Scientists tell us we are all one species, all seven billion of us, descended from an Adam and Eve who walked out of Africa some 50,000 years ago with fully modern brain size, articulate language and all the other human characteristics. There are no other branches on the human family tree. The last pre-humans have now been extinct for 30,000 years. We are all Homo sapiens. We can interbreed, and do.
If you're like me, you've listened out of respect for science but privately thought "Yeah, well, nice theory, but maybe over-simplified. What about Australian Aborigines, or those little guys in New Guinea?" Touchy questions. They feel politically incorrect in a vague way and are rarely discussed. Actually, it turns out that scientists welcome skeptical questions. Their answers may surprise and fascinate you.
Let's start with the most obvious difference between people: skin color. When your sweet Sunday School teacher, safely wrapped in her privileged white skin, told you "we are all the same people under our skin," she was basically right. But her benevolent tone might have been more reflective had she known the full story of her ancestors' color...
Five million years ago, when we started out as mostly chimps covered in fur, we had pale skin under our fur. Then, when we walked naked under the African sun for millions of years, our skin turned very black. We were black when we became fully modern humans and left Africa. We were still quite dark when we fought the Neanderthals and populated the world. The artists who created magic in Chauvet cave probably still had dark skin. Finally, by 15,000 to 20,000 years ago, many of us turned pale again after thousands of years in northern latitudes. (Pale skin lets in more sunlight, required for the body's synthesis of vitamin D.)
Other differences have evolved within the "Family of Man" since we left Africa 50,000 years ago. Some, like body size and facial features, are obvious; others are less so, like reactions to drugs, lactose tolerance, etc. I'll let Charles Darwin himself explain how this happens:
"Let us suppose the members of a tribe... spread over an unoccupied continent (and) soon split into distinct hordes, separated from each other by various barriers and still more effectively by the incessant wars between all barbarous nations. The hordes would thus be exposed to slightly different conditions and habits of life, and sooner or later come to differ in some small degree. As soon as this occurred, each isolated tribe would form for itself a slightly different standard of beauty, and then unconscious selection would come into action through the more powerful and leading men preferring certain women to others. Thus the differences between the tribes, at first very slight, would gradually and inevitably be more or less increased." (From "The Descent of Man," 1871.)
Natural selection and sexual selection, as Darwin described, work slowly and progressively. Mutations, on the other hand, occur in a single birth. To propogate throughout a population, however, mutations must be so favorable as to confer a "reproductive advantage" (resulting in more offspring than normal), and be inherited. If not, they're lost in the every-generation shuffling of genes. During our brief 50,000 years, humans haven't had any major mutations, so the racial differences we've evolved are very minor. We are a long, long way from splitting into separate species. All human races have the same brain size and inherent capabilities.
Basically, your Sunday School teacher was right, but millions of caucasians don't really believe that human races are equal. Even Darwin's friend and fellow researcher, Alfred Russel Wallace, concluded that "The intellectual and moral, as well as the physical, qualities of the European are superior..." This racist belief has caused endless conflict and suffering, but it seems to be based on overwhelming evidence: white Europeans did, in fact, conquer most of the world in the last 500 years.
So, if Caucasians aren't smarter or "more evolved" than other races, how did they manage to become world conquerors?
Modern history classes attempt to answer this politically awkward question by teaching that Europeans had ships, guns, writing, metal weaponry, plus European diseases (which proved to be the most devastating weapon of all). Which is not wrong, but it's also not the real answer.
First, let's start with a very brief recap of the most dramatic conquest, that of the Americas.
Humans first came to the Western Hemisphere from Siberia at least 12,000 years ago, when retreating ice caps exposed a "land bridge" between Russia and Alaska. Rising sea levels then submerged the bridge, leaving a growing population in the Americas totally isolated. By 500 years ago, two great civilizations dominated the Americas: the Aztecs in Central America and the Incas in Peru, each having populations of millions of people.
Both empires fell to Spanish conquistadors within 50 years of Columbus's arrival in the West Indies. Hernando Cortes dismantled the entire Aztec empire within two years of his arrival in 1519. In 1532, Francisco Pizarro defeated the Incas in a decisive battle at Cajamarca.
Cortes had only 550 soldiers; Pizarro had just 168. Both, however, had guns, steel swords and horses. The Incas had recently discovered bronze, but like the Aztecs, were mostly still armed with stone age weapons -- of little effect against mounted soldiers protected by steel and chain mail armor and steel helmets.
The spaniards' literacy played a role as well: neither Aztecs or Incas had any knowledge of guns or conquistadors (and their intent), and they initially perceived a man on a horse as a magical man-beast. In contrast, both conquistadors had extensive information about American natives from their already-established West Indies colonies. Pizarro also had detailed written reports about the Aztecs from Cortes, perhaps the boldest expeditionary leader of all time ("pretend to offer friendship... capture their ruler... divide and conquer...").
Both Aztecs and Incas soon learned they could first kill the horses and then the soldiers, but it was already too late: by then, they had been slaughtered by the thousands, their leaders were dead, and the conquistadors had concluded deceitful but effective pacts with their native American opponents.
