The Age of Humans The Age of Humans

Six Weird Ways Humans Are Altering the Planet

From deep holes to flying sheep, some signs of human activity might really perplex geologists in the far future

A Burning Man tribute to the last remnants of humanity, a buried Statue of Liberty, depicted in the 1967 science fiction film, Planet of the Apes. (Courtesy of Flickr user Brian J. Matis)

Fat Turkeys, Sweet Corn

(Wikimedia Commons)

Humans have been cultivating and domesticating plants and animals since the dawn of agriculture, around 10,000 B.C.E. And people have been cross-breeding different species and cultivars to artificially select for specific traits for almost as long. Take the turkey: Thanks to changes in diet, vaccines and artificial insemination, breeders have created a much larger bird than its wild relative. Today’s commercial turkeys are more energy efficient when it comes to converting feed to body weight, giving them much larger chest muscles. However, these birds have trouble walking, can’t fly and are no good at regulating their food intake.

Crops are also drastically different from their wild counterparts. Corn grown today is significantly sweeter than maize consumed a few centuries ago. A genetic mutation that replaces some of the grain’s starch with sugar gave us sweet corn, which was grown by the Iroquois and passed on to European settlers in 1779. Subsequent revelations about corn genetics have allowed farmers to breed even sweeter varieties. The opposite is true of potatoes, which have been bred to be starchier for better cooking and frying.

Then there are crops and a handful of animals that have undergone genetic engineering, including Rainbow papayas made resistant to viruses and soybeans that can tolerate herbicides and pesticides. Though precautions are taken to prevent these genetic variants from drifting into wild ecosystems, it’s unclear how modified plants might fare if left unchecked. And engineered or otherwise, crops have lost an estimated 75 percent of their genetic diversity over the last century, which makes it harder for staple breeds and cultivars to adapt to environmental change, drought or disease. 

About Helen Thompson
Helen Thompson

Helen Thompson writes about science and culture for Smithsonian. She's previously written for NPR, National Geographic News, Nature and others.

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