Background
Two ecological paradigms deal with the problem. The first paradigm predominates in what may be called “classical” ecology. It assumes that niche space is largely saturated with individuals and species, leading to strong competition. Niches are restricted because “neighbouring” species, i.e., species with similar ecological characteristics such as similar habitats or food preferences, prevent expansion into other niches or even narrow niches down. This continual struggle for existence is an important assumption of natural selection introduced by Darwin as an explanation for evolution.
The other paradigm assumes that niche space is to a large degree vacant, i.e., that there are many vacant niches. It is based on many empirical studies and theoretical investigations especially of Kauffman 1993. Causes of vacant niches may be evolutionary contingencies or brief or long-lasting environmental disturbances.
Both paradigms agree that species are never “universal” in the sense that they occupy all possible niches; they are always specialized, although the degree of specialization varies. For example, there is no universal parasite which infects all host species and microhabitats within or on them. However, the degree of host specificity varies strongly. Thus, Toxoplasma (Protista) infects numerous vertebrates including man, Enterobius vermicularis infects only man.
The following mechanisms for niche restriction and segregation have been proposed:
Read more about this topic: Niche Segregation
Famous quotes containing the word background:
“In the true sense one’s native land, with its background of tradition, early impressions, reminiscences and other things dear to one, is not enough to make sensitive human beings feel at home.”
—Emma Goldman (1869–1940)
“Pilate with his question “What is truth?” is gladly trotted out these days as an advocate of Christ, so as to arouse the suspicion that everything known and knowable is an illusion and to erect the cross upon that gruesome background of the impossibility of knowledge.”
—Friedrich Nietzsche (1844–1900)
“... every experience in life enriches one’s background and should teach valuable lessons.”
—Mary Barnett Gilson (1877–?)