Meanwhile, European diseases had immediately begun their deadly work. In 1520, while the Aztecs were still trying to repulse Cortes, a smallpox epidemic wiped out thousands, including Cuitlahuac, the ruler who succeeded Montezuma, who had been killed by Cortes.
In addition to smallpox, the colonizing Europeans carried typhus, measles, influenza and bubonic plague, other diseases for which the native Americans had no immunity. These diseases advanced faster than the Europeans themselves, ultimately killing 80 to 95% of the total population of native Americans from Alaska to Tierra del Fuego. On their side, Native Americans had only malaria -- not nearly enough.
That was how it happened.
Which, of course, doesn't answer the real question: why was it that non-Europeans were still living as stone age people, with low resistance to diseases, while Europeans wound up with technology, literacy, and disease immunity?
Why didn't it turn out the other way around? If both populations started off as equally modern humans when they separated 12,000 years ago, why was it that the Incas weren't sending ships to conquer Spain 500 years ago?
It's a difficult, racially-charged question, a mystery that puzzled historians for centuries.
Until 1997, when a brilliant researcher named Jared Diamond wrote his Pulitzer Prize-winning "Guns, Germs and Steel." It's a masterpiece of anthropological sleuthing and one of my all-time favorite books. I feel privileged to tell you a little of Diamond's findings, but also unworthy of the honor; I urge you to read this fascinating work for yourself.
The solution to the mystery starts with animals. Big domestic animals were a major factor in helping early human settlements in Eurasia progress toward civilizations. They provided land transport, milk products, meat, wool, leather, ploughing power, and military vehicles, to mention a few contributions. All are well known, but what Diamond focused on was their most unwelcome contribution: germs -- which ultimately turned out to be the Europeans' deadliest weapon.
The major killers of humanity throughout history -- smallpox, TB, plague, etc. -- are infectious diseases that evolved from animals. The humans who first domesticated animals were the first to become infected, but these humans evolved considerable resistance to the new diseases.
By a quirk of fate, almost all big animals which could be domesticated evolved in Eurasia. These included sheep, goats, cows (aurochs), pigs, and horses. Almost none existed in the Americas.
To be domesticatible, an animal must be reasonably docile, submissive to humans and willing to be herded, cheap to feed, and must breed well and grow rapidly in captivity. One or another of these requirements excluded each of America's large native animals: buffalo, antelope, bighorn sheep -- all but the llama. (To this day, no one has fully domesticated the American buffalo.)
So that's why, by 1500AD, Europeans carried the nastiest germs, with reasonably high immunity, and humans in isolated parts of the world did not.
Fate not only favored Eurasia with most of the domesticatible large animals, but also with an abundance of domesticatible grains and cereals. Unfortunately, the Western Hemisphere had very few. This good fortune enabled the earliest settlements in the Middle East to develop self-sustaining agriculture at least 5,000 years earlier than human societies in the Americas.
As explained in the prior page, the process of civilization tends to accelerate once the foundations are in place, with food production and storage allowing people to specialize, and specialization leading to invention, and invention enabling civilization to progress ever faster.
With civilization in Eurasia having a 5,000-year head start, the future Aztec and Inca civilizations were doomed. Their only possible hope might have been to somehow develop faster once they began, despite their paucity of raw materials. But here again, fate dealt the early Americans another cruel hand.
The final key to the mystery of European dominance, Jared Diamond recognized, was hiding in plain sight: the orientation of earth's two largest hemispheres. Eurasia stretches east-west; the Western Hemisphere stretches north-south. Follow along here, as Diamond's insights solve the rest of the mystery.
The germination and growth of plants are adapted to temperature, rainfall, and seasonal variation of day length. Crops generally travel well in the same latitudinal range, but almost always fail when planted very far to the north or south. As a result, cereals of Middle East origin proved immediately productive in Eurasia's many Mediterranean climate zones, from the Atlantic coast of Ireland to the Pacific coast of Japan. In contrast, the potatos and manioc of the Incas' predecessors never got to Mexico, and the corn and beans of Mesoamerica never got to South America.
The easy spread of crops across Eurasia not only accelerated the growth of civilizations on that continent, it stimulated contact between the many different Eurasian peoples. Transfer of crops and farming techniques contributed to trade networks, which as always, managed to survive frequent wars.
Competition between products and cross-fertilization of new ideas flourished across the entire 8,000-mile-wide temperate zone of Eurasia. And along with ideas, germs were transferred. Many people died, but immunity steadily evolved in the survivors.
Meanwhile, none of this was happening in the Americas. Even the useful llama never made it north through the Central American rain forests to help the proto-civilizations in Mesoamerica.
So that's the answer to the mystery. The feeling of superiority cherished by so many caucasions is baseless. We were conquerors not because of greater brainpower or being "more evolved," but by dumb luck. Fate blessed Eurasia's early civilizations with a combination of geography, environment, and raw materials which ultimately gave European civilization insurmountable advantages over other human societies.