Conversely, homeostatic organisms are often successful in fine-grained situations, performing well under a broad range of conditions. Regulators are usually intermediate. The concept itself has evolved over the decades, encompassing at least three major ideas. This original concept arose directly from extensive physiological studies, usually in the laboratory, of individual's response curves and especially of their limits of tolerance. This approach assumes that the abiotic environment is the major control of ecological processes, and mainly deals with the properties of individuals.
Resource use leads to the process of ecological competition .
This concept of niche dominated thinking for several decades during which it was accepted that competition for resources was the major ecological interaction among organisms. This concept is mainly concerned with properties of populations. Each individual may play many different roles during its life, and different individuals may play different roles. Some roles may continue for long periods, while others may be limited to rare, brief interludes. Role is the most abstract concept of niche, often difficult to quantify, and usually unsuited to graphical representation.