Guns, Germs, and Steel: The Fates of Human Societies

Food production

• Only within the last 11,000 years did some people begin food production, which involves domesticating wild animals and plants, and eating the resulting livestock and crops.
• Consider food production and hunting-gathering as competing alternative strategies.
  • In some areas, the availability of wild foods declined and the availability of domesticable wild plants increased, leading to plant domestication.
  • Adoption of food production is an autocatalytic process: it catalyzes itself in a positive feedback cycle, going faster and faster once it has started.

How did certain wild plants turn into crops?

• Plant domestication is growing a plant and causing it to genetically change in ways that make it more useful to humans.
• For instance, there’s enough cyanide in a few dozen wild almonds to kill a person. But an occasional almond tree has a gene mutation that prevents it from creating that bitter taste.
  • Usually, that meant that the mutated tree would die without reproducing because animals would eat all the seeds.
• But curious or hungry children of farmers would notice them, and these would have been the only almonds that farmers would plant, causing the gene mutation to proliferate.
• In another example, wild wheat and barley seeds grow at the top of a stalk and then fall, dropping the seeds so they can germinate.
  • A gene mutation prevents the seeds from falling, and these would have been the ones waiting on the stalk to be harvested and replanted.
• So, farmers reversed the direction of natural selection for many plants: formerly successful genes became lethal, and lethal mutant genes successful.
  • These mark the first major human “improvements” in plants, at the beginning of agriculture in the Fertile Crescent (land in the Middle East, near the Mediterranean Sea).
• The next stage of crop development was fruit and nut trees, around 4,000 B.C., including olives, figs, dates, pomegranates, and grapes; then came trees like apples, pears, plums, and cherries.
• By Roman times, almost all of today’s leading crops were cultivated somewhere in the world.

Why did agriculture arise in some places but not others?

• Agriculture began in the Fertile Crescent likely because the crops there naturally met humanity’s basic needs re carbohydrates, protein, and fat–crops in other parts of the globe were not equally productive. 
• The Americas, in contrast, only had crops that had a modest potential for domestication, which led to a much later start to food production.

Population

• As a direct consequence of planned food production, farmers had to be near their fields and orchards.
• This contributed to fixed housing, a shortened birth interval because people could have as many children as they could feed (versus hunter-gatherers who generally spaced their children four years apart), leading to bigger human populations.

Domesticated animals and the Anna Karenina principle

• A domesticated animal is one selectively bred in captivity and modified from its wild ancestors, for use by humans who control the animal’s breeding and food supply.
• From Leo Tolstoy’s novel, Anna Karenina: “Happy families are all alike; every unhappy family is unhappy in its own way.”
  • This principle explains a feature of animal domestication that had heavy consequences for human history–why so many seemingly suitable big mammal species, such as zebras, have never been domesticated, and the successful domesticates were almost exclusively Eurasian.

There have only been 14 big species (100+ lbs) domesticated before the 20th century

• There’s the “Minor Nine,” which were important livestock but did not spread around the world–the Arabian camel, the Bactrian camel, llama/alpaca, donkey, reindeer, water buffalo, yak, Bali cattle, and gaur.
• The “Major Five” did spread around the world–cow, sheep, goat, pig, and horse.
• To be domesticated, a wild species must possess many different characteristics; lack of a required characteristic dooms the domestication effort (the Anna Karenina principle):
  • Diet – animals require a lot of food, and because of this fundamental inefficiency, no big mammalian carnivore has ever been domesticated.
  • Growth rate – animals that grow too slowly are not worth keeping (gorillas, elephants).
  • Captive breeding – many animals have elaborate breeding rituals that cannot be carried out in a cage (cheetahs).
  • Nasty disposition – many large animals are aggressive, nasty, and incredibly dangerous (bears, zebras).
  • Tendency to panic – nervous species are difficult to keep in captivity, as they either die of shock or batter themselves to death (gazelles)
  • Social structure – many mammals have a well-developed dominance hierarchy, which is ideal for domestication because humans just put themselves at the top.
    • Also, social animals are tolerant of each other, but solitary or highly territorial species cannot be herded and are not instinctively submissive.

Eurasia’s dominance

• Eurasia had the most candidate species of wild mammals to start with, and lost the fewest to extinction.
• And when Eurasia’s Major Five reached Africa, many African peoples adopted them where possible, demonstrating that lack of native mammal domestication outside of Eurasia lay with the availability of the wild animals, not with the people’s ability to domesticate them.
• Because livestock were critical–providing meat, milk, fertilizer, and plow-pulling while also yielding natural fibers for making clothing, blankets, nets, and rope–having livestock was enormously beneficial to Eurasia.

