Guns, Germs and Steel - Jared Diamond

Preface
Why did history unfold differently on different continents?

Prologue - Yali's Question
Why did wealth and power become distributed as they are now, rather than in some other way ? Or why did human development proceed at such different rates on different continents ?

Summary of book in one sentence - 'History followed different courses for different people because of different among peoples' environments, nor because of biological differences among people themselves.'

Part 1: From Eden to Cajamarca
Chapter 1: Upto the starting line
Starting point is 13,000 B.C. beginning of village, start of Recent Era, plant and animal domestication etc.
Human origin in Africa:
African Apes





Cro Magnon Man: Cro Mangons lived simultaneously along with Neanderthals, but somehow used their superior skills of technology and their language skills or brains to infect, kill, or displace the Neanderthals, leaving behind little or no evidence of hybridisation between Neanderthals and Cro Magnons. Cro Magnons had sense of art and their painting in the cave of France are still appreciated.



The Great Leap Forward coincides with extinction of many species from across continents, some 30k-40k years ago. There are counter arguments that the species might have become extinct because of climate change such as floods or droughts. But, as per the author if the species survived innumerable such climate changes over thousands of years, but became extinct as soon as humans arrived, points towards only one direction. Either the species were exterminated directly (killed for food etc.) or indirectly (fire or habitat modification caused by humans). But the fact is that the extinction coincided with the arrival of humans at places such as Australia / New Guinea (Island above Australia).

What significance, if any, do the continents' differing dates of settlement have for subsequent history?
Archaeologists have arguments for each continent, and their head-start over other regions:
Africa - Earliest settlement, highest human genetic diversity.
Americas - greater area as compared to Africa and much greater environment diversity
Eurasia - Eurasia is the second oldest settlement, but before that African settlement was very primitive, hence any advantage of Africa is negated.
Australia/New Guinea - Newest settlement but earliest watercraft. All the advancement passed through them to Eurasia and Africa.

If a time traveller in 11,000 BC could not have predicted on which continent human societies would develop most quickly, but could have made strong case for any of the continent. But in-hindsight, of course, we know it was Eurasia. The quest for real reasons will be in the following chapters.

Chapter 2 - A Natural Experiment of History
On the Çhatham Island, 500 miles east of New Zealand, Moriori people were killed by well equipped Maori people armed with guns, clubs and axes. The Moriori were small, isolated population of hunter gatherers, equipped with simplest of technology and weapons, entirely inexperienced at war. On the other hand Maori invaders came from a dense population of farmers chronically engaged in brutal war, equipped with advanced technology and weapons.
Both were Polynesian people, Maori stayed in New Zealand, but a small population out of them colonised on Chatham island and became Moriori. Essentially the ultimate ancestors shared the same culture, language, technology and set of domesticated plants and animals.
Hence this history constitutes a brief, small scale natural experiment that tests how environments affect human societies.

Moriori	Maori
Traditional Maori crops could not grow in the Chathams cold climate, and the colonists had no alternative except to revert to being hunter gatherers	Polynesian agriculture. With production of pigs, dogs and chicken.
No crop surplus	Surplus hence can grow and store, and fed other professions
Their preys seals and shellfish, that could be captured by hands and required no elaborate technology.	They needed and developed varied tools for growing crops, fighting and making art. They organised work force to do there activities - irrigation, ponds for fish
With no other accessible island to colonise, they learnt to live together renouncing war.
Without strong leadership	Strong hierarchy

Contributing to these differences were at least 6 sets of environmental variables - Island climate, geological type, marine resources, area, terrain fragmentation, and isolation.
Climate - Some islands tropical suitable for agriculture, some cold not so suitable.
Island geological types -
Marine resources - In some places fish and other animals available, some less productive.
Area - Flat, easy for communication to hilly terrain difficult to travel.
Isolation -

How the variation influenced the societies ?
Polynesian subsistence depended on varying mixes of fishing, gathering wild plants and marine shellfish etc. As soon as islands became colonised, most easily hunted animals were exterminated, hence they were depended on their own food production.
3 domesticated animals, but not all reached other islands as either they might have died during the voyage or the live stock would have exhausted.

Polynesia furnishes us with a convincing example of environmentally related diversification of human societies in operation.

Chapter 3 - Collision at Cajamarca
The biggest population shift of modern times has been the colonisation of the New World by Europeans. How and Why ?
Ex - First encounter between the Inca emperor Atahuallpa (absolute monarch of the largest and most advanced state of New World) and Spanish conquistador Francisco Pizarro (represented the Holy Roman Emperor Charles V, monarch of the most powerful state in Europe) at the Peruvian highland town of Cajamarca on Nov 16, 1532. Pizarro, leading a ragtag group of 168 Spanish soldiers, in unfamiliar terrain, ignorant of local inhabitants, beyond any enforcement, beat Atahuallpa with 80,000 soldiers, within few minutes after the two leaders set their eyes on each other. Pizarro captured Atahuallpa and asked for ransom of quite a large sum of gold. After getting the ransom, he killed the emperor. The factors that resulted in such result were essentially the same that detrmined the outcome of many similar collisions between colonizers and native people elsewhere in the modern world.
Why did Pizarro capture Atahuallpa? Pizarro's military advantages lay in Spaniards steel swords and other weapons, steel armour, guns and horses. Atahuallpa troops without any animal to ride into battle, could oppose with only stone, bronze, or wooden clubs, hand axes and slingshots. Pizarro slaughtered thinly armoured Indians. The shock of a horse's charge, its manoeuvrability, the speed of attack that it permitted and raised platform that it provided left foot soldiers helpless.
The transformation of warfare by horse began with their domestication around 4000 BC.

How did Atahuallpa come to be at Cajamarca ? Atahuallpa had won major civil battle for power capture after the main emperor dies of epidemic, caused when the Spanish settlers came in contact with the Indians. If not for epidemic, Spaniards would have faced a united empire. Thus one factor for success of Europeans were transmission of diseases from immune people to less immune people. There are multiple examples of such cases. Also disease such as yellow fever, malaria found in Africa, Southeast Asia and New Guinea were most important obstacle to European colonisation of those tropical areas.

How did Pizarro come to be at Cajamarca ? He came to Cajamarca by means of European maritime technology, along with centralised political organisation that enabled finance, build staff and equip the ships. Inca also had centralised political organisation but that worked against them once emperor was captured.
A related factor bringing Spaniards to Peru was writing. Letters and pamphlets with motivation and necessary sailing instructions.

Why did Atahuallpa walk into the trap ? Atahuallpa had very little information about the Spaniards. Literacy (writing) made the Spaniards heirs to huge body of knowledge about human behaviour and history. Atahuallpa had no conception of any other invaders from overseas, nor heard (or read) of any similar threats to anyone else previously in history.

Thus factors - military technology based on guns, steel weapons, and horses; infectious diseases endemic in Eurasia, maritime technology, central political organisation and writing.

