A basic concept of sustainable agriculture includes using resources in a way that does not deplete or permanently damage systems used for plant and animal production. In early history, humans survived as hunter–gatherers and perhaps less than 1% of biomass could be used as food (Diamond, 1997). As a result, most resources in the environment were not likely to be used directly by humans. The limited availability of food also restricted population growth, helping to make the hunter–gatherer way of life sustainable. In contrast, domestication of crops and animals for food has greatly increased edible biomass, leading to dramatic population growth and the possibility that production of adequate food will lead to long-term damage to agricultural systems.

The high productivity of twenty-first-century agriculture is the cumulative result of periods of change called agricultural revolutions. Another revolution based on biotechnology is arguably under way. Some have called the biotechnology-based changes in agriculture the “gene revolution” because they follow the green revolution of the twentieth century, during which high-yielding crop varieties and other changes in production were spread to developing nations. The use of biotechnology in agriculture includes well-publicized techniques such as production of genetically modified (GM; alternatively called transgenic or genetically engineered [GE]) plants and animals, but also less controversial techniques (Herdt, 2006). For example, biotechnology may be used to improve or supplement conventional agricultural methods, such as when marker-assisted selection is employed to enhance traditional breeding of crops.