All oxygen-dependent life depends on photosynthesis. In addition to breathing the oxygen produced by photosynthesis, humans have been harnessing energy from photosynthesis for millennia. Since the beginning of human societal structures, human needs have driven the evolution of agricultural production, and they continue to do so. Recently, it has been suggested that agriculture can contribute substantially to human technological (nonnutritional) energy needs. This possibility raises concern because the projections of human energy needs argue convincingly that without large increases in energy conversion effciency (ECE), land-grown biofuel production and food production will compete for land, a largely untenable compromise given the current nutritional status of the world's underdeveloped societies.