JARED DIAMOND, a researcher at UCLA, has been doing fieldwork in New Guinea for over 25 years. New Guinea is home to some of the last hunter-gatherers in the world. A long time ago, one of his New Guinea friends asked Diamond why white people had so much and New Guineans had so little.

That's an obvious question, but Jared was surprised to realize he didn't know the answer. In fact, he didn't know of anyone who knew the answer. When Europeans were busy conquering the Americas and Australia and New Zealand and parts of Asia and Africa, the obvious answer was that white people were superior. Either they were genetically superior, or their culture was superior. They were smarter or more capable. That explanation is clearly bad, but a good one has failed to take its place.

Why did Europeans conquer the world? Why, when Europeans came into contact with other places in the world, did they almost always conquer?

Jared Diamond had spent enough time with the New Guineans, living among them, to know that they were intelligent and resourceful people — in Diamond's opinion, more intelligent and resourceful than people living in modern societies, both because of natural selection (unintelligent and unresourceful people don't live long in the New Guinea wilds) and because their environment is so difficult that they smarten up as they grow up, or they don't make it to adulthood.

If they are so smart, why hadn't they invented guns? Why hadn't they forged steel? Why were they so outmatched when Europeans landed on their island?

Diamond decided to find out why. And the way he started was a stroke of genius. He decided to go back to a time in history when all humans were equal. About 13,000 years ago all humans on earth were hunter-gatherers. No group had much more than any other group. There were no civilizations, no cities, no rich people. They all had pretty much the same technology. Then what happened?

The first thing that changed was the domestication of animals and plants. Agriculture. That is the beginning of global inequality because agriculture wasn't invented everywhere on earth at the same time. Some places started earlier than others. The first place people started farming and tending animals was in the Fertile Crescent in the Middle East near present-day Syria, Jordan, and Iraq. Agriculture was invented in other parts of the globe much later. The people on the Eurasian continent got a huge head start. They started farming 2000 years, 4000 years, and in some cases 6000 years earlier than other places!

Now the question is again, why? Were people on other continents not as bright? Why didn't they start farming earlier? The answer is that in order for a people to settle down to agriculture, they need a complex combination of factors, and those factors happened to arise first in the Fertile Crescent. By the pure luck of geography. Those people happened to be living in the right place at the right time.

WHAT IT TAKES TO START AGRICULTURE

Some groups of hunter-gatherers in New Guinea are semi-farmers. They cultivate banana trees. But they don't stay put. They haven't settled down and built cities. They haven't settled down at all because their farming has never allowed them the opportunity to put down roots. They have to keep moving. They come back a couple of times in the year, once to pull weeds, and once to actually harvest the bananas, but they have to keep moving in order to get enough to eat. Why?

The reason is simple: You can't store bananas. Finding a food source isn't enough. It has to be the right kind of food source. Not only that, but bananas have very little protein. People can't live on it. They have to eat other things. It turns out that in the Fertile Crescent, wheat grew wild. It lent itself to domestication in many ways, and because the growing season was so short in that area, the seeds were rather large and had evolved to be able to remain dormant for a long time. In other words, here was a food you could store for a long time and it wouldn't rot. It also is pretty high in protein.

Jared Diamond and many others have scoured the globe for other potential plants that could fulfill the same requirements. They are very rare.

Not only that, but even a storable plant seed wasn't enough to switch from hunter-gatherers to farmers. They also needed an animal. They needed a good source of protein. People don't survive very well eating only grain, s wheat was not enough. And again, just by luck, in the Fertile Crescent, there was an animal that could be domesticated, and again, that wasn't true in most other parts of the world.

Wherever farming has taken hold, the farmers had at least one domesticated animal to provide protein, at least one storable source of carbohydrates, and a legume (peas, lentils, beans, etc.). Legumes are also storable. They dry hard and don't rot readily. And they are higher in protein than grains, so they can be used as a protein supplement if animal protein becomes scarce.

With enough sustainable food like this, people could stop roaming, and form villages.

There are very few places in the world where a domesticatable animal, plus a storable carbohydrate, plus a legume all exist in the same place. Can you see why it is not enough just to have one of these items? If all you had was one, it wouldn't be enough food to sustain you. There are places in the world where a grain grows. But farming didn't start and people didn't settle down because that isn't enough. You need the combination, and it was rare. But it was there in the Fertile Crescent, and it allowed people to settle down into villages.

That was the beginning. It doesn't seem like much, but agriculture brought into existence a whole chain of effects that allowed the farmers to advance their technology far beyond hunter-gatherers.

THE CHAIN OF EFFECTS

Here's what happened: People settled down. They had a more reliable source of food throughout the year (because was is storable), so they had more kids. A hunter-gatherer woman only has a kid every five years or so because hunter-gatherers move around a lot and until a child can walk on his own at a pretty good pace, the mother cannot afford to have another child. But once people settle down into a village with a steady supply of food, they start having children at a rate close to one per year.

So the population of farmers grew faster than hunter-gatherers, allowing the farmers to outnumber and defeat hunter-gatherers in war.

Also, because settled farmers are settled, they can have more possessions, like tools and weapons. Hunter-gatherers had to carry their stuff with them, so they were limited in how many possessions they could accumulate. This has a long-term limiting effect on the development of new technologies because often new inventions are built on previous inventions. Because a hunter-gatherer was limited to what he could carry (among other reasons), his technologies stayed simple and didn't increase or improve very quickly.