Part 2: The Rise and Spread of Food Production:
Chapter 4: Farmer power
How did farmers win out over the most famous warriors ?
Only in the last 11,000 years, some people have started some form of food production, i.e. domesticating wild animals and plants. Food production was indirectly a prerequisite for the development of guns, germs and steel. Connection between food production and loss of Atahuallpa:
First: availability of more consumable calories means more people. Once acre of land can feed many people more than hunter gatherers. The strength of brute numbers was the first of many military advantages that food producing tribes gained over hunter gatherers. Hunter-gatherer societies moved frequently in search of wild foods, but farmers must remain their fields and orchids. Thus farmers had denser human population and shortened birth cycle as women do not need to move frequently, but could give child birth on shorter frequency with available resources for feed. Also storage along with production. Once the storage of food starts, a political elite can take control of the food produced b others, asserts the right of taxation, and engage in full time political activity, where as in hunter gatherers all able bodied men have to hunt for food. Hence moderate size agriculture societies are often organised in Chiefdoms and kingdoms are confined to large agriculture society. Surplus food can be used to feed soldiers, to priest who provides religious justification for wars of conquest, artisans for development of swords, guns and other technology.
Diverse epidemic diseases of human population evolved in areas with many wild plants and animal species suitable for domestication, partly bec resulting crops and livestock helped fed dense societies in which epidemic could maintain themselves, and partly be the disease evolved from germs of the domestic animal themselves. Other importance in wars of conquest were the germs that evolved ib human societies like smallpox, measles, and flu, derived from mutation of very similar ancestral germs that had infected animals. The humans who domesticated were the first to fall ill to these diseases, but then they developed substantial immunity.
Big domesticated mammals further revolutionized human society by becoming our main means of land transport until the development of railroads. The most direct contribution of plant and animal domestication to the war of conquest was from Eurasia's horses, who played major military role.

Hence availability of domestic plants and animals, ultimately explains why empires, literacy and steel development developed earliest in Eurasia and later, or not at all, on other continents.

Chapter 5: History's Have and Have-Nots
In short, only a few areas of the world developed food production independently, and they did so at widely differing times. From those nuclear areas, hunter-gatherers of some neighboring areas learned food production, and peoples of other neighboring areas were replaced by invading food producers from the nuclear areas - again at widely differing times. Finally, peoples of some areas ecologically suitable for food production neither evolved nor acquired agriculture in prehistoric times at all; they persisted as hunter-gatherers until the modern world finally swept upon them. The people of areas with a head start on food production thereby gained a head start on food production thereby gained a head start on the path leading towards guns, germs and steel.

Chapter 6: To Farm of Not to Farm
Formerly all people on Earth were hunter-gatherers. Why did any of them adopt food production at all ? Most peasant farmers and herders, who constitute the great majority of the world's actual food producers, arent necessarily better of than hunter-gatherers. Time budget studies show that they may spend more rather than fewer hours per day at work than hunter-gatherers do. Also less well nourished than hunter-gatherers. Then why did this choise was made?
Hunter-gatherers in contact with farmers did eventually become farmers, but only after what may seem to us like an inordinate long delay. Food producers did not make a conscious choice because there was no precedence. Hence food production evolved as a by-product of decisions made without awareness of their consequences.
In early stages of food production, people simultaneously collected wild foods and raised cultivated ones, and diverse types of collecting activities diminished in importance at different times as reliance on crops increased.
Hunter-gatherers saw the results of the food production of the neighboring hunter-gatherers. In some cases they adopted the entire package of food production or partly. Food production decision was not made in a vacuum, but emerged as as alternative strategy compared to hunter-gatherers. What factors tipped the balance in food production ? 5 factors
1. Decline in availability of wild foods, as resources on which they depended became extinct.
2. Increased availability of domesticable wild plants.
3.Development of technologies for collecting, processing, and storing wild foods.
4. Rise in population and rise of food production. Chicken and egg story. The food production is auto catalytic process - one that catalyzes itself in a positive feedback cycle.
5. Much denser population of food-producers displaced/killed hunter-gatherers by their sheer numbers along with technology, germs and professional soldiers.

Chapter 7: How to make an Almond
Few dozen wild Almonds contain enough cyanide to kill a person. The forest is full of such plants deemed inedible. Yet all crops arose from wild plant species. How did certain wild plants get turned into crops ? What caveman ever got the idea of 'domesticating' a pland, and how was it accomplished?
Plant domestication may be defined as growing a plant and thereby, consciously or unconsciously, causing it to change genetically from its wild ancestor in ways making it more useful to human consumers. Today there any many technologies and genetic mutation for selecting a useful crop. But ancient people did not have such knowledge, so what made some plants so much easier or more inviting to domesticate than others ? Why did some trees got domesticated but some not ?
Plant seeds can resist digestion by your gut and germinate out of feces. What unconscious criteria influence us to eat a particular fruit ?
1. Size
2. Bitterness - Plants whose fruits are tasty has to have bitter tasting seed so that animals don't eat it but rather disperse it. Almonds provides a striking example of bitter seeds and their change under domestication. Most wild almond seeds contain an intensely bitter chemical called amygdalin, which breaks down to yield cyanide. Then how did domestication happen ? The explanation is that occassional individual almond trees have a mutation in a single gene that prevents them from synthesizing the bitter-tasting amygdalin. Such trees die out in the wild without leaving any progeny, because birds discover and eat all their seeds. But curious and hungry children of early farmers, would have found those nonbitter almond seeds and would have planted, at first unintentionally in their garbage heaps (thrown out) and later intentionally in orchids.
3. Fleshy/seedless fruit/oily seeds/long fibers - one of the oldest crop flax, furnished linen.
Hence by selecting wild plants on the above criteria ancient people unconsciously dispersed the plants and set the, on the road to domestication. Other example - self popping peas for germination, but people preferred non-popping ones. Thus human farmers reversed the direction of natural selection by 180 degrees; the formerly successful gene suddenly became lethal, and the lethal mutant became successful. Over 10k years ago, the unconscious selection for nonshattering what and barley stalks was apparently the first major human 'improvement' in any plant. That change marked the beginning of agriculture in the Fertile Crescent. There were other factors also, one was plant reproduction. Vast majority of plants do not reproduce themselves. The solution involved that numerous plant mutations affected the reproductive system itself. Some mutants developed fruit without even having to be pollinated, resulting in seedless banana, grapes, oranges and pineapple. Some mutants were able to fertilize themselves. Thus farmers selected from among individual plants on the basis not onlyu of perceptible quality such as size and taste but also of invisible features like seed dispersal mechanism, germination inhibition and reproductive biology.

(10k BC years ago) Many advantages of early crops such as wheat and barley around 10k years ago - already edible, high yields, easily grown merely by being sown or planted, could be harvested in a few months of sowing, readily stored, self pollinating and able to pass the genes intact rather than hybridization which would make the plant less useful to humans.
(4k BC years ago) first fruit and nut trees, domestication. They comprised olives, figs, dates, pomegranates, and grapes. They had the dis-advantage of not starting to yield food until at least 3 years after planting and not reaching to full production until after much as a decade.
(3rd stage) cultivate harder fruit trees such as apples, pears, plums and cherries. They possesses the problems that they were opposite of self-pollinating. They had to be cross-pollinated with another plant belonging to a genetically different variety of their species. Hence early farmers have to either find a self-pollinating mutant or consciously plant genetically different varieties or else male and female individual near by in the same orchid. All these reasons delayed the domestication of these trees. Darwin states that account of how our domesticated plants and animals arose through artificial selection by humans ans serves as our most understandable model of the origin of species by natural selection.

