Read Online 7 Billion by National Geographic - Free Book Online Page B

wheat, for example, drops its ripened kernels to the ground, or shatters, so that the plant can reseed itself. Early farmers selected out wheat that, due to a random genetic mutation, didn’t shatter and was thus ideal for harvesting.
    Farmers and breeders painstakingly developed livestock breeds and food crops well suited to the peculiarities of their local climate and environment. Each domesticated seed or breed was an answer to some very specific problem—such as drought or disease—in a very specific place. The North American Gulf Coast Native sheep, for example, thrives in high heat and humidity and has broad parasite resistance. On the remote Orkney Islands, North Ronaldsay sheep can live on nothing but seaweed. Zebu cattle are more resistant to ticks than other cattle. In Ethiopia a small, humpless, short-horned cattle breed called the Sheko is a good milk producer that withstands harsh conditions and has resistance to sleeping sickness.
    Such adaptive traits are invaluable not only to local farmers but also to commercial breeders elsewhere in the world. Finnsheep, for example, long raised only by a small group of Finnish peasants, have become vital to the sheep industry because of their ability to produce large litters. The Fayoumi chicken, an indigenous Egyptian species dating back to the reign of the pharaohs, is in great demand as a prodigious egg layer with high heat tolerance and resistance to numerous diseases. Similarly, the rare Taihu pig of China is coveted by the world’s pig breeders for its ability to thrive on cheap forage foods and its unusual fertility, regularly producing litters of 16 piglets as opposed to an average of 10 for Western breeds.
    The irony is that the dangerous dwindling of diversity in our food supply is the unanticipated result of an agricultural triumph. The story is well-known. A 30-year-old plant pathologist named Norman Borlaug traveled to Mexico in 1944 to help fight a stem rust epidemic that had caused widespread famine. Crossing different wheat varieties from all over the world, he arrived at a rust-resistant, high-yield hybrid that helped India and Pakistan nearly double their wheat production—and saved a billion people from starvation. This so-called green revolution helped introduce modern industrialized agriculture to the developing world.
    But the green revolution was a mixed blessing. Over time farmers came to rely heavily on broadly adapted, high-yield crops to the exclusion of varieties adapted to local conditions. Monocropping vast fields with the same genetically uniform seeds helps boost yield and meet immediate hunger needs. Yet high-yield varieties are also genetically weaker crops that require expensive chemical fertilizers and toxic pesticides.
    The same holds true for high-yield livestock breeds, which often require expensive feed and medicinal care to survive in foreign climates. The drive to increase production is pushing out local varieties, diluting livestock’s genetic diversity in the process. As a result, the world’s food supply has become largely dependent on a shrinking list of breeds designed for maximum yield: the Rhode Island Red chicken, the Large White pig, the Holstein cow. In short, in our focus on increasing the amount of food we produce today, we have accidentally put ourselves at risk for food shortages in the future.
    One cautionary tale about the perils of relying on a homogenous food source revolves around the humble potato. High in the Peruvian Andes, where the potato was first domesticated, farmers still grow thousands of otherworldly looking varieties. Spanish ships in the late 16th century first brought the tuber to Europe, where by the early 1800s it had become a reliable backup to cereal crops, particularly in the cold, rain-soaked soils of Ireland. The Irish were soon almost wholly dependent on the potato as their food staple. And they were planting primarily one prodigious variety, the Lumper potato,