A Moment of Science

How Did Corn Evolve?

Have you ever wondered how corn evolved? Learn how early humans cultivated the corn we have today.

Corn field on a summer day

Photo: Stock Exchange

Corn was selectively bred by humans starting ten thousand years ago to create what it is today

Have you ever wondered how corn evolved? After all, the seeds are all crammed together on the cob and wrapped tightly inside the thick husks. Seems impossible for the seeds to disperse without a human to peel the husks and separate the kernels.

Come to find out, corn, or maize, only exists in its modern form because of humans. Evidence from archaeological and genetic studies suggests that maize was bred and cultivated by early inhabitants of Mexico as early as ten thousand years ago. The early Mesoamericans managed to develop corn from its grassy ancestor by selective breeding. Maize was bred from a wild grain called teosinte.

Teosinte is so unlike modern corn that originally botanists didn’t think the two were even related. An ear of teosinte is only about three inches long, with just five to twelve kernels. Compare that to the corn we eat today, which can have over five-hundred kernels!

Teosinte kernels also have a “tooth-crackingly” hard shell. But through many generations, ancient Americans selectively bred plants with larger and larger ears, and softer and softer kernels. Now all that is left of that hard shell is the thin tissue that gets stuck between your teeth when munching a cob of corn.

Lets tip our hats to the ancient Mesoamericans! Thanks to their sophisticated understanding of plant breeding, we have corn for eating, livestock feed, cooking oil, ethanol and even making plastics!

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