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Evolution does not design from scratch; it modifies parts that already exist. That is why living bodies can look clever and improvised at once. Feathers, for example, appeared in dinosaurs long before any of them could fly, probably for warmth and display.

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The French biologist François Jacob, a Nobel laureate, made the point famous in a 1977 essay in the journal Science called “Evolution and Tinkering”. Natural selection, he argued, works less like an engineer with a fresh plan and more like a tinkerer who makes do with whatever is at hand. Biologists call a trait that is reused for a new job an exaptation, a term coined by Stephen Jay Gould and Elisabeth Vrba in 1982. The same history leaves awkward leftovers. In mammals, a nerve to the voice box runs down into the chest, loops around a major blood vessel and climbs back up to the throat. The route was inherited from fish-like ancestors, in which the nerve ran straight past the heart to the gills. In a giraffe the detour is estimated at about 4.6 metres.

Türkçe oku
Evrim hiçbir şeyi sıfırdan tasarlamaz; zaten var olan parçaları değiştirerek ilerler. Canlıların hem ustaca hem de biraz derme çatma görünmesi bu yüzdendir. Örneğin tüyler, dinozorlarda uçuştan çok önce, büyük olasılıkla ısınmak ve gösteriş için ortaya çıktı.

Bu fikri Nobel ödüllü Fransız biyolog François Jacob, 1977'de Science dergisinde yayımladığı “Evolution and Tinkering” (Evrim ve Tamircilik) başlıklı yazısıyla ünlü kıldı. Jacob'a göre doğal seçilim, önünde tertemiz bir proje bulunan bir mühendis gibi değil, elinin altındakiyle idare eden bir tamirci gibi çalışır. Biyologlar, yeni bir işe koşulan eski bir özelliğe eksaptasyon der; terimi 1982'de Stephen Jay Gould ve Elisabeth Vrba önerdi. Bu geçmiş, geride tuhaf izler de bırakır. Memelilerde gırtlağa giden sinirlerden biri önce göğse iner, büyük bir damarın çevresinden dolanır ve yeniden boğaza çıkar. Bu yol, sinirin kalbin yanından geçip doğrudan solungaçlara gittiği balık benzeri atalardan kalmadır. Zürafada bu dolambaçlı yolun yaklaşık 4,6 metreyi bulduğu hesaplanıyor.

Sources and further reading

Background reading: Evolution
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The historian E. P. Thompson traced this change in a famous essay of 1967, “Time, Work-Discipline, and Industrial Capitalism”. Farm and craft work, he argued, had been measured by tasks: milking, harvesting, finishing a piece. Factory work was measured in hours. Cromford Mill, opened in 1771, was the world's first water-powered cotton-spinning mill. It started with about 200 workers, most of them women and children, the youngest only seven. Bells rang at 5 in the morning and 5 in the evening, the gates were shut at exactly 6, and anyone late lost that day's pay and was fined another. In industrial towns, where alarm clocks were not yet cheap or reliable, “knocker-ups” were paid a few pence a week to tap on upstairs windows with long poles.

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Less than 66 years, well within a single lifetime, separate the first powered aeroplane flight from the first Moon landing. Orville Wright flew for 12 seconds and 37 metres on 17 December 1903; Apollo 11 landed on the Moon on 20 July 1969.

The Wright brothers, bicycle makers from Dayton, Ohio, flew near Kitty Hawk, North Carolina, and that first hop was shorter than the wingspan of a Boeing 747. What followed came fast. In 1919 John Alcock and Arthur Brown flew non-stop across the Atlantic; in 1927 Charles Lindbergh did it alone, from New York to Paris; and in 1947 Chuck Yeager flew faster than sound. Orville Wright died in 1948, nine years before the Soviet satellite Sputnik opened the space age. Yuri Gagarin orbited the Earth in 1961, and in July 1969 Neil Armstrong took a scrap of the 1903 Flyer's wood and fabric with him to the Moon.

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The Cold War between the United States and the Soviet Union (1947–1991) was fought mostly without direct battles between the two. They competed instead through weapons, science, sport, films, propaganda and the race into space.

George Orwell used the phrase “cold war” in 1945, and the American journalist Walter Lippmann made it popular in 1947. Because nuclear weapons made open war between the superpowers too dangerous, the rivalry spread into other arenas. After the Soviet Union launched the Sputnik satellite in 1957, the United States passed the National Defense Education Act of 1958 to fund science, maths and language teaching. In 1959, at an American exhibition in Moscow, Vice-President Richard Nixon and the Soviet leader Nikita Khrushchev argued about capitalism and communism in a model kitchen, an exchange remembered as the Kitchen Debate. In 1972 in Reykjavík, the American Bobby Fischer beat the Soviet champion Boris Spassky for the world chess title. The Olympics were boycotted in turn: the United States and many allies stayed away from Moscow in 1980, and most of the Soviet bloc from Los Angeles in 1984.

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