Chapter 8: Apples or Indians
Why did agriculture never arise independently in some fertile and highly suitable areas such as California, Europe, temperate Australia, and subequatorial Africa ? Why among the areas where agriculture did arise independently, did it develop much earlier in some than in others?
Two contrasting explanations suggest themselves: problem with the local people or problem with the locally available wild plants. Plants have much higher species as compared to mammals - 200,000. If there are so many of the wild plants then any area with a sufficiently benign climate must have had more than enough species to provide plenty of candidates for crop development, but this was not the case. Of the 200,000 wild plant species, only a few thousand are eaten by humans, and just a few hundreds of these are more or less domesticated. Even out of these several hundred of crops, most provide minor supplements to our diet and would not have themselves been sufficed to support the rise of civilisation. A mere dozen of species account for over 80% of the modern world's annual tonnage of crops. Ex - cereals, wheat, corn, rice, barley and sorghum; the pulse soybean; the roots or tubers potato, manioc, and sweet potato; sugarcane and sugar beat; fruit banana. Cereal crops alone now account for more than half of the calories consumed by the worlds population. Our failure to domesticate even a single new major food plant in modern times suggests that ancient people must have virtually explored all useful wild plants and domesticated.
Why the plants were domesticated in one area but not in other. The other areas outside Fertile Crescent started using it only when they were already domesticated in other ares and brought from outside - there are many examples. But there is fatal flaw in the reasoning: plant domestication is not a matter of  hunter-gatherers domesticating a single plant and otherwise carrying on unchanged with their nomadic lifestyle. Hunter gatherers will not throw away their traditional life style, settle in villages until many others domesticated wild plants and animals were available to make sedentary food producing existence competitive with hunting-gathering existence. In order to answer these questions we will compare 3 regions:
Fertile Crescent (todays Jordan, Syria and Iraq) - The area appears to have been the earliest site for a whole strings of developments, including sites, writing, empires and civilisation. Food production was first major innovation. hence any attempt to understand the origins of modern world must answer the question why the FCs domesticated crops and animals gave it such a potent head start.
One Advantage: it lies within a zone of so-called Mediterrannean climate, characterised by mild, wet winters and long, hot, dry summers. Many FC plants esp species of cereals and pulses, have adapted in a way that renders useful to humans. Within their 1 year of life, annual plants inevitable remain small herbs. Many of them instead put much of their energy into producing big seeds, which remains dormant during dry season and are then ready to sprout when the rain comes. Annual plants therefore waste little energy into making inedible wood or fibrous stems, like trees or bushes.
Sec Advantage: wild ancestors of many FC crops were already abundant and highly productive, occurring in large strands whose value must have been obvious to hunter gatherers. Some HG people must have settled down in permanent villages even before they Bagan to cultivate plants. Few additional changes had to be made in their cultivation. Principle changes - breakdown of the natural system of seed dispersal and of germination inhibition - evolved automatically and quickly as humans began to cultivate the seeds in fields.
3rd Adv: includes high percentage of hermaphrodite "sellers" - that is plant that that usually pollinate themselves but that are occasionally cross pollinated, convenient to humans. They also occasionally cross pollinated (same species and related species) thereby generating new varieties among which to select. Of the first 8 significant crops to have domesticated in FC all were selfers - with additional advantage of high protein content 8-14 %. In contrast, the most important cereal crops of easters Asia and of New World - rice and corn esp. had allowed protein content that posed significant nutritional problems.
There are also zones of similar Mediterranean climates in four other parts of the world: California, Chile, SW Australia and South Africa. Yet these other Mediterranean zones not only failed to rival the FC, they never gave rise to indigenous agriculture at all. What advantage did that particular Mediterranean zone of Western Eurasia enjoy ?
5 advantages: 1) Western Eurasia has world's largest zone of Mediterranean climate, as a result high diversity of wild plants and animal species. 2) Experiences greatest climatic variation from season to season and year to year - favoured the flora, of an esp. high % of annual plants. This fact goes long way towards explaining the course of human history. 3) offers wide range of altitudes and topographies within a short distance. It ranges from the lowest point on earth -Dead Sea to mountains of 18k feet, near Teheran, ensures a corresponding variety of environments, hence high diversity of wild plants serving as potential ancestors of crops. Those mountains are in proximity to gentle lowlands with rivers flood plains, and deserts suitable for irrigation agriculture. The range of altitude meant staggered harvest season: plants at higher elevation produced seeds somewhat later than plants at lower elevation. As a result HG could move up a mountain side harvesting grain seeds as they matured, instead of being overwhelmed by a concentrated harvest season. 4) Its wealth of big wild mammals. There were few no wild mammal species suitable for domestication in other zones - California, Chile, and others. 4 big species -goat, sheep, pig, and cow were domesticated very early in FC.
Agriculture was launched in the FC by the early domestication of 8 crops, termed 'founder crops' - cereals, emmer wheat, einkorn, wheat, barley, pulses lentil, pea, chickpea and bitter vetch and finer crop flax. Of these only 2 flax and barley, found in wild outside FC. Hence agriculture can start in FC without waiting for crops to arrive from outside. Thanks to these, FC people could quickly assemble a potent and balanced biological package for intensive food production - there cereals as carbohydrate source; four pulses/wheat as 20-25% protein and animals and 4 domesticated animals as main protein source, clothes and transport, flax as source of fibre and oil.
5) it may have faced less competition from the HG lifestyle than that in some other areas, including wester Mediterranean. SW Asia has few large rivers and only a short coastline, providing meager aquatic resources. Thus the food growing quickly became superior to HG.
But what about people living their, do their qualities also contribute to the FC agriculture ? The study of many such HG societies have shown that HG have complete detailed knowledge about the species of their area, hence they would hardly have failed to cultivate any useful wild plant species that was completely suitable for domestication.
Modern New Guinea hunters suffer from crippling disadvantage of dearth of wild animals: there is no native land animal larger than 100 point flightless bird and a 50 pound kangaroo, NG suffered from several limitations: 1) No cereal crops were domesticated here, as not one of the world's 56 largest seeded wild grasses is native there. 2) no domesticable large mammals are available. Animals arrived from outside. hence they suffered from sever protein deficiency. Lowlanders obtain their protein from fish, but highlanders does not have such. Children in NH have swollen bellies characteristic of high-bulk but protein deficient diet. Also the reason why cannibalism was wide spread in traditional NG highland societies. 3) NG crops were limiting in calories as well as in protein, because they do not grow well thigh elevations where may NG live today. The result of sweet potato arrival from outside resulted in population explosion. Thus the limits on indigenous food production in NG had nothing to do with NG people, and everything to do with the NG biota and environment. All the regions more or less developed indigenous ways to domesticate crops, but the timeline varies. Some regions developed pretty early ex- Fertile Crescent some later that what gave them the advantage not the people living in the areas.

Chapter 9: Zebras, unhappy marriages, and the Anna Karenina Principle
Domesticable animals are all alike; every undomesticable animal is undomesticable in its own way. Domesticable animals were crucial to the human societies as they provided meat, milk, products, fertilizer, land transport, leather, military assault vehicles, wools as well as germs that killed previously unexposed people. Out of big animals (weighing over more than 100 pounds), then only 14 such species were domesticated before 20th century. Of these the Minor Nine (arabian camel, bactrian camel, llama and alpaca, donkey, reindeer, water buffalo and yak) became important livestock for people in limited areas. Only 5 major species became widespread and important across world (cow, sheep, goat, pig and horse). Elephants have been tamed but never domesticated. Domestic animals is defined as an animal selectively bred in captivity and thereby modified from its wild ancestors, for use by humans who control the animals breeding and food supply i.e. wild animals being transformed into something more useful to humans. Truly domesticated animals differ in various ways from their wild ancestors. These differences differ from 2 processes: human selection of those individual animals more useful to humans and automatic evolutionary responses of animals to the altered forces of natural selection operating in human environment. Many species changed in size  - cows, pigs, and sheeps became smaller, while guinea pigs larger. Several species have smaller brains and less developed sense, because they no longer needed them. Wolves were the wild ancestors of dogs.
The wild ancestors of the ancient were unevenly spread over the globe - south america had only one ancestor, north america and sub-saharan had none at all - important reason why Eurasians rather than other people, were the one to end up with guns, germs and steel. But how can we explain the concentration ? - Eurasia had largest number of wild animals species. Any terrestial herbivorous or omnivorous species weighing on an average over 100 pounds is defined as candidate for domestication, then Eurasia has most candidates (72/85). Thats because Eurasia is worlds largest landmass, and its also very diverse ecologically, with habitats ranging from extensive tropical rain forest, deserts, and marshes, to equally extensive tundras. Eurasia was the continent with most candidates species of wild animals to start out with and lost the fewest candidates to extinction in the last 40k years. Why were large number of species of African and American mammals were never domesticated, despite their having Eurasian close relative that were domesticated. Eurasias horse domesticated but not Africas Zebras, E pigs, but not Am peccaries or Af wild pigs.
Did all other people share some cultural obstacle to domesticate wild animals ? No
First Evidence: Whenever people lacking native wild animal species got the opportunity they domesticated E wild animals.
Second Evidence: All species kept pets, but only few emerged as domesticated
Third Evidence: Genetic evidence suggests that all species of different types belong to the same species. Thus same few suitable wild species attracted the attention of many different human societies. Thus failure to domesticate large residues of wild animals arose from shortcomings of the species rather than the ancient humans.

