Allright, you probably thought I was going to announce I was a creationist or something. No I just wanted to show a few cases where evolution created bizzarre effects. For years farmers bred their livestock for the most productive ones, and with chickens it was usually for egg laying. They would select for the hens that layed to most eggs. Now, years later, the desendents of chickens from these breeding programs have to have their beaks clipped and housed in seperate cages. The reason is because the chickens that layed the most eggs also happened to be more aggressive and fight their way to the top of the pecking order. A researcher tried a new approach to selective breeding on these chickens. By using group selection, after only six generations he had increased the productivity of the birds by more then double and increased the life expectancy by nearly 3 times. (
source.)
Once, a swedish researcher tried to increase wheat yields and picked the biggest wheat kernels to plant each year. After only 5 generations he had a strain of wheat that produced 6 giant wheat kernels per stalk.
When insects were damaging fruit trees, farmers expirimented with using cyanide to poison them. They put up giant tents over the whole trees and pumped in cyanide, killing the insects. Plants are immune to cyanide but no animal that uses respiration can be. And in only 5 years or so they had resistant insects. The resistant insects would -- when anything startling happen -- sit very still and hold their breath for half an hour or so.