Why study competition? All life forms consume resources such as water, oxygen, and nitrogen. This consumption reduces the supplies available for neighbours. In order to maintain access to resources, organisms sometimes must interfere with their neighbours. These three sentences summarize the state of affairs of both the simplest bacterium and the most self-assured twentieth century human. Without resources, organisms will die, and so the contest to find, harvest, transport, store and retain possession of resources is an essential part of the struggle for survival.