Today, a new look at the birth of a very old technology. The University of Houston's College of Engineering presents this series about the machines that make our civilization run, and the people whose ingenuity created them.
Scholars have been turning their lenses back on the invention of farming. We know farming began eight to ten thousand years ago in the Middle East and the Holy Land. We also know it began after certain wild wheats mutated.
The seeds of those wild grains weren't as fat and rich as modern wheat, but they blew in the wind. They sowed themselves. You could harvest them without having to plant them.
Modern wheat was a fertile mutation of wild wheat. It made much better food. But its seeds don't go anywhere. They're bound more firmly to the stalk, and they cannot ride the wind. Without farmers to collect and sow wheat, it dies. Modern wheat creates farming by wedding its own survival to that of the farmer.
In 8000 B.C. the Natufians -- a hunting-gathering people -- lived in the region around Jericho and the Dead Sea. They were first to cultivate this new mutation -- this modern wheat. They became the first farmers.
By then, the climate had been warming for 2000 years. Once the area had been fairly lush. Now it grew arid. Game moved north. The vegetation changed. But the wild grains did well in the drier climate. The Natufians began eating a lot more grain.
And here we come to a great riddle. How did modern wheat replace those wild grains? Isolated mutations died without human help. Was some human clever enough to recognize and pick out that lone stalk of fat wheat in a field of grain?
We used to think so. But maybe the drama played out in quite a different way. By 8000 B.C. the Natufians needed much more grain. They probably began doing some planting to create it. Once they did, the fat wheat had its chance. It was easier to harvest. The seeds stayed in place when you cut it. Every time the Natufians harvested seed, they got proportionately more of the mutations. They lost more of the wild grain.
It took only a generation or so of that before a single mutation took over. The result was an unexpected wedding. In no time at all, modern wheat dominated the fields. And that was both a blessing and a curse.
The Natufians unwittingly replaced the old wild wheat with far richer food. But it was a food that could survive only by their continued intervention. No more lilies of the field. From now on we would live better, but we would also be forever bound to this wonderful new food by the new technology of agriculture.
I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.
Stevens, W., Dry Climate May Have Forced Invention of Agriculture. New York Times, SCIENCE, Tuesday, April 2, 1991, Section B.
Toward the beginning of this series, I did an episode on wheat and the invention of farming (Episode 20). In it I suggested that recognizing the modern wheat mutation, and replanting it, was a stroke of ingenuity. The case presented here stems from recent work by Frank Hole and Joy McCorriston of Yale University. If it's correct, then the act of ingenuity occured when Natufians realized they could replant wild wheat. They probably didn't know they were reinforcing a new species.
top: Modern white Gaines wheat.
bottom: A wild wheat-like grass, triticum monococcum.