Of the worlds 148 big species only 14 were domesticated, why ?
Diet: It takes 10k pounds of corn to grow a 1k p cow, and 1k p of carnivore then 10k p of herbivore.
As a result no mammalian carnivore has ever been domesticated for food. Also not those herbi with finicky in plant preference.
Growth Rate: To be worth keeping, animals must grow quickly - that eliminated many animals.
Problems of Captive Breeding: Some potential animals did not like having sex under watchful eyes.
Nasty Disposition: Tendencies to kill humans have disqualified many.
Tendency to Panic: Species with slower, less nervous response, seek protection in heard, stand their ground when attacked are easier to keep in captivity rather than nervous species.
Social structure: Almost all species of wild animals prove to be ones whose ild ancestors share three social characteristics - they live in heard, they maintain a well developed dominance hierarchy among heard members and the herds occupy overlapping home ranges rather than mutually exclusive territories.  That social structure is ideal for domestication, because humans in effect take over the dominancy hierarchy.
Thus Eurasians people happened to inherit manu more species of domesticable large wild mammalians herbivores than did peoples of the other continents. This fact stemmed from 3 basis facts: (1) Eurasia benefitting from its large area and ecological diversity, started out with most candidates (2) Australia and Americas and not Eurasia and Africa lost most of their candidates in massive wave of late-Pleistcene extinctions- possibly because former continents had the misfortune to be first exposed to humans suddenly and late in our evolutionary history, when our hunting skills were already highly developed. (3) highest % of surviving candidates got domesticated in Eurasia.

Chapter 10: Spacious Skies and Tilted Axes
America spread greater distance north-south than east-west; in contrast major axis of of Eurasia is east-west. What effect does it have on human history ?
Localities distributed east and west of each other of the same latitude share exactly the same day length and its seasonal variations. To a lesser degree, they also tend to share the same diseases, regimes of temperature and rainfall. The faster spread of Eurasian agriculture, compared with that of Native American and sub-Saharan African agriculture, played a role in the more rapid diffusion of Eurasian writing, metallurgy, technology and empires.

Part 3:
FROM FOODS TO GUNS, GERMS AND STEEL
Chapter 11
Lethal gift of Livestock

The major killers of humanity throughout history - smallpox, flu, TB, malaria, plague, measles, and cholera - are infectious diseases that evolved from diseases of animals.
The winner of past wars were not always enemies with best weapons and generals but were often those bearing the nastiest of germs to transmit to the enemies.
Disease from microbes point of view - What evolutionary benefit does microbe derive from making us sick and why should they evolve so as to kill us (killing its host) ? The germs that spreads better leaves more babies and ends up favored by natural selection. From a germs point of view symptoms of disease such as - genital sores, diarrhea and coughing - are clever evolutionary strategies to broadcast the germs. Thats why it's in germs best interest to make us sick. Why killing - thats just unintended by product of host symptoms promoting efficient transmission of microbe.
Fever ? coz some microbes are more sensitive to heat than our own bodies are.
Our slowest defence response is through natural selection, which changes our gene frequencies from generation to generation. Some people prove to be genetically more resistant than are others.
Microbes evolved to feed on the nutrients within our own bodies and they dont have wings to let them reach a new victim's body once the original victim is dead or resistant. Hence germs have developed new tricks to spread and many of these spreads are what we experience as 'symptoms of disease'. We and our pathogens are now locked in an escalating evolutionary contest.
To survive germs need sufficient and densely packed human population - Hence diseases like measles and similar diseases are also known as crowd diseases. Crowd diseases buildup began with the rise of agriculture starting about 10k years ago and then accelerated with the rise of cities. Because agriculture sustains much human population densities than does the hunter gatherer lifestyle. Farmers are sedentary and live amid there own sewage, spread their own faeces and urine as fertiliser in farms, thus making it easier to spread.
Many virus (measles, TB, smallpox, flu etc.) transferred from cattle to humans and then evolved by changing its properties to adapt to us. Microbes get winnowed by natural selection and only a few of them succeed in establishing themselves as human diseases. Four stages in the evolution of a specialized human disease from an animal precursor - (1) There are few diseases which we directly pick from our pets - all these microbes are in early stages of their evolution into specialized human pathogens. (2) Animal pathogens gets evolved to the point where it can transfer from human to human causing epidemic. However, the epidemic dies out for any of several reasons - cured by medicines, and immunity. (3) Pathogens developed in humans, that have still not died out, and that may or may not become major killers of humanity. (4) This stage of evolution is represented by major, long established epidemic diseases confined to humans.
North American Indians vs Europeans - The main killers of Indians were old world germs to which Indians were never exposed and had no immunity nor genetic resistance - smallpox, measles, influenza and typhus competed to be the top killers, malaria, plague, TB and yellow fever came close behind.
Why did awful germs waited for Europeans? - Rise of dense human population began somewhere later in new world than in new world and three major densely populated American centre never became connected by regular fast trade into huge breeding ground for microbes, in the way that Europe, North Africa, India and China became linked to Roman times. But this does not explain the failure of lethal crowd epidemics. Eurasian crowd diseases evolved out of diseases of herd animals that became domesticated, whereas many such animals existed in Eurasia only 5 animals of any sort became domesticated in Americas and else where. The few domesticates that remained still were not likely sources of crows diseases compared with cows and pigs - such as Ilamas (kept in smaller herds than sheeps, goats and pigs) (people dont drink their milk) (not kept indoors in close association with people)
Cumulative mortalities of these previously unexposed peoples from Eurasian germs ranged from 50% to100%