Germs

• The major killers of recent humanity are smallpox, flu, tuberculosis, malaria, plague, measles, and cholera–all infectious diseases that evolved from animals.
  • Infectious diseases that visit us in epidemics, rather than a steady trickle of cases, share several characteristics:
    • The spread quickly from an infected person to a nearby healthy person;
    • They’re “acute” illnesses (you either die or recover completely);
    • The survivors are generally immune to the disease afterwards;
    • These diseases tend to be restricted to humans.
• Why was the exchange of nasty germs between areas so unequal, especially between the Americas and Europe?
  • Agriculture launched the evolution of our crowd-infectious diseases.
    • First, people who domesticated animals were the first to fall victim to newly evolved animal germs, but over time they evolved substantial resistance to the new diseases.
      • When these partly immune people came into contact with others who had no prior exposure, the resulting epidemics resulted in nearly 99% of the previously unexposed population dying.
      • So, germs that were acquired from domestic animals played a decisive role in conquest–especially European conquests.
    • Second, farming communities had higher populations living closer together, leading to increased spread.
    • Third, farmers (unlike hunter-gatherers) did not shift camp, so they lived in their own sewage, which was teeming with germs.
• Not a single major killer reached Europe from the Americas (with the possible exception of syphilis, origin controversial).
  • One potential factor is that dense human populations began later in the Americans than in Eurasia, and of those dense areas in the Americas, they never became so connected by regular trade such that one place could become a massive breeding ground for germs.
  • Also, there were only five animals domesticated in the Americas, and of those, they were smaller in number and had limited contact with humans.
  • However, there were some devastating diseases that traveled from Asia, Africa, Indonesia, and New Guinea to Europe: malaria, cholera, and yellow fever.

Geographical axes

• The Americas span a much greater distance north-south than east-west, and Africa is similar. In contrast, Eurasia is much larger east-west.
• Axis orientations massively impacted critical factors, such as the rate of spread of crops and livestock.
  • For instance, the rate of spread of crops from the Fertile Crescent was so rapid because places east and west of each other, at roughly the same latitude, share the same day length and seasonal variations. They also share similar diseases, rainfall, and vegetation.
  • The germination, growth, and disease-resistance of plants are adapted to those climate features, since seasonal changes of day length, temperature, and are signals that stimulate seeds to germinate, grow, and develop.
  • Animals are also sensitive to latitude-related features of climate, which is partly why domesticated animals in the Fertile Crescent spread between the east and the west so rapidly–this ultimately aided in the rapid diffusion of Eurasian writing metallurgy, technology, and empires.

Writing

• Writing brought power–it allowed people to transmit knowledge with great accuracy, and in great quantity and detail. 
• Why did only some people develop writing and not others? For instance, why did writing spread to Ethiopia and Arabia from the Fertile Crescent, but not to the Andes from Mexico?
• Inventing a writing system from scratch must have been incomparably more difficult than borrowing and adapting one.
  • The two indisputably independent inventions of writing were the Sumerians of Mesopotamia around 3,000 B.C., and Mexican Indians before 600 B.C.
    • (Though Egyptian writing in 3,000 B.C. and Chinese writing in 1,300 B.C. may also have arisen independently).
• Writing spread via two contrasting methods:
  • Blueprint copying: when someone copied or modified an available writing system;
  • Idea diffusion: when someone received the basic idea of a writing system, and then reinvented the details.
• In the beginning, very few people could write–for instance, in ancient Sumer, writing was used by professional scribes to record the numbers of sheep owed in taxes. 

Technology

• Why did technology evolve at such different rates on different continents?
• Much of new technology is not invented locally but instead borrowed from other societies. When a widely useful invention does crop up in one society, it then tends to spread in either of two ways:
  • Other societies see it and adopt it.
  • Societies lacking the invention are disadvantaged, and become overwhelmed and replaced if the disadvantage is sufficiently great (for instance, the spread of muskets among New Zealand’s Maori tribes, and the combative advantage this gave them).
• Because technology begets more technology, the importance of an invention’s diffusion potentially exceeds the importance of the original invention.
• The time of onset of food production, barriers to diffusion, and human population size led to differences in the development of technology.
  • Eurasia is the world’s largest landmass and lacks the severe ecological barriers of the Americas and Africa, so ideas and inventions spread more quickly.
  • This translated into a huge lead by 1492.

From egalitarianism to kleptocracy

• Early humans lived in bands, which is the political, economic, and social organization inherited from millions of years of evolutionary history.
• Hunter-gatherers were fairly egalitarian and had a small-scale political organization, because all able-bodied people were required to acquire food.
• But early farmers learned how to store surplus food, which became essential for feeding non-food-producers, such as kings and bureaucrats.
  • This way, a political elite could readily form, gain control of food produced by others, assert the right of taxation, escape the need to feed themselves, and fully engage in political activities.
    • Stored food also feeds priests, who provide religious justification for wars, metalworkers who develop swords and other artillery, and scribes, who preserve far more information than can be memorized.
  • These complex political units are much better equipped to mount wars.
  • Only a few areas of the world developed food production independently. If hunter-gatherers in neighboring areas learned food production, they had an advantage in invading hunter-gatherers in other areas.

