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No. 20:
Wheat and Farming

Today, we see how a genetic mutation gave birth to our civilization. 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.

To fulfill our destiny as a species of builders and makers, we first had to leave hunting and gathering to take up farming. The scientist and historian Jacob Bronowski tells a remarkable tale of plant genetics that suggests this change came down to a key flash of human ingenuity.

Archaeological evidence makes it clear that two stages of genetic change set the stage. Before 8000 BC, the ancestor of wheat more closely resembled a wild grass than the heavy grain-bearing plant we eat today. Then a mutation occurred in which this plant was crossed with another grass. The result was a fertile hybrid called emmer with edible seeds that blew in the wind and sowed themselves.

The hunting-gathering tribes took to harvesting and eating these seeds. But they didn't have to worry about planting emmer, because it sowed itself.

Then a remarkable thing happened. A second genetic mutation occurred sometime between 8000 and 6000 B.C. This mutation yielded something very close to our modern wheat, with its much plumper grain. It may have happened many times before that, but if it did we'd have no way of knowing, because wheat doesn't blow in the wind, and it can't sow itself. A mutation -- even a fertile one -- couldn't survive on its own.

Modern wheat survives only in a symbiotic relationship with humans. Without someone to harvest it and plant it, it dies away. But somehow some very clever person spotted one of these mutations of emmer and recognized the potential of collecting and manually replanting the seeds. A hunter-gatherer conceived of farming.

This pivotal event in human history happened rather close to the beginning of biblical chronology -- the chronology of humankind once it took up farming. This was the prototypical act of a kind of technological creativity that's gone on ever since. Someone happened across an oddity -- in this case, a stalk of fat grain that couldn't ride the wind -- and saw possibility within it. That person saw how to cast what was evident into a new arrangement and to gain a result that was not evident at all.

I'm John Lienhard, at the University of Houston, where we're interested in the way inventive minds work.

(Theme music)

Bronowski, J., The Harvest of the Seasons. The Ascent of Man. Boston: Little, Brown and Company, 1973, Chapter 2.

I deal with the invention of agriculture in accordance with more up-to-date source material in Episodes 540 and 571.


top: Modern white Gaines wheat.
middle: Emmer
bottom: A wild wheat-like grass, triticum monococcum.