Chapter 12
Blueprints and Borrowed letters
Knowledge brings power. Hence writing brings power to modern societies, by making it possible to transmit knowledge with far greater accuracy and in far greater quantity and detail from more distant lands and more remote times.
With the possible exception of Egyptians, Chinese and Easter Island, all other writing system devised anywhere in world, at any time, appear to have been descendants of systems modified form or at-least inspired by Sumerians or early Mesoamerican writing. One reason - great difficulty of inventing it.
The writing appeared late in human evolution. Early writing served the needs of those political institutions (record keeping, propoganda etc.) and the users were full time bureaucrats nourished by stored food surplus, grown by food producing peasants. Writing were never adopted by hunter gatherers because they lacked both the institutional uses and social and agriculture mechanism for generating food surplus required to feed scribes.
Thus food production and thousands of years of societal evolution following its adoption were as essential for the evolution of writing as for the evolution of microbes. Writing arose independently in the Fertile Crescent, Mexico and probable China precisely because those were the first areas where food production emerged.
Chapter 13
Necessity's Mother
Why so many people assume that Eurasians were superior to other peoples in inventiveness and intelligence ? Technological advancements seem to come disproportionately feoma few very very geniuses, such as Getenberg, James Watt, Edison and Wright brothers - they were Europeans or descendants of European emigrants to America.
All recognized famous inventors had a capable predecessors and successors and made their improvements at a time when society was capable of using their products. Two main conclusions are that technology develop cumulatively, rather than in an isolated heroics acts, and that it finds most of its uses after it has been invented, rather than invented to meet a foreseen need.
What is it that promotes an invention'a acceptance by a society ?
(1) relative economic advantage compared with existing technology. (2) social value and prestige, which can overcome economic benefit. (3) compatibility with vested interests ex- QWERTY keyboards, wheels, designer jeans etc.
How do differences in receptivity among societies arise ? (rural third world countries are less receptive to innovation that are western societies) laundry list fo 14 factors
1. life expectancy which in principle should give prospective inventors the years necessary to accumulate technical knowledge, as well as patience and security
2. Availability of cheap labour
3. Patents and other property laws, protecting ownership of inventors
4. Modern capitalism is and ancient Roman were not, organized in a way that makes it potentially rewarding to invest capital in tech advancements
5. strong individualism societies allow successful inventors to keep earning for themselves, whereas in other societies with strong family ties ensures that if someone starts earning then others will move in.
6. modern industrial society provided extensive opportunity to invest in technical training
7. Risk taking behaviour, is more widespread in some societies than in others.
8. the scientific outlook is a unique feature of post renaissance European societies
9. Tolerance of diverse views and of heretics fosters innovation
10. Religion vary greatly in their relation to tech innovations
following 4 sometimes stimulate or inhibit tech:
11. war
12. strong centralized society boosted technologies
13. Cimate
14. Resource abundance

Medieval Islam was tech advanced and open to innovation. It achieved far higher literacy rates than contemporary Europeans. Similarly is China. Thus, it is untrue that there are continents whose societies have tended to be innovative and continents whose societies have tended to be conservative. On any continent at any given time, there are innovative societies and also conservative ones. In addition, receptivity to innovation fluctuates in time within the same region.
The relative importance of local invention and of borrowing depends mainly in two factors - ease of invention of the particular tech, and the proximity of the particular society to other societies. In these societies tech developed most rapidly, bec they accumulate not only their own inventions but also those of the other societies. For example - medieval Islam, centrally located in Eurasia, acquired inventions from India and China and inherited ancient Greek learning.
Tech begets more tech, the importance of an inventions's diffusion potentially exceeds the importance of the original invention. Tech history exemplifies what is termed as autocatalytic process. Reason for autocatalytic (1) advances depends upon previous mastery of simpler problems (2) new tech and materials make it possible to generate still other new tech by recombination.
 In the long history of accelerating development, one can single out 2 esp. significant jumps - a. between 100k to 50k years ago, probably was made possible by genetic changes in our bodies: mainly evolution of modern anatomy permitting speech and modern brain function b. Our adoption of sedentary lifestyle, which happened at different times at different parts of the world. It was decisive since it enabled people to accumulate non portable possessions.
Variation in 3 factors - time of onset of food production, barriers to diffusion and human population size - led straightforward to the observed intercontinental differences in the development of technology. Eurasia is worlds largest landmass, encompassing largest number of competing societies. It also has two earliest known food production areas Fertile Crescent and China. Its east-west major axis permitted many inventions adopted in one part of Eurasia to spread relatively rapidly to societies at similar lat-long and climates elsewhere in Eurasia. The geographical and ecological barriers were less.
The differences in population are glaring: Eurasia is nearly 6 times than that of Americas, 8 times that of Africa, and 230 times that of Australia.

Chapter 14
From Egalitarianism to Kleptocracy
Types of societies
a. Band - dozen people - nomadic - egalitarian govt.
b. Tribe - hundreds - 1 fixed village - egalitarian govt. or one big man
c. Chiefdom - thousands - 1 or more fixed village - centralized hereditary
d. State -over 50k - many villages - centralized
A prerequisite for living in settlements in either food production or else a productive environment with especially concentrated resources that can be hunted and gathered within a small area.
Chiefdoms introduced the dilemma fundamental to all centrally governed, nonegalitarian societies. At best, they do good by providing expensive services impossible to contract for on an individual basis. At worst, they function unabashedly as kleptocracies, transferring net wealth from commoners to upper class.
What should an elite do to gain popular support while still maintaining a more comfortable lifestyle than commoners? Kleptocracy throughout the ages has been resorted to a mixture of 4 solutions -
1. Disarm the populance, and arm the elite.
2. Make the masses happy by redistributing much of the tribute received, in popular ways.
3. Use the monopoly of force to promote happiness, by maintaining public order and curbing violence.
4. To construct an ideology or religion that justifies Kleptocracy. Besides justifying the transfer of wealth to Kleptocrats, institutionalized religion also brings two other important benefits to centralized societies - (A) shared ideology solves the problem of how unrelated individuals are to live together without killing each other. (B) it gives people a motive, other than genetic self-interest, for sacrificing their lives on behalf of others.
Part of the reason for states triumph over simpler entities when two collides is that state usually enjoy an advantage of weaponry and other technologies, and a larger numerical adv. in population. But there are also two other potential adv. inherent in chiefdoms and states- a. centralized decision maker has the adv. at concentrating troops and resources. b. official religions and patriotic fervor of many states male their troops willing to fight suicidally.
How did small, non centralized, kin based societies evolve into large centralized ones in which most members are not closely related to each other ? There are multiple views but as per the writer - the size of the regional population is the strongest single predictor of social complexity. But the correlation do not tell us precisely how population variables function in a chain of cause and effect whose outcome is a complex society. To answer, examine how large dense population arise themselves - they arise only under the condition of food production, or at least under exceptionally productive conditions for hunter gathering. Food production contributes in at least 3 ways to specific features of complex societies -
1. It involves seasonally pulsed inputs of labor. Once food production has been done, labor can be utilized in other public works of society or to undertake wars etc.
2. food p may be organized so as to generate food surplus, which permits economic specialization and social stratification. The surplus can be stored to feed all tiers of a complex society: the chiefs, bureaucrats etc.  and other non food producing members
3. f p permits or require people to adopt sedentary living, which is a prerequisite for developing tech, crafts and public construction.

But that dosent prove that f p and large population make complex societies inevitable. 4 observationa=s that band or tribes organization does not work for thousands of people and that all existing large societies have complex centralized organization ?
1. problem of conflict between unrelated strangers. No one knows everyone to stop a feud.
2. growing impossibility of communal decision making with increasing population. A large society must be structured and centralized if it is to reach decision effectively.
3.  economic consideration - large societies can work if they have a redistributive economy.
4. large population density
Considerations of conflict resolutions, decision making, economies and space thus coverage in requiring large societies to be centralized.

But how small societies actually evolve or amalgamate into large societies ?
Amalgamation can happen in either of the two ways - under the threat of external force and actual conquest. Why should wars cause amalgamation of societies when density is dense but not when sparse ? The answer is that the fate of defeated people depends on population density, with three possible outcomes -
a. when density is low - survivors of the defeated group need only move farther away from their enemies.
b. when density is moderate - no area is available for defeated to flee. Tribal societies without food p  have no employment for slaves and do not produce food surplus to be able to yield much tribute, hence the victors have no use to keep them, apart from their wives.
c. where density is high - defeated can be used as slaves. since they have extensive food production, keep them as slave, and amalgate their society.

