumbers, radishes, asparagus, legumes (peas, lentils, beans), olives, dates, and many herbs and spices. Many of the latter were used for medicinal purposes, as well. Nonetheless, even there devastating droughts produced crop failures, many of which are accurately recorded in ancient papyri and hieroglyphs. Egyptians even had a god assigned to watch over the growth of the vegetation (crops) and the weather, Osiris. They were superb observers of the natural world around them and drew heavily upon it for their belief systems. A good example is the lowly dung beetle. Also known as scarab beetles, these abundant insects were worshiped as the very givers of life itself. The beetles occupied a peri-domestic niche, dependent upon domesticated animals for a life-giving substance—dung. The life of this small insect was an open book, save for what happened underground. Many an Egyptian citizen saw them taking portions of common animal droppings, rolling them into a perfect sphere, and then, with their back legs, shoving the sphere down a hole they had dug. The next spring, out of the hole “miraculously” emerged a sprouting seedling, usually some kind of grass, and another beetle. How remarkable that life itself should arise from the very stuff that we discard after consuming life. To the Egyptian scholar, this sequence immediately suggested a mutually dependent cycle of sorts. Of course, the sun (Ra) was also deified, so the Egyptians may well have been the first ecologically savvy civilization, recognizing all the important connections needed to sustain life. They also invented a remarkable system of irrigation schemes to bring water from the Nile inland many miles, thereby extending their farming operations. Millions were fed from the grains and other produce carefully tended by a dedicated cadre of professional farmers.
Today, the flow of the Nile is severely impeded by the high dam at Aswan, which prevents the entire river basin from flooding and replenishing its banks with nutrient-rich silt once culled from the steppes of Sudan and Ethiopia during the rainy season up country. Modern irrigation projects and the extensive use of fertilizer have compensated for the loss and allowed farming to continue unabated in that desert region.
One other negative unintended consequence of the high dam has been the increase in the geographic range of schistosomes—waterborne parasites associated with agricultural practices in which human feces and urine are used as fertilizers. Once restricted to the lower Nile, the parasite’s intermediate host, a snail, has been able to extend its
range to the foot of the dam itself, thanks to the greatly reduced flow of the river. This parasite group causes life-threatening diseases that still persist in that region today, despite Egypt’s institution of sound public health practices aimed at its eradication.
The ecological damage incurred by farming in both the Middle East and Egypt has been extensive, and in the case of the Nile, preventing flooding has adversely affected even the sea life of the entire Mediterranean basin. Other regions have suffered similar fates for the same reason. In many cases, the result of ecological collapse due to poor farming methods has led to the fragmentation of cultures, or their extinction.
Mexico
Mexico is a major hot spot for the birth of agriculture. The origins of modern corn can be traced back to Balsas Valley in the south-central portion of that country. In 2009 agroarcheologists found strong evidence in the form of microscopic characteristically shaped starch granules at various sites in that region that pinpoint the origin some 8,700 years ago of the cultivation of maize, the parent precursor of all modern varieties of corn. Maize arose as the result of several related grasses hybridizing in nature to produce a plant that allowed for its cultivation in semiarid conditions.
Today’s corn is a keystone crop for many countries, including the United States. In 2007 the United States exported 63 million metric tons of corn, representing some 64 percent of the world market. That’s amazing when we consider that a mere eight thousand years ago we were just learning how to grow the stuff. Soon after its cultivation, maize became a staple food crop in many places throughout the New World, spreading northward to the Anasazi in the American Southwest and southward into South America to the Nazca, Wari, and later the Incas. More than 50 percent of the diet in most of these New World cultures consisted of maize and products derived from that crop, such as beer.
The Vertical Farm Page 4