See what scientists believe about humans' artificial selection pressures on the dog ... In fact, the variation among breeds of dogs is far greater than the variation among other completely ...

The study found that dog breeds with larger relative brain ... They are a function of artificial selection... a very directed selection, evolution under human hands," Balcarcel said.

A dog breeder explains selective breeding, looking at puppies that have useful and less useful traits. Michaela explains how artificial selection is also used in vegetables, showing how broccoli ...