Thus food P and competition and diffusion between societies, led as ultimate cause via chains of causation that differed in detail but that all involved large dense population are sedeantary living, to the proximate agents of conquest: germs, writing, technology, and centralized political organization. Because those ultimate causes developed differently on different continents, so did those agents of conquest. Hence those agents tended to rise in the association with each other, but the association was not strict.

Part 4
Around the world in six chapters
Chapter 15
Yali's People
Australia stands out amongst all other continents as it is by far the driest, smallest, flattest, most infertile, climatically most unproductive, and biologically most impoverished. It is the only continent where in modern times all native people still lived without any of the hallmarks of the so called civilization - without farming, herding, metals, bows, and arrows, substantial buildings, settled villages, writing, chiefdom, or states. Yet as of 40k yrs ago, native aus societies enjoyed a big head start over societies of Europe and other continents. They developed some of the earliest known stone tools, watercraft, oldest known painting on the wall. Why, despite the head start, did E end up conquering A, rather than vice versa ?

It is now generally acknowledged that agriculture arose independently in the New Guinea highlands by domestication of NG wild species. It joins the fertile crescent and china and a few other regions. NG are an island of dense farming populations. Lowlands NG on the seacoast and rivers are villagers depending heavily on fish, while those on dry grounds away from coast and rivers subsist at low densities by slash and burn agriculture supplemented by hunter gatherings. In contrast lowland NG live as nomadic HG dependent on the starchy pith of wild sago palms, which are very productive and yield 3 times more calorie / hr of work than does gardening. NG swamps thus provide clear instance of an environment where people remained HG bec farming could not compete with  the HG lifestyle. Lowland exemplifies band organization. The farmers and the fishing people were the ones to develop more complex tech, societies and political org. They live in permanent villages and tribal societies, often led by a big man, some times they construct elaborately decorated houses.

However from an E perspective NG still rates as primitive rather than advanced. Why did they continue to use stone tools instead of developing metal tools, remain illiterate, and fail to organize them selves into chiefdoms and states? It turns out NG has several biological and geographical strikes against them. -
1. Although indigenous food production did arise in NG highland, the dietary staples were low protein root crops and production of sole domesticated animal species (pigs and chicken) was too low to contribute much to peoples protein budgets. Since neither pigs nor chicken can be harnessed to pull carts, highlanders remained without sources of power other than human muscle power, and also failed to evolve epidemic diseases to repeal the eventual E invaders.
2. Size of highland population was available in limited area.
3. 4k - 9k - was the sole altitude suitable for intensive food production; none above 9k and below 4k. Thus large scale economic exchange of food, bet communities at different levels did not happen - thus not providing pople with more balanced diet and promoting regional and economic integration.
For all the above reasons the pop did not reach more than 1000k. And with mere 1000k people NG could not develop the technology, writing, and political systems that arose among the tens of millions in China, the Fertile Crescent, the Andes and the Mesoamerica. Besides there were geographic isolation also restricting the inflow of technology and ideas from elsewhere.

But Australia was further primitive as compared to NG. Australia did not develop both animal husbandry or farming. During the Ice age many candidates of animal husbandry disappeared in wave of extinction. That left Australia, like NG, with no domesticable native mammals. Agriculture was another nonstarter which is not only the driest continent but also the most infertile, along with irregular nonannual climate cycle ENSO (el nino southern oscillation). If in good year HG had settled in villages, grown crops, and produced babies, those large population would have starved and died off in drought years, when the land could support fewer people. The other major obstacle to the development of food p in A was the paucity of domesticable wild plants.
Thus nomadic, HG lifestyle and minimal investment in shelter were sensible adaptation to A ENSO driven resources unpredictability. When local conditions deteriorated Aborigines, simple moved to an area where conditions were temporarily better. Rather than depending on just a few crops that could fail, they minimized the risk by developing an economy based on the great varieties of wild foods, not all of which were likely to fail simultaneously.
The Aboriginal A substitute for food p has been termed as 'firestick farming'. The A modified and managed the surrounding landscape in ways that increased its production of edible plants and animals, without resorting to cultivation.
Why did A did not develop metal tools, writing etc ? A major reason is that A remained HG, thus pop density was less. Along with aridity, infertility, and climate unpredictability. compare with millions of people living in other areas.
It merely proves to reflect the ubiquitous role of geography in the transmission of human culture and technology.
Since E had the oceangoing ships and compasses to travel to NG, they conquered the NG. But they did not replace the original native people as they did in other regions, why ? A major factor was malaria and other tropical diseases, none of them are acute epidemic crowd infections.
But why E germs did not infect NG ? One lucky break for NG was that there were no permanent E settlement in NG until 1880s, by which time public health discoveries had made progress in bringing smallpox and other infections diseases of E population under control. In addition the Austronesian expansion had already been bringing a stream of Indonesian settlers and traders to NG for 3500 years. Since Asian mainland infectious diseases were well established in Indonesia, NG thereby gained long explore and built up much more resistance to E germs than did Aboriginal Aus. The remaining obstacle to E would be settlers was that E crop, livestock and subsistence methods do poorly everywhere in the NG environment and climate.

Why did Aborigines fare so much worse than NG?
The basic reason is A suitability for E food p and settlement, combined with the role of E guns, germs, and steel in clearing A out of way. While some areas pose difficulty, most productive or fertile areas can nevertheless support E farming. A in the A temperate zone is now dominated by the Eurasian temperate zone staple crops of wheat etc.

Thus the development of food p in A had to await the arrival of non native crops and animals domesticated in climaticallly similar parts of the world until brought by transoceanic shipping. A obviously stood in their way, so they were either shot down, or killed by germs such as smallpox, influenza, measles etc.

White english colonists did not create a literate, food p, industrial democracy in A. They instead, they imported all of the elements from outside A: the livestock, all of the crops, the metallurgical knowledge, the steam engines, the guns, the alphabets, the political institutions and even the germs. All these were the end products of 10k years of development in Eurasian environment.

Chapter 16
How China became Chinese
Today China appears politically, culturally and linguistically monolithic to atleast lay people. It was already unified politically in 221 BC and has remained so far for most of the centuries since then. Of China's 1.2 billion people, over 800 million speak Mandarin, by far the largest number of native speakers in the world. China has been Chinese, almost from the beginning of its recorded history.
North and South Chinese are genetically and physically rather different: NC are most similar to Tibetians and Nepalese, taller heavier, paler, with more pointed nose and with smaller eyes that appear more slanted while SC are similar to Vietnemese and Filipinos. N and S China differ in environment and climate: N is drier and colder, the south wetter and hotter. How did these people nevertheless ended up with the same or very similar languages and cultures? What happened to the tens of thousands of distinct languages that must have arisen in China over that long time span?

Chapter 18
Speedboat to Polynesia
South Chinese developed indigenous food production and technology, received writing and still more technology and political structures from N China, and went on to colonise tropical SE Asia and Taiwan, largely replacing the former inhabitants of those areas. Within SEAsia, among the descendents or relatives of those food-producing South C colonists, the Yumbri in the mountain rain forests of NE Thailand and Laos reverted to living as hunter gatherers, while the Yumbri'c close relatives the Vietnemese remained food producers in the rich Red Delta and established a vast metal based empire. Similarly, among Austronesian emigrants farmers from Taiwan and Indonesia, the Punan in the rain forests of Borneo were forced to turn back to HG lifestyle, while their relatives living on Java'a rich volcanic soils remained food producers, founded a kingdom under the influence of India, adopted writing and built the great Buddhist monument of Borobudur. The Austronesians who went on to colonize Polynesia became isolated from E Asian metallurgy and writing and hence remained without writing or metals.