• The next stage beyond the band is a tribe–it usually had fixed settlements and was larger.
  • Tribes had an informal, egalitarian system of government, where information and decision-making were communal, and the head of the tribe usually did not have independent decision-making authority.
• After that is a chiefdom.
  • At this stage, the form of government tends to morph, because at around a population of several hundred members, conflict resolution becomes increasingly difficult, and because chiefdoms ranged from several thousand to several tens of thousands of people, the rates of internal conflict grew significantly.
  • Chiefdoms introduced a fundamental dilemma that nearly all centrally-governed, non-egalitarian societies face: at best, theyprovide expensive services that are impossible to acquire on an individual basis, and at worst, they are kleptocracies, transferring net wealth from commoners to the upper class.
    • The difference between a robber baron and a public benefactor is just one of degree: how much tribute is extracted from producers and retained by the elite, and how much do the commoners like the public uses to which the redistributed tribute is put?
• In these large societies, why do the commoners tolerate the transfer of the fruits of their hard labor to kleptocrats? Kleptocrats have resorted to a mixture of four solutions:
  • Disarm the populace and arm the elite;
  • Make the masses happy by redistributing much of the tribute, in popular ways;
  • Use the monopoly of force to promote happiness, via maintaining public order and curbing violence;
  • Construct an ideology or religion justifying kleptocracy.

Hemispheres colliding

• Why did Europeans reach and conquer the lands of Native Americans, instead of vice versa? As noted previously the most important differences between the two hemispheres included differences in germs, technology, political organization, and writing.
• Technology
  • Metals (copper, bronze, and iron) were used for tools in all complex Eurasian societies as of 1492. In contrast, stone and wood and bone were still the principal materials for tools in all Native American societies.
  • Second, military technology was more advanced in Eurasia, including steel swords, lances, small firearms and artillery, and horses.
  • Third, Eurasian societies had a huge advantage in machine operation, including the use of strong animals for much of the manual labor.
  • Last, Eurasians had sea transport, such as large sailing ships, which were superior to the rafts used for trade in the Americas.
• Food
  • American wild plants also contributed to decreased food production in the Americas–less than a dozen crops were domesticated, and none were large-seeded grains, fiber crops, or cultivated fruit or nut trees.
  • Eurasia also had easier diffusion of animals, plants, ideas, technology, as a result of several sets of geographic and ecological factors (including the axes).
• The end result has been the elimination of populous Native American societies from most temperate areas suitable for European food production and physiology.
  • In North America, those that survived now live mostly on reservations. Even where Native Americans do survive, there has been extensive replacement of their cultures and languages.

Why did the Fertile Crescent and China lose their enormous leads to Europe?

• In the Fertile Crescent, these societies had the misfortune to arise in an ecologically fragile environment, and as a result, power shifted westward.
• China losing its lead is initially surprising.
  • China enjoyed many advantages: a rise of food production nearly as early as in the Fertile Crescent; and rich ecological diversity.
  • It also had a long list of major technological firsts, and led the world in political power, navigation, and control of the seas.
  • But the end of China’s fleets gives a clue. Seven such fleets sailed between 1405 and 1433. But they were then suspended due to a political power struggle.
    • When a new faction gained the upper hand, it stopped sending the fleets and eventually dismantled the shipyards, and forbade oceangoing shipping.
    • So, because all of China was politically unified, a single decision was able to stop all fleets from exploration.
• In contrast, because Europe was fragmented, Columbus succeeded on his fifth try in persuading one of Europe’s hundreds of princes to sponsor him–whereas when China unified in 221 B.C., no other independent state ever had a chance of persisting for long.
  • The Chinese court occasionally halted other activities: it abandoned development of an elaborate water-driven spinning machine, stepped back from the verge of an industrial revolution in the 14th century, and retreated from mechanical devices and technology in general after the late 15th century.
  • Those harmful effects of unity have flared up again in modern China, notably during the Cultural Revolution in the 1960s and 70s, when a decision by a few leaders closed all school systems for five years.
  • Europe’s geographic balkanization resulted in dozens or hundreds of independent, competing statelets and centers of innovation. If one state didn’t pursue some particular innovation, another did, forcing neighboring states to do likewise or else be conquered or left economically behind.

• A succinct summary of the last 13,000 years that examines our evolutionary trail
• The Moriori v. the Maori – a brief, small-scale natural experiment that tests how environments affect human societies
• A gripping retelling of the dramatic and critical encounter between Inca emperor Atahuallpa and the Spanish conquistador Francisco Pizarro in Cajamarca, Peru in 1532, and how the factors that resulted in Pizarro’s seizing of Atahuallpa were essentially the same ones that determined the outcome of many similar collisions between colonizers and native peoples elsewhere in the modern world
• Where, when, and how food production developed in different parts of the globe
• A close examination of Africa’s food production, domesticable animals, and how that impacted its historical trajectory
• How Australia provides a crucial test of theories about intercontinental differences in society, since it is the driest, smallest, flattest, most infertile, climatically most unpredictable, and biologically most impoverished continent
• How China became Chinese, and its seminal role in East Asian civilization
• The transformation of Polynesia, and how the outcome of the Austronesian expansion in the New Guinea region compared to that of Indonesia and the Philippines