Biology 11th Edition by Cecie Starr ,Ralph Taggart

تمرين 4

About 50,000 years ago, humans began domesticating wild dogs. By 14,000 years ago, they started to favor new varieties (breeds) by way of artificial selection. Individual dogs having desirable forms of traits were selected from each new litter and, later, encouraged to breed. Those with undesired forms of traits were passed over.
After favoring the pick of the litter for hundreds or thousands of generations, we ended up with sheep-herding border collies, badger-hunting dachshunds, bird-fetching retrievers, and sled-pulling huskies. And at some point we began to delight in the odd, extraordinary dog.
In practically no time at all, evolutionarily speaking, we picked our way through the pool of variant dog alleles and came up with such extreme breeds as Great Danes and chihuahuas.
Sometimes the canine designs have exceeded the limits of biological common sense. How long would a tiny, nearly hairless, nearly defenseless, finicky-eating chihuahua last in the wild Not long. What about English bulldogs, bred for a stubby snout and compressed face Breeders thought these traits would let the dogs get a better grip on the nose of a bull. (Why they wanted dogs to bite bulls is a story in itself.) So now the roof of the bulldog mouth is ridiculously wide and often flabby, so bulldogs have trouble breathing. Sometimes they get so short of breath they pass out.
Why do you suppose many people easily accept that artificial selection practices can produce startling diversity but will not accept that natural selection might do the same in the wild