Chapter 18
Hemispheres Colliding
The largest population replacement of the last 13k years has been the one resulting from the recent collisions between Old World and New World societies. Its most dramatic and decisive moment, occured when Pizarro's tiny army of Spaniards captured the Inca emperor Atahuallpa, absolute ruler of the largest, richest, most populous and administratively and technologically most advanced Native American state. Why did E reach and conquer the lands of Native Americans, instead of vice versa ? Our starting point will be a comparison of Eurasian and Native Americans societies as of AD 1492, the year of Columbus's discovery of the Americas.
The most glaring differences between A and Eurasian food production involved big domestic mammal species. Eurasia had 13 species, while A has only one species of big domestic mammal, the Ilama/alpaca, confined to a small area of the Andes and the adjacent Peruvian coast. While it was used for meat, wool, hides and goods transport, it never yielded milk for human consumption, never bore a ride, never pulled a cart or a plow, and never served as a power source or vehicle of warfare. Thats enormous set of differences between Eurasians and Native Americans societies - due largely to the Late Paleistocene extinction (extermination?) of most of the N and S America's former big wild mammal species.
E and A also differed with respect to plant food production, thought the disparity here was less marked than for animal food production.
In those parts of theA that did support N A agriculture, it was constrained by five major disadvantages vis a vis E agriculture  a. widespread dependency on protein poor corn instead of E's diverse and protein rich cereals b. hand plantings of individual seeds, instead of broadcast sowing c. tilling by hand instead of plowing by animals, which enables one person to cultivate a much larger area, and which also permits cultivation of some fertile but tough soils and sods that are difficult to till by hand d. lack of animal manuring to increase soil fertility e. just human muscle power instead of animal power, for agri tasks such as threshing, grinding, and irrigation. These differences suggest that on E agri as of 1492 may have yielded on the average more calories and protein per person-hour of labour than NA agri did.
Among the resulting proximate factors behind the conquest, the most important included differences in germs, tech, political org, and writing. Of these, the one linked most directly to the differences in food production was germs.
Rivaling germs as proximate factors behind E's conquest of the A were the differences in all aspects of the technology. These differences stemmed ultimately from E much longer history of densely populated, economically specialised, politically centralised, interacting and competing societies dependent on food production. Five areas of tech may be singled out:
1. metals - initially copper, the bronze, and finally iron - were used for tool in all complex E societies as of 1492. In contrast, stone and wood and bone were still principal materials for tools in all NA societies.
2. Military tech - was far more potent in E. E weapons were steel swords, lances, and daggers, supplemented by small firearms and artillary, while body armour and helmets were also made of solid steel or else of chain mail. NA used clubs and axes of stone or wood (occasionally copper in the Andes) slings, bows and arrows, and quilled armor.
3. E societies enjoyed huge advantage in their source of power to operate machines. Use of animals instead of human muscle power. and other advantages.
4. E socities developed large sailing ships equipped with sextants, magnetic compasses and cannons etc.
5. E and NA differed in their political org also. By late medieval and Renaissance times, most E had come under the rule of organized states. The A has 2 empires, those of the Aztecs and Incas. 7 E states Spain, Portugal, England, France, Holland, Sweden and Denmark had the resources to acquire A colonies between 1492 and 1666.
6. Most E stated has literate bureacuracies, and some significant proportion of the populance other than bureaucrats were also literate, where as use of writing in A was confined to the elite in a small area of Mesoamrica

Why were the trajectories of all key developments shifted to later dates in A than in E? 4 groups of reasons suggest themselves; the later start, more limited suite of wild animals and plants available for domestication, greater barrier to diffusion, and possibly smaller or more isolated areas of dense human populations in the Americas than the E.
In addition to E's head start and wild animals and plant species, developments in E were also accelerated by the easier diffusion of animals, plants, ideas, technology ans people in E than in the A, as a result of several sets of geographical and ecological factors. E ease-west major axis, unlike the As north-south major axis, permitted diffusion without change in latitude and associated environmental variables.
Three set of ultimate factors that tipped the advantage to E invaders of the A: E's long head start on human settlement; its more effective food production, resulting from greater availability of domesticable wild plants and esp of animals; and its less formidable geographic and ecological barriers to intracontinental diffusion. A 4th, more speculative ultimate factor is suggested by some puzzling non-inventions  in the A: the non-inventions of writing and wheels in complex Andean society.
In the conquest E transmitted epidemics (probably smallpox) made major contributions, by killing the emperors themselves, as well as a large fractions of the population.
As for the most advanced native societies of NA, those of the US SE and the Mississippi River system, their destruction was accomplished largely by germs alone, introduced by early E explorers.

Chapter 19
How Africa became Black
Even before the arrival of white colonialists, Af already harbored not just black but 5 of the world's 6 major divisions of humanity, and three of then are confined to natives to Af. 1/4th of the world's languages are spoken only in Af. No other continent approaches this human diversity.
Af diverse people resulted from its diverse geography and its long prehistory. Af is the only continent to extend from the northern to the southern temperate zone, while also encompassing some of the w's driest deserts, largest tropical rain forests, and highest equatorial mountains. Human have lived in Af far longer than anywhere else: our remote ancestors origianated there around 7 mn years ago, and anatomically modern Homo Sapiens may have arisen there since then. The long interaction between Af's many peoples generated its fascination prehistory, including two of the most dramatic population movement of the past 5k years - the Bantu expansion and the Indonesian colonization of Madagascar. All of those past interactions continue to have heavy consequences, bec the details of who arrived where before whom are shaping Af today.
How did those 5 divisions of humanity get to be where they are now in Af? Why were blacks the one who came to be so widespread, rather than the 4 other groups whose existence Am tend to forget? Af prehistory is a puzzle ona grand scale, still only partly solved.
The 5 major human groups to which Af was already home by 1000AD are those loosely referred to by laypeople as blacks, whites, Africans Pygmies, Khoisan and Asians. These 5 constitute or represent all the major divisions of humanity except for Aboriginal Australians and their relatives.
The large island of Madagascar lies only 250 miles off the East Afican coast, much closer to Af than to any other continent. The language spoken by all the people of M - Asians, blacks and all mixed - is Ausronesian and very similar to the Ma'anyan language spoken on the Indonesian island of Borneo, over 4000 miles across the open Indian Ocean from M. No other people remotely resembling Borneans live within thousands of miles of M. These Austronesians, with their Aus language and modified Aus culture, were already established on M by the time its was first visited by E in 1500. This is as astonishing fact of human geo for the entire world.

