National Geographic had a great article on the decreasing diversity of seeds and animals that have been feeding us for centuries. Previously, we only grew seeds that had been proven to grow to our specific region. Years, sometimes decades or more, were spent by farmers discovering which seeds could handle the local climate, diseases and other various issues unique to where they grew. But in the forties came the Green Revolution.
Black Silkie ChickenStem rust was slowly ravaging the wheat supply causing terrible famine in the developing world and threatening to spread to the first world. Norman Borlaug was able to cross several wheat varieties to create a new variety resistent to stem rust. This "green revolution" helped bring modern industrialized agriculture to the developing world. Unfortunately, this has led to many farmers becoming dependant on high-yield crops broadly adapted to a wider market rather than the unique environments they grow in. Stem rust has now made a come back in the form of Ug99 (for Uganda where it was discovered in 1999). With monocropping, the world's wheat supply is now in danger.
Texas Mountain Laurel
Check out the article Food Ark by Charles Siebert at the National Geographic website to learn more about what is happening to the vast diversity that once existed in our food supply.