Nature's Infinite Book 



Spacious Skies and Tilted Axes 



Why were plants domesticated so early in the Fertile Crescent? 

 And why did those crops then spread so far and so fast? 



by Tared Diamond 



On the map of the world, compare the 

 shapes and orientations of the continents. 

 You'll immediately be struck by an obvi- 

 ous difference. The Americas span a much 

 greater distance north to south (9,000 

 miles) than east to west (only 3,000 miles 

 at the widest, narrowing to a mere 40 miles 

 at the Isthmus of Panama). That is, the 

 major axis of the Americas is north-south. 

 That's also true, although to a lesser de- 

 gree, for Africa. In contrast, the major axis 

 of Eurasia is east-west. What effect, if any, 

 did those different orientations of the con- 

 tinents' axes have on human history? 



Merely posing this question may raise 

 some people's hackles. It seems to invite 

 the label "environmental determinism" — 

 a concept that is sometimes lampooned as 

 implying that human creativity counts for 

 nothing, and that cUmate irresistibly pro- 



grams us like computers. Naturally, geo- 

 graphic interpretations can be wrong or 

 carried to an extreme. But denying that ge- 

 ography influences the broad course of 

 history is equally extreme. 



Human societies have evolved at differ- 

 ent average rates on different continents 

 for at least the past ten thousand years. 

 Specifically, developments such as agri- 

 culture, metallurgy, writing, and empires 

 arose earliest in parts of Eurasia, arose 

 later in the Americas and sub-Saharan 

 Africa, and did not arise indigenously in 

 Australia. Such persistent patterns can 

 hardly be dismissed as accidents reflecting 

 where a few geniuses happened to be 

 bom. Bigots prefer to invoke supposed 

 differences in I.Q. among populations, but 

 have conspicuously failed to demonstrate 

 such differences. Instead, these broadest 



The World's Five Regions with Mediterranean Climate 



South Afmca 





Australia 



Mediterranean climate — mild, wet winters and hot, dry summers— favored the 

 evolution of big-seeded, annual plants. Such plant species, including the wild 

 ancestors of barley and wheat, were especially abundant in the Fertile Crescent (light 

 green). Arrows indicate the major axes of continents. 



patterns of history seem likely to have 

 arisen from influences of differing geo- 

 graphic factors. I believe fliat the enor- 

 mous, sometimes tragic, consequences of 

 those differences in the continents' axes 

 contributed greatly to tiie very different 

 treatment tiiat history has meted out to Na- 

 tive Americans, Africans, and Eurasians 

 in the last 500 years. 



My interest in this question has been 

 restimulated by a recently pubUshed, re- 

 vised edition of a wonderful book. Domes- 

 tication of Plants in the Old World, by Is- 

 raeli geneticist Daniel Zohary and 

 German botanist Maria Hopf. The book 

 concerns the early importance of that part 

 of Southwest Asia variously known as the 

 Fertile Crescent, or the Near East. This 

 area was the earUest site for a whole string 

 of developments, including towns, writ- 

 ing, empires, and what we term (for better 

 or worse) civilization. All those develop- 

 ments sprang, in turn, from the advent of 

 dense human populations and the rise of 

 food production — in the form of agricul- 

 ture and animal husbandry — that made it 

 possible to store food surpluses and feed 

 nonfarming speciaUsts. 



Since food production was the first of 

 the major innovations that arose in the Fer- 

 tile Crescent, anyone attempting to under- 

 stand the broad pattern of human history 

 must begin by trying to understand why 

 domestication started so early there. Why, 

 too, did it spread from there so fast and so 

 far? Zohary and Hopf are illuminating on 

 both points. 



The early start in the Fertile Crescent, 

 according to Zohary and Hopf, was due to 

 a combination of geographic, climatic, 

 and biotic factors. Western Eurasia (Eu- 

 rope plus Southwest Asia) includes die 

 world's largest zone of so-called Mediter- 



16 Natural History 5/94 