The studies suggest that Afroasiatic languages arose in Af, and that only one branch of them spread to the Near East. Hence it may have been Af that gave birth to the languages spoken by the authors of the Old and New testament and the Korans, the moral pillars of Western civilization.
When E reached sub-Saharan Af in the 1400s Af were growing 5 sets of crops each of them laden with significance for Af history. North Af enjoys mediterranian climate same as the FC, where agriculture arose. Hence NAf's original crops all prove to be ones adapted to germinating and growing with winter rains, and known from archeological evidence to have been first domesticated in the FC beginning around 10k years ago. Those FC crops spread into climatically similar adjacent areas of NAf and laid the foundation for the rise of ancient Egyptian civilization. They include such familier crops as wheat, barley, peas, beans and grapes. These are familiar to us precisely because they also spread into climatically similar adjacent areas of E, thence to Am and Aus, and became some of the staple crops of temperate-zone agr around the world.
As one travels south in Af across the Saharan desert and reecounters rain in teh Sahel zone just south of the desert, one notices that rain fall in the summer rather than in the winter. Even if FC crops adopted to winter rain could have somehow crossed the Sahara, they would have been difficult to grow in the summer-rain Sahel zone.
Bananas, Asians yams, and taro were already widespread in sub-saharan Af in the 1400s and Asian rice was established on the coast of East Af. But those crops originated in tropical SE Asia. Their presence of Af would astonish us, if the presence of Indonesian people on M had already alerted us to Af prehistoric Asian connection. Did Aus sailing from Borneo land on the E Af coast, bestow their crops on grateful Af farmers, pick up Af fisherman, and sail off into the sunrise to colonize M, leaving no other Austonesian traces to Africa ?
Not a single Af crop originated south of it. Southern Af widl plants were mostly unsuitable for domestication. E entering Af enjoyed the triple adv of guns and other technology, widespread literacy, and the political org necessary to sustain expensive programs of exploration and conquest.
But why did E develop those three adv before sub-Saharan Af could ?
Food production was delayed in sub-saharan Af (compared to Eurasia) by Af's paucity of domesticable native animal and plant species, its much smaller area suitable for indigenous food prod, and its NS axis, which retarded the spread of food production and inventions. Let;s examine how those those factors operated. 1. Domestic animals did not reach sub-saharan until thousands of years after they began to be utilised by emerging E civilisations. Af equivalents of such as Af buffalo, zebra, bush pig, rhino, and hippo have never been domesticated, not even in modern times.
2. Af earliest agri may have begun several thousands of years later than that of FC. 3. Af area is only about half that of Eurasia. 4. SW axis hence crops and animals domesticated or acquired in one part of Af had great difficulty in moving to other parts.
In short, E's colonization of Af had nothing to do with differences bw E and A people themselves, as white racists assume. Rather, it was due to accidents of geography and biography - in particular, to the continent's different areas, axes, and suites of wild plants and animal species. That is, the different historical trajectories of Af and E stem untimately from difference in real estate.

Chapter 20
Who are the Japanese ?
The end of the Ice Age was accompanied by the first of the two most decisive  changes in Japanese history - the invention of pottery. - watertight containers, boil, steam, they gained access to abundant food resources that had previously been difficult to utilize; leafy vegetables whcih would burn or dehydrate if cooked over a fire; etc. Worlds oldest known pottery was made in Japan in 12700 years ago. Japanese potters were clearly hunter gatherers as Japanese environment is so productive that it was one of the few locations were people could settle down and make pottery while still living as hunter gatherers. Pottery helped those Jap HG to exploit their env's rich food resources more than 60k years before intensive agri reached Jap. These resulted in first population explosion. The other, which triggered second, began around 400 BC with the arrival of new life style from South Korea. Immigrants from Korea really did make a big contribution. the balance got tipped in their favor coz of 4 factors - the development of  irrigated rice agri, instead of less productive dry field rice agri; the continuing improvement of rice strains adapted to a cool climate; the growth in Koreas farming population, putting pressure on Koreans to emigrate and the development of iron tools for efficiently mass producing the wooden shovel, hoes, and other tools for rice paddy agri.
The conclusion is likely to be equally unpopular in Japan and in Korea, bec of the current mutual dislike of those two peoples. Reluctant as Japanese and Koreans are to admit it, they are like twin brothers who shared their formative years.

Epilogue
The Future of Human History as a Science
The continents differ in innumerable env features affecting trajectories of human societies. Just 4 sets of differences appear to be most important ones
1. Continental differences in the wild plants and animal species available as starting material for domestication. thats bec food prod was critical for the accumulation of food surplus that could feed non food producing specialists, and for the building of large population enjoying a military advantage through mere numbers even before they had developed any technological or political advantage. For both of those reasons, all developments of economically complex, socially stratefied, politically centralized societies beyond the level of small nascent chiefdomm were based on food production.
In the case of technological innovation and political institutions as well, most societies much more from other societies than they invent themselves. This diffusion, and migration wtihin a continent contribute importantly to the development of its societies, which tend in the long run to share each other's development.
2. 2nd factor consists of those affecting the rates of diffusion and migration, which differed grately among continents. They were most rapid in Eurasia, bec of its EW major axis and its relatively modest ecological and geographical barriers.
3. 4. Continental diff in area and total population size. A larger area or pop means more potential inventors, more competing societies, more innovations available to adopt.
FC and Eastern Mediterranean societies had the misfortune to arise in an ecologically fragile environment. They committed ecological suicide by destroying their own resource base.
Why did China also lose its lead ? Fleets were suspended as a result of a typical aberration of local politics that could happen anywhere in the world: a power struggle between two factions at the chinese court (the eunuchs and their opponents) THe former faction had been identified with sending and captainign the fleets. Hence when the latter faction gained the upper hand in a power struggle, it stopped sending fleets, eventually dismantled the spipyard, and forbade ocengoing shipping. The episode is reminscent of the legislation that strangled development of public electric lighting in London in the 1880s, the isolationism of the US bw the first and second WW and any number of backward steps in any country all motivated by local politics. but in China there was a difference, bec the entire region was politically unified. One decision stopped fleets over the whole of China. That one temporary decision became irreversible, bec no shipyard remained to turn out ships that would prove the folly of that temp decision, and to serve as a focus for rebuilding other shipyards.

In fact, precicely bec E was fragmanted, Columbus succeeded on his 5th try in persuading one of E's hundreds of princes to sponsor him. These consequences of E's disunity stand in sharp contrast to those of C's unity. From time to time the chinese court decided to halt other activities besides overseas navigation: it abandoned development of an elaborate water driven spinning machine, stepped back from the verge of industrial revolution in th1 4th century, demolished or virtually abolished mechanical clocks afterleading the workld in cliock constr and retreatedfrom mech device and tech in general after the late 15th century.Those potentially harmful effects of unity have flared up again in modern CHina, notably during tje ,adness of the Culturl Revlolution in the 1960 /70s when a decision by one or a few leaders closed the whole country's school system for five years.
throughout the book emphasis on the diffusion of technology that takes place in the absence of formidable barriers. But China's connectedness eventually became a disadvantage, bec a decision by one despot could and repeatedly did halt innovation. In contrast, E's geographic balkanization resulted in dozens or hundred of independent, competing stateless and centres of innovation. If one state did not pursue some particular innovation, another did, forcing neighbouring states to do likewise or else be conquered or left economically behind.

2017 Afterword
Rich and Poor Countries In the Light of Guns, Germs and Steel
S Korea vs N Korea / W and E Germany - these comparisons provide compelling evidence that differences in institution can indeed produce big differences in national wealth, even in the near absence of geographic differences. Some economists then generalize / over generalize to conclude that institutions are the major factor explainign why some countries are rich and other countries are poor.
When economists talk specifically about what they term 'good institutions' that motivate people as individuals to work in ways leading to the buildup of national wealth. THey include: control of inflation, educational oppertunities, effectiveness of governance, enforcement of contracts, freedom from trade barriers, incentives and oppertunities for investment of capital, lack of corruption, low risk of assassination, open currency exchange, protection of private property rights, rule of law, and unimpeded flow of capital.
Other factors besides good inst. contribute to the wealth of nations - esp geographic factors. A tropical location has two characteristics that are bad for the economy. One of those characteristics is familiar to any readers who live in the tropics or have taken a vacation there; you're more likely to get sick in the tropics than in the temperate zone, either from tropical infectious diseases like malaria or dengue fever or else from tropical parasites. Hence people in tropical countries spend more time sick and unable to work than people in temperate countries. Other disadvantage is lower agriculture productivity, due to more infertile soils and more plant and animal diseases.