Analyzing the implications of evolutionary tradeoffs, Denison argues in Darwinian Agriculture that biotechnology and breeding efforts should sometimes reverse the results of past evolution that are inconsistent with present goals. For example, the ratio of photosynthesis to water use is greater for a plant in the morning when humidity is higher; it would therefore sometimes be better for crop yield if plants simply shut down in the afternoon. Why then, Denison asks, have plants not naturally evolved to do so? The answer, he states, is competition among plants: if one plant sacrifices its water intake for an afternoon, a neighboring plant will use water saved by the former. As a result, past natural selection favored individual growth at the expense of the plant community.
"Drought resistance is great when needing to get through a week without rain," Denison says. "In agriculture, however, simply surviving is not enough – a crop actually needs to produce a grain or fruit. What we need is a plant able to produce more with a given amount of water. This is much more difficult, but that also means there may be more opportunity for us to improve on what evolved naturally."