Crops

Human beings can only be sustained by utilizing other species as sources of food, material, and energy. Humans have thus always had an absolute requirement for the goods and services provided by other species, and this will always be the case. Although direct genetic modification has in the last few years been added (controversially) to artificial selection as a technique for adjusting plant and animal species to our needs, there is no prospect of a time when technology will make it possible to meet our needs by applying energy directly to raw materials. Humans have always needed and always will need to harvest other living things.

Prior to the discovery of the first agricultural techniques about 9,000–11,000 years ago, almost all human societies were sustained by gathering edible or otherwise useful products of wild plants, and by hunting wild animals. The plant foods that were gathered as crops by these early peoples included starchy tubers, fruits, and seeds. Other plants were harvested as sources of fuel or to provide materials such as wood and bark for the construction of shelters, canoes, and other tools or weapons. Animals, meanwhile, were hunted for their meat, hide, and bones. Prior to the development of agriculture—the breeding and deliberate nurturing of useful plants and animals—these activities were undertaken in essentially natural ecosystems—ecosystems not intensively modified by the hunting and gathering activities of people.

Humans have been rather eclectic in their choice of crops, selecting a wide range of useful species of plants, animals, and microorganisms from among the vast diversity of species available in most places or regions. Humans are considered omnivorous, because they feed at all levels of ecological food webs: on plants, animals, and other types of organisms, both living and dead.

Human societies that subsist only by the hunting and gathering of wild crops are now virtually extinct. However, modern human societies continue to obtain important plant and animal crops from essentially unmanaged ecosystems.