Since the word biodiversity metamorphosized from a term of scientific discourse to a popular code word for environmental crisis, it has also come to be equated with the tropical rainforest, earth's great engine of species creation. While less diverse (and less studied), the world's drylands contain significant numbers of species, including several of the largest land animals on the planet. Humanity itself is a product of the drylands, as are many of the things we eat. Of most immediate interest are the genetic reservoirs of crucial staple crops such as maize, wheat, and barley, upon which a good portion of earth's 6 billion people depend for sustenance. Within various land races of these staple crops are adaptations to disease and drought that will prove vital as threats to wheat, corn and other endemic dryland crops emerge. If overall dryland species diversity is not as great as the rainforest, within species diversity is far greater as flora and fauna adapt to widely diverse dryland habitats with steep ecological gradients. The genes of species in very arid lands contain myriad ingenious adaptations to harsh conditions ranging from water deprivation to extreme heat, which may prove increasingly important should climate continue to warm.