Cheers to Katharine Milton (“Something to Howl About,” 10/03) for illuminating the importance of two critical facts about population ecology — that “prudent” parasites do not kill their hosts, and that population size fluctuates in response to the availability of food.

Jeers to Marc J. Cohen (“Crop Circles”, 10/03) and Laurence A. Marschall (Review, “Space, the Final Frontier?”, 10/03), who, in the very same issue as Milton’s piece, both overlook those important ideas and whose book reviews suffer as a result. Had they been aware of these ecological facts, surely they would have cut to the chase on their respective topics:

GM food may remain ethically ambiguous, but the simple fact is that, GM or organic or anywhere in between, it is the very act of increasing the volume of food production that increases the human population. Combined with the inegalitarian social structures that pervade our global society (and that are themselves related in part to population growth), this ensures that hunger will continue. GM food may not be the ultimate evil some make it out to be, but it can never solve hunger.

Technology for space travel may evolve, but, even if perfected, the simple fact is that colonizing space would require people en route to live in ecological balance within their spacecraft. If such knowledge were available, then it could instead be applied on Earth itself. Thus, space would not need to be used as a “safety valve for a planet threatened by pollution and overpopulation” — and thus the trip would not be necessary.