Within fifty to a hundred years, a new call of organisms is likely to emerge. These organisms will be artificial in the sense that they will originally be designed by humans. However, they will reproduce, and will evolve into something other then their initial form; they will be "alive" under any reasonable definition of the word. These organisms will evolve in a fundamentally different manner than contemporary biological organisms, since their reproduction will be under at least partial conscious control, giving it a Lamarckian component. The pace of evolutionary change consequently will be extremely rapid. The advent of artificial life will be the most significant historical event since the emergence of human beings. The impact on humanity and the biosphere could be enormous, larger than the industrial revolution, nuclear weapons, or environmental pollution. We must take steps now to shape the emergence of artificial organisms; they have potential to be either the ugliest terrestrial disaster, or the most beautiful creation of humanity.
Farmer, J.D. & Belin, A.d’A. (1991). 'Artificial Life: The Coming Evolution.' In Langton, C.G., Taylor, C., Farmer, J.D. & Rasmussen, S. (Eds.) "Artificial Life II". Reading, CA: Addison-Wesley. pp.815-840.