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ANTARCTICA i

Figure 14.2 Regions of domestication of some crop plants. Data from Jack R. Harlan. Crops and Management, 2nd edition. Am. Soc. Agronomy.

We do not know why most humans shifted from a hunter-gatherer lifestyle to an agricultural one. Several hypotheses exist, but they are purely speculative. Hunter-gatherers seemed to live better lives than cultivators did. Their diet and health were better, their starvation rate was lower, and they worked far fewer hours. Their work week was only about 20 hours long! Because they had abundant free time, hunter-gatherers may have simply begun to grow plants in gardens as a hobby. They may have begun to cultivate a few plants to supplement lean times in the gathering schedule. Or, they may have had spiritual reasons for growing plants in a protected environment. Because agricultural practices arose independently in many parts of the world over thousands of years, each of these scenarios probably explains why humans began to domesticate plants.

People began to domesticate plants in the Near East around 10,000 years ago. Many agricultural sites from this time period have been located on the western edge of what is now Iran. Domesticated plants were developed in Asia 1,000 to 2,000 years later. Farming probably began in Africa and the New World about 4,000 years ago.

The first crops domesticated were cereal grains. Root crops and legumes, such as peas and beans, were domesticated 1,000 to 2,000 years later. These were followed by vegetables, and then oil, fiber, and fruit crops. Finally, plants used for forage, decoration, and drugs were first domesticated only about 2,000 years ago. Few crops have been brought into domestication in recent centuries. Plant breeders currently devote much more energy to improving existing crops than developing new ones. The map in Figure 14.2 shows where some of our major crops were domesticated. Sunflower is the only major crop that was domesticated in the present day United States (Fig. 14.3).

John Doebley
Figure 14.3 The sunflower is the only major crop that was domesticated in the United States.

Chapter 14

Modern Plants Steps

Figure 14.4 Modern corn (left) was probably domesticated from teosinte (right). Teosintephoto courtesy John Doebley.

Figure 14.4 Modern corn (left) was probably domesticated from teosinte (right). Teosintephoto courtesy John Doebley.

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