centuries. In Central Asia, for example, the Kazakhs and Kyrgyz were nomadic pas-
toralists for centuries, but were forced onto collectivized agricultural farms from
1928 to 1933, resulting in massive starvation and incredible losses of animals. Many
herders in these groups simply slaughtered their livestock and left the animals to rot
in the pastures rather than relinquish them to government ownership. Today few
Kazakhs or Kyrgyz are truly pastoral in the way that their ancestors were, although
many still keep some horses, cattle, or sheep. In eastern Africa, the Maasai are a
well-known pastoral group who measure personal wealth by the number of cattle
one possesses. The Maasai diet is also dependent on cattle, as their main source of
protein is the blood of their cattle mixed with milk. The cattle are not slaughtered
when bled; rather the blood is obtained by puncturing the animal’s neck and drain-
ing a small amount of blood, without serious harm to the cow. The Maasai have
retained their traditional lifestyle in spite of efforts by both the Kenyan and Tanza-
nian governments to encourage them to adopt sedentary farming.
Plate Tectonics
Plate tectonics is the notion thatEarth’s crust is composed of a number of huge,
interlocking pieces that slowly move. This knowledge is not abstract nor useless
in that plate tectonics provides us with insight as to why continents and ocean
basins are shaped as they are, why largeearthquakesand volcanoes are focused
in the geographic patterns in which they are observed, and why Earth has its
mountains, folds and faults.
One of the great scientific triumphs of the latter half of the 20th century was the
proof and fleshing out of the implications of plate tectonics. This is a concept so
grand that it was difficult at first for most scientists to believe it. Indeed, some of
the early proponents were ridiculed. Whereas the notion of plate tectonics is a uni-
fying concept, the topic of continental drift is the part of knowledge from which
plate tectonics sprang.
In 1598, the Flemish geographer/cartographer Abraham Ortelius noted the “fit”
between the Atlantic-fringing continents. In 1620, influential Sir Francis Bacon
echoed this as continental coastlines on maps became better defined. Both these
scholars left the subject without proposing a causal mechanism. In 1858, Antonio
Snider-Pelligrini drew “before” and “after” maps of continents and stated that the
continents had moved apart because the biblical flood of Noah restored a lopsided
single-continent Earth to a more even configuration with several continents; this
reasoning became untenable as scientists found increasing evidence that such a
worldwide flood never existed.
Plate Tectonics 255