Apart from population pressure being a possible catalyst, resources
they had been depending on suddenly become scarce. This is
probably the initial catalyst. It may seem odd, but in those hunting
and gathering days, the Earth was also in the tail end of the last
major ice age, which meant that humans were relatively confi ned to
the warmer parts of the Earth and closer to the tropics, but so were
the animals they hunted and the plants they depended on. When the Earth began to get warmer—from about 60 degrees
in summer to about 80 or more—there was more food and more
fi elds. What used to be great frozen glaciers became lush prairies.
The animal populations were no longer contained. Because the
vegetation grew more easily, the gathering was much better for
humans, too, so their populations also grow. However, suddenly, they are out of balance. Hunting is harder, and
gathering is easier. More mouths to feed means greater pressure
to increase yield. Historians guess that plants were domesticated,
which means to actively change a species to accentuate certain
desired traits until that species no longer resembles the plant that
grew in the wild. Dogs were probably the fi rst animals to be domesticated, by
accident, following around human camps for scraps and providing
some watch from other predators. Not only can these animals
be trained to stay in herds, but they also are ruminants, which is
important because they can be fed grass (which humans can’t eat)
instead of other animals.The Spread of the Agricultural Revolution
About 10,000 years ago, the fi rst place the agricultural revolution hit
was the region called the Fertile Crescent, an arc covering what is
today Iraq, Syria, eastern Turkey, Lebanon, and Israel. This region
just happened to luck out by having a lot of easily domesticated
plants and animals, including goats, sheep, and cows, which offer
meat, wool, hides, milk, and cheese. These types of animals provide
insurance, traction, transport, and manure (fertilizer).