Guns, Germs & Steel

Figure 15.1. Map of the region from Southeast Asia to Australia andew Guinea. Solid lines denote the present coastline; the dashed lines are e coastline during Pleistocene times when sea level dropped to below ^ Present stand-that is, the edge of the Asian and Greater Australian
ext>VeSj *,* ^^ time' NeW Guinea and Australia we Joined in anPonded Greater Australia, while Borneo, Java, Sumatra, and Taiwanere part of the Asian mainland.

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a few decades of colonizing a continent whose inhabitants after more than 40,000 years were still nonliterate hunter-gatherers? It is especially striking that Australia has some of the world's richest iron and aluminum deposits, as well as rich reserves of copper, tin, lead, and zinc. Why, then, were Native Australians still ignorant of metal tools and living in the Stone Age?
It seems like a perfectly controlled experiment in the evolution of human societies. The continent was the same; only the people were different. Ergo, the explanation for the differences between Native Australian and European-Australian societies must lie in the different people composing them. The logic behind this racist conclusion appears compelling. We shall see, however, that it contains a simple error.
As the first step in examining this logic, let us examine the origins of the peoples themselves. Australia and New Guinea were both occupied by at least 40,000 years ago, at a time when they were both still joined as Greater Australia. A glance at a map (Figure 15.1) suggests that the colonists must have originated ultimately from the nearest continent, Southeast Asia, by island hopping through the Indonesian Archipelago. This conclusion is supported by genetic relationships between modern Australians, New Guineans, and Asians, and by the survival today of a few populations of somewhat similar physical appearance in the Philippines, Malay Peninsula, and Andaman Islands off Myanmar.
Once the colonists had reached the shores of Greater Australia, they spread quickly over the whole continent to occupy even its farthest reaches and most inhospitable habitats. By 40,000 years ago, fossils and stone tools attest to their presence in Australia's southwestern corner; by 35,000 years ago, in Australia's southeastern corner and Tasmania, the corner of Australia most remote from the colonists' likely beachhead in western Australia or New Guinea (the parts nearest Indonesia and Asia); and by 30,000 years ago, in the cold New Guinea highlands. All of those areas could have been reached overland from a western beachhead. However, the colonization of both the Bismarck and the Solomon Archipelagoes northeast of New Guinea, by 35,000 years ago, required further overwater crossings of dozens of miles. The occupation could have been even more rapid than that apparent spread of dates from 40,000 to 30,000 years ago,

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since the various dates hardly differ within the experimental error of the radiocarbon method.
At the Pleistocene times when Australia and New Guinea were initially occupied, the Asian continent extended eastward to incorporate the modern islands of Borneo, Java, and Bali, nearly 1,000 miles nearer to Australia and New Guinea than Southeast Asia's present margin. However, at least eight channels up to 50 miles wide still remained to be crossed in getting from Borneo or Bali to Pleistocene Greater Australia. Forty thousand years ago, those crossings may have been achieved by bamboo rafts, low-tech but seaworthy watercraft still in use in coastal South China today. The crossings must nevertheless have been difficult, because after that initial landfall by 40,000 years ago the archaeological record provides no compelling evidence of further human arrivals in Greater Australia from Asia for tens of thousands of years. Not until within the last few thousand years do we encounter the next firm evidence, in the form of the appearance of Asian-derived pigs in New Guinea and Asian-derived dogs in Australia.
Thus, the human societies of Australia and New Guinea developed in substantial isolation from the Asian societies that founded them. That isolation is reflected in languages spoken today. After all those millennia of isolation, neither modern Aboriginal Australian languages nor the major group of modern New Guinea languages (the so-called Papuan languages) exhibit any clear relationships with any modern Asian languages.
The isolation is also reflected in genes and physical anthropology. Genetic studies suggest that Aboriginal Australians and New Guinea high-landers are somewhat more similar to modern Asians than to peoples of other continents, but the relationship is not a close one. In skeletons and physical appearance, Aboriginal Australians and New Guineans are also distinct from most Southeast Asian populations, as becomes obvious if one compares photos of Australians or New Guineans with those of Indonesians or Chinese. Part of the reason for all these differences is that the initial Asian colonists of Greater Australia have had a long time in which to diverge from their stay-at-home Asian cousins, with only limited genetic exchanges during most of that time. But probably a more important reason is that the original Southeast Asian stock from which the colonists of
reater Australia were derived has by now been largely replaced by other Asians expanding out of China.

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Aboriginal Australians and New Gumeans have also diverged genetically, physically, and linguistically from each other. For instance, among the major (genetically determined) human blood groups, groups B of the so-called ABO system and S of the MNS system occur in New Guinea as well as in most of the rest of the world, but both are virtually absent in Australia. The tightly coiled hair of most New Guineans contrasts with the straight or wavy hair of most Australians. Australian languages and New Guinea's Papuan languages are unrelated not only to Asian languages but also to each other, except for some spread of vocabulary in both directions across Torres Strait.
All that divergence of Australians and New Guineans from each other reflects lengthy isolation in very different environments. Since the rise of the Arafura Sea finally separated Australia and New Guinea from each other around 10,000 years ago, gene exchange has been limited to tenuous contact via the chain of Torres Strait islands. That has allowed the populations of the two hemi-continents to adapt to their own environments. While the savannas and mangroves of coastal southern New Guinea are fairly similar to those of northern Australia, other habitats of the hemi-continents differ in almost all major respects.
Here are some of the differences. New Guinea lies nearly on the equator, while Australia extends far into the temperate zones, reaching almost 40 degrees south of the equator. New Guinea is mountainous and extremely rugged, rising to 16,500 feet and with glaciers capping the highest peaks, while Australia is mostly low and flat—94 percent of its area lies below 2,000 feet of elevation. New Guinea is one of the wettest areas on Earth, Australia one of the driest. Most of New Guinea receives over 100 inches of rain annually, and much of the highlands receives over 200 inches, while most of Australia receives less than 20 inches. New Guinea's equatorial climate varies only modestly from season to season and year to year, but Australia's climate is highly seasonal and varies from year to year far more than that of any other continent. As a result, New Guinea is laced with permanent large rivers, while Australia's permanently flowing rivers are confined in most years to eastern Australia, and even Australia's largest river system (the Murray-Darling) has ceased flowing for months during droughts. Must of New Guinea's land area is clothed in dense rain forest, while most of Australia's supports only desert and open dry woodland.
New Guinea is covered with young fertile soil, as a consequence of volcanic activity, glaciers repeatedly advancing and retreating and scouring

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