Geoscience Reference
In-Depth Information
Figure 17.4. Short-horned Neolithic cow skeleton (
Bos brachyceros
), Adrar Bous,
south-central Sahara.
meat for sustenance and wool and hides for shelter and clothing. A diet of cereal
porridge and milk is easier for infants to digest than their probable pre-Neolithic
diet, so infant mortality rates decreased and birth rates increased. The Y chromosome
genetic evidence shows an expansion of East Asian Mongoloid groups around 7 ka,
perhaps as a result of millet and rice farming, a situation matched in the Near East
after farming arose there (Underhill et al.,
2001
). More than thirty years ago, May
(
1978
) estimated that the world population at the start of the Neolithic some 10,000
years ago amounted to little more than about 5 million, increasing to 100 million by
5 ka, and thereafter increasing ever faster to around 500 million by 300 years ago, 1
billion (1
10
9
) by 1850, 4 billion by 1978, and more than 7 billion by 2012. With
more people came an ever greater and often adverse impact on ecosystems, including
soils and water (Diamond,
2005
), as well as increasing pollution of land, air and water,
topics we discuss in Chapters
24
to
26
.
Another feature of Neolithic life was also to have lasting repercussions. With the
ability to obtain and store a substantial food surplus, there was a progressive change
from nomadic herding to sedentary farming, with the growth of villages and, ulti-
mately, major urban centres in well-watered river valleys or upland sites with reliable
supplies of water. Trade proliferated, as did the emergence of social hierarchies, with
a small, powerful and wealthy ruling class, supported by artisans, priests and soldiers.
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