Chapter 10 - Spacious Skies and Tilted Axes

Shikai Yan
College Writing R1A
Professor Peter Vahle

  Spacious Skies and Tilted Axes

- Why did food production spread at different rates on different continents?

In this chapter, Jared Diamond investigates the enormous impact caused by the orientation of different continents on the spread of food production.

The following figure shows the main orientations of three major continents: Eurasia, Africa, and Americas.

It is obvious that Eurasia is east-west oriented, while Africa and Americas are north-south oriented. The different orientation of continents is the major reason why food production spreaded faster in Eurasia than in Americas and Africa.

In prehistorical times, food production only developed in a few origins, one of which is the Fertile Crescent. Around 8000 B.C., food production arose in the Fertile Crescent. Soon, a centrifugal wave of food production spreaded out, to western Eurasia and North Africa. Diamond draws a map, in which he illustrates the influence of the wave using contour lines.

In the map, food production spreaded much more quickly westwards than northwards. Why?

It is because “localities distributed east and west of each other at the same latitude share exactly the same day length and its seasonal variations. To a lesser degree, they also tend to share similar diseases, regimes of temperature and rainfall, and habitats or biomes (types of vegetation).” (Diamond 176). In addition, there is no insuperable obstacle that obstructs the spread of food production. Therefore, the domesticated crops in the Fertile Crescent could be readily planted in western Eurasia.

In contrast to the east-west axis of Eurasia, the north-south axis of Africa greatly impeded the spread of food production. The 2000 miles of tropical climates in central africa blocked the diffusion, because domesticated crops and livestock couldn’t adapt to the characteristical warm temperature, summer rains, and relatively constant day lengths of low latitudes. 

The same case also applies to Americas. “Most crops and animals failed to spread between Mesoamerica and South America.” (Diamond 180) “The cool highlands of Mexico would have provided ideal conditions for raising llamas, guinea pigs, and potatoes, all domesticated in the cool highlands of the South American Andes. Yet the northward spread of those Andean specialties was stopped completely by the hot intervening lowlands of Central America.” (Diamond 180) Conversely, the possible southward spread of domesticated turkeys and sunflowers of North America was also hindered by the between tropical climates.

                                                              Works Cited

Diamond, Jared. Guns, Germs, and Steel: The Fates of Human Societies. New York: W.W. Norton & Company,Inc., 1999. Print.