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The History of Humanity
A few days ago I stood on a rock outcropping near the summit of Mt. Hood, Oregon. As I gazed across the evergreen forests, meadows and alpine lakes and streams below me, a light wind murmured through the fir boughs. I felt as If I had always been in a place like this, if not here, then somewhere else like it in some other time. I felt the desire to leave this mad modern world behind and just live how humans have lived for eons, in nature. Could I, I wondered, simply walk off into this spectacular wilderness, leaving the modern world I knew too well, and live as my human and pre-human ancestors had for thousands, nay, millions of years? To actually do so would mean giving up many luxuries that we in this current time have become accustomed to. How would I construct a shelter, secure my food, and endure the coming weather. Overwhelmingly self confident, I felt certain that if I had to do so, that I could indeed survive.
All my life I have been a student of sciences, history, and human nature. I am confident I could find food, build shelter and survive alone in this wilderness if I had to, but rarely in history have humans lived alone in the world. We are, and always have been, social animals. Six-million two-hundred thousand years ago our ancestors stood upright, walked as we do, and used tools and weapons to survive in their homeland of the changing environment East of the Great Rift Valley in central Africa. These proto-humans did not live alone. Our distant ancestors were social creatures as we are. They did not live solo like orangutans or sea turtles do, only uniting with others of their species to mate and then return to a solitary existence. They survived in groups, families, packs, tribes or clans, but almost never alone; they did so because they had to. Living in numbers meant relative safety from predators, cooperation in hunting and efficiency in gathering. There existed in this ancient past not one but many types of hominins (upright walking, somewhat big brained, tool using primates). They were genetically diverse and radiated in their adaptation to different food sources and environments. Populations of these hominins rose and fell in numbers throughout history. Many species died off as our own branch of the human tree nearly did. More than once our species dwindled to only a thousand or fewer. Far fewer numbers than we would label “endangered” today, yet together, in small bands, we survived and intermittently flourished. In the fullness of time hominins spread out across their home continent. It is widely agreed that one of our earliest hominin ancestors were the Australopithicines that arose in Central Africa at least 6.2 million years ago (mya). They appear to have evolved into Homo Erectus 1.8mya, the first of these migrated out of Africa at least 1.5mya into the Middle East, through India and China by 1.3mya, and as far as Indonesia .9mya. Their remains are found from later migrations in Southern Europe .75mya. By 70,000 years ago (ya), Homo Erectus appears to have died out, most likely being killed off by the “Toba Catastrophe”.
About 73,000ya, in Sumatra, Mount Toba erupted as a supervolcano. It was the largest volcanic event in over 2 million years. The Mt. Toba eruption is estimated to have been 30,000 times more powerful than the Mt. St. Helens eruption in the U.S. in May of 1980. Toba launched 2800 cubic kilometers of ash and Sulfuric compounds into the atmosphere which rapidly caused a worldwide temperature drop of up to 25 degrees F. The Earth’s population of Humans was estimated to be about 1 million before the catastrophe, but plunged to only about 30,000 individuals (3%survival) in the following few years. This “volcanic winter” effect precipitated severe climatic changes that caused a drought that lasted through 6 to 10 years with extremely cold temperatures and low sunlight. This was followed by an ice age that lasted an estimated one thousand years more.
Homo Neanderthalensis lived from 400,000 to 28,000 ya. They, as we did, survived Toba. Their range included the Middle East, current day Spain and Portugal, and Southern Europe as far North as the Southern tip of Britain. These were the first Europeans, true pioneers. In time climatic changes cooled the planet and isolated these humans in an ice age Europe. Only when the climate warmed again would the next wave of humanity venture forth from the African homeland. Neanderthals appear to have interbred with Homo Sapiens when they migrated into the Middle East, after the Toba eruption. Homo Sapiens and Neanderthals coexisted for some 12,000 years in Europe, between 40,000 and 28,000 ya. Modern humans of non-African origin bear 1 to 4% of their DNA from Neanderthals as a testament of this interbreeding.
When that ice age ended 40,000 ya, our species again surged outward from the African homeland to inhabit nearly every imaginable environment on the planet. Throughout these millions of years of migrations in varied ecosystems, humans adapted to surviving on whatever food fare nature offered. Over the millennia we hunted and foraged, leaving behind the evidence of our passage. Shell fish, giant sloths and bears, mammoths, bison, even the great whales were hunted by primitive humans using only our wits and hand-crafted tools of wood, leather, and stone. But, for all of our great killing prowess, there is one creature we did not kill in great numbers, other humans. That is, until relatively recently in the history of our species.
In a broad swath of land across the Middle East, today referred to as the “Fertile Crescent,” our ancestors began to regularly process and consume primitive grass seeds. Besides containing the embryo of the next generation of that plant, seeds also contain the small store of carbohydrate that will nourish the tiny seedling as it strives to establish itself in the soil. A fibrous husk surrounds and protects the embryo and the carbohydrate rich energy source that the growing plant will derive sustenance from, much as a growing bird embryo draws its fuel from the yolk it carries in its eggshell. Humans had consumed grass seeds before, there is evidence of it being processed by milling as far back as 60,000 years ago at some archaeological sites in Africa, but beginning only some 12,000 years before our present time something different transpired in the Middle East. Probably unintentionally, we began breeding these grasses.
As Earth’s climate warmed from another brief ice age 12,000 ya, known as the Younger-Dryas, the polar ice caps melted significantly, for a time rainfall was increased. This created a burst of plant life in the fertile crescent. A variety of plant known as Einkorn wheat, an ancestor of our modern wheat, had cross pollinated naturally with another species known as “goat grass” in the Middle East some 30,000ya to produce a larger seeded grass called Wild Emmer. Wild Emmer is what hunter-gatherers began to cultivate in the fertile crescent following the Younger-Dryas which lasted from 12,800 to 11,600ya.
Naturally, the gatherers of that time tended to collect those grasses with larger seed heads. During cleaning and milling some seeds would be scattered and grow naturally near the human settlements. Of these larger, more carbohydrate dense plants, humans may have again selected those with the largest seed. Some of these plants would experience a rare, but normal, type of mutation called polyploidy. In polyploidy as the initial cell divisions of the plant embryo occur, one of the cells receives double the usual number of chromosomes while the other cell receives none of the DNA and dies, leaving its sister cell to proceed and develop with double the normal amount of genetic material, producing a larger more robust plant and seed.
Our modern grains such as wheat and barley evolved into the bulging seed heads of the modern cereal crops we know today with their abnormally high concentration of carbohydrates that gave our predecessors many distinct advantages as a result of humans selectively breeding them.
Humans utilize energy from three types of fuel “reserves” within the body. These three sources can be visualized as a series of gas tanks that may be used in varying amounts in succession or combination and correspond to the major categories of foods that we consume: protein, fat, and carbohydrate. Fat and protein must be converted into carbohydrate to be utilized by the mitochondria that inhabit each cell of the body and provide the energy necessary to power muscle contraction, nerve conduction and all types of metabolism required by the body. When it is readily available in the bloodstream, carbohydrates can provide sudden bursts of energy that offer the person (or animal) a distinct advantage when facing a high energy demanding task such as fleeing from threatening situations or chasing down prey. But by far the greatest advantage these seeds offered to ancient humans was a fuel source that could be harvested in a very short time span and then stored for a year or more to provide a supplement or substitute energy source during periods of