As farming techniques improved, the farmers had more food excess to store, so some people no longer had to do the work of producing food. Specialists could then develop. Tool makers. Weapons makers. And because they were specialized and spent more time on their craft, they invented more. Technology improved faster.

So they had better weapons and greater numbers and could defeat hunter-gatherers even more effectively.

Another very important factor is this: The more people you have together, the more ideas are exchanged. And when people don't have to spend their working days getting enough to eat, they become more inventive. The process of innovation began to accelerate when people settled down into towns and cities.

Hunter-gatherers hardly changed at all. They were relatively isolated groups of not very many people who didn't have the time or incentive to invent new technologies, and so their technologies remained relatively unchanged for thousands of years.

LATITUDE

One important advantage the Eurasians had was a large piece of land stretching across the same latitude. So the combination of the domesticated plants and animals could (and did) spread east to Asia and west to Europe. There was constant interchange between these far flung places, also accelerating the process of invention.

In the Americas, Australia, and Africa, the spreading was much more limited along the same latitude. The reason latitude is important is that if you go east or west at the same latitude, you have similar lengths of day, somewhat similar climate and weather, which means plants and animals that survive well at one spot are more likely to survive well east or west of there, but not usually north or south of that spot.

Also, there were significant barriers to traveling north and south in Africa and the Americas. Huge deserts and impenetrable forests prevented one area from having much contact with other areas. So, for example, in Mesoamerica, they had invented the wheel. Down in South America, they had domesticated llamas. The people in Mesoamerica never got the llamas and the South Americans never got the wheel.

So the width of the Eurasian continent is a huge factor in the acceleration of technology. But there was another factor that gave the Europeans a back-breaking advantage when they encountered Native Americans and Africans (and Hawaiians and Australian Aborigines, etc.). Whenever Europeans in the Age of Discovery encountered anyone from any other continent, they had an unbeatable weapon: Disease.

DISEASES

Why is it that when Europeans landed on the shores of the Americas that the Native Americans were devastated by so many diseases brought by the Europeans? Why didn't the Native Americans have their own diseases to give to the white man? Why did Europeans have such a huge collection of deadly diseases that they had a resistance to, but the Native Americans didn't have any diseases that the Europeans had no resistance to?

Interesting question, isn't it? The answer is that most of our diseases — smallpox, measles, tuberculosis, flu, etc. — originally came from the animals Europeans had domesticated.

Here's how it works: First, an animal has a microbe that infects it, say cowpox (an actual case). Because humans are hanging around cows a lot, some of the microbes jump to the humans, but generally speaking, they can't survive. But a little random mutation here and there and all of a sudden smallpox comes into existence and wipes out huge portions of the European population. It mutated to become a human disease. This happened again and again. Plague after plague swept through Europe over the centuries, killing off everyone who didn't have some resistance to it.

Native Americans hadn't hardly domesticated any animals. They didn't have cows, horses, pigs, chickens, goats, sheep, ducks, geese, oxen, donkeys, etc. But Europeans had all these any many more.

That's why the disease exchange was so one-sided. And those diseases helped Europeans tremendously in conquering other people.

WHY NOT THE CHINESE?

Okay, all of this explains why people on the Eurasian continent dominated people on other continents. But the Eurasian continent is very wide. Why wasn't it the people from the Middle East or China who did the conquering? Why was it Europeans?

The Middle East is too dry for intensive farming now. Most of the forests have been cut down and didn't grow back. The place is like a desert now, not like it was 13,000 years ago when agriculture was just getting started. So their ability to survive well, much less produce surplus food, diminished over time. At the time Europe began its Age of Discovery, around 1500 AD, the Middle East was past its prime and not in a position to compete.

China, on the other hand, could have been a potential rival for world exploration and dominance around 1500, but right about that time, the ruler of China decided to dismantle all the shipyards in China! No more exploration by sea, he said. One of the things that prevented China from being the people who conquered the other continents, in other words, was China's unity. A single ruler could decide the fortunes of the whole region. Not so in Europe.

Europe has lots of natural barriers: It is divided by water and mountains and lots of jutting landmasses. So Europe has been continually divided into states. In 1500, those states were all competing with each other. Even if you had a ruler or two who didn't want to explore the world, you would have other rulers who would, and they would become rich and essentially force the other states to jump in or fall behind (or even be conquered).

THE ANSWER

Our original question was, why did Europeans conquer the world? The answer is, because they happened to live on the Eurasian continent, so they were lucky enough to start agriculture earlier than any other place on earth. Just by luck, they were at the right latitude with the right combination of available animals and plants that could be domesticated. And with a head start of thousands of years, their technology was more advanced. And because of their close association with their domesticated animals, they carried many diseases to which they had resistance but people from other continents did not. Because of their head start, Europeans possessed guns, germs, and steel and they conquered the world with them.

Much of the global inequality seen today comes from this original source.

If you'd like to know more, Jared Diamond has written an excellent book and made a first-rate DVD about how Europeans conquered the world. Both are titled, Guns, Germs and Steel. Check them out. Diamond goes into far more interesting detail than I have here in this article.