In the previous chapter, it was argued that manipulation or exploitation of the environment is a widespread evolutionary strategy. It also tried to show why this should be so. Dealing with the environment as a resource, as something to be manipulated and exploited in the accomplishment of one's day to day tasks, is not an optional extra: for most creatures it is a basic biological necessity. Since evolutionary strategies that involve manipulation or exploitation of environmental structures can, in general, be adopted at less evolutionary cost than strategies that do not, any organism that adopts a non-manipulative strategy in the performance of a given task is, at least with respect to that task, differentially less fit than an organism that adopts a manipulative one. The former creature, then, risks being outcompeted for the possession of any jointly coveted environmental niche. Evolutionary constraints, therefore, mean that for most creatures, if not all, the environment must be dealt with as a resource.