THE ANCIENT AGRICULTURAL REVOLUTION
The two most important factors that determine where life is hospitable
to plants and animals, including humans, are geography and climate.
When the Ice Age ended around 10,000 years ago, the last of the glaciers receded and the planet warmed up. This was the first of three major climate changes planet Earth has experienced. the Medieval Warm Period (A.D. 950–1300) followed by the Little Ice Age,
which ended about 100 years ago. Some scientists think that we are in
a new period of global warming caused by pollution from gasses produced by car engines and machinery (the “greenhouse effect”) and that
we have to do something about it fast. Others think it is just part of a
natural cycle. Still others think that climate is random and that a catastrophic change could occur suddenly for no reason and be completely
out of the control of humans.
Humans Learn to Domesticate Foods:
Sheep and Goats, Barley and Wheat
Gathering nuts and seeds and grasses and hunting wild game was unreliable, inefficient, and could support only a limited population. Humans wanted more control over their environment and a guaranteed
supply of food, especially food they liked. So about 10,000 years ago,
humans began to tame wild plants and animals. From the earliest times,
food was bred to taste better, be hardier, and yield more—in other words,
it was genetically modified. This was a time-consuming and difficult
process, because all plants and animals have ways to defend themselves—
husks and tusks, shells and spines. The first domesticated animals were
sheep and goats, then pigs and cows.
After domestication came farming. Fire was a force here, too. Slashand-burn agriculture is one of the oldest and simplest ways to clear the
land of trees. Once used extensively by primitive tribes, it is still used
today in some places, like Borneo. The process: slash the bark on the
tree, which stops the sap from flowing and eventually kills the tree. The
leaves die and fall off, allowing sunlight to filter onto the forest floor
where the fallen leaves decompose into fertilizer. Then crops are planted.
In two or three years, when the soil starts to show signs of being depleted of nutrients, the dead trees are burned, the ash provides fertilizer, and more crops are planted. Unfortunately, this requires constantly
moving into new areas and destroying the forests.
The first cultivated plants were barley, then wheat (Triticum) from
wild grasses. There are about 30,000 varieties of wheat.19 Ancient
wheats—emmer, spelt, einkorn—had several layers of protection, including a very hard inedible outer covering called chaff, which had to
be roasted to be removed. Then friction had to be applied to the wheat
to separate it from the chaff, a process called threshing. This was done
by having oxen walk on the wheat, or by hitting it. The chaff was lighter
than the wheat, so it could be blown or fanned away. Then the wheat
had to be ground to make flour. This was done by hand until animals
began to be used around 800 B.C. These flours were stone ground and
coarse ground, and most likely still contained bits of chaff or fine particles of stone. The problem was that heating the wheat to remove the