NICHE

=Ecological Niche= The functional position of an organism within it's ecosystem [image:http://i.imgur.com/dfdWjqE.png?1] Niche is a complex term that has itself evolved over time. An organisms niche is where it best fits into an ecosystem. If you can think of an organisms habitat as its address, then it's niche could be describe as its "profession". Niche is a combination of where an organisms lives (its habitat), how it make a living there (adaptations) and the role it performs in the community. It includes the sum total of an organisms requirements; it's way of life. When describing an organisms niche, you should try to include... *Its '''habitat''' (abiotic and biotic factors, including any if it's requirements) *Its '''adaptations''' (any structural, physiological or behavioural traits that enable to survive in its habitat) *Its '''role''' (e.g. producer, how it fits into a food web or interacts with other species) ==Gause's Principal of Competitive Exclusion== No two species can occupy the same ecological niche; eventually one will out-compete the other If two species are in direct competition for the same resources one will eventually out-compete the other. This occurs because if one of the two species has even the slightest advantage or edge over another then it will be able to produce more offspring in the run. Because it's descendants will be more numerous they will consume an even greater share of the resource. As a result the other species will go extinct or is forced to find an alternative way of making a living; an alternative niche. The niche width of an organism refers to a theoretical range of conditions that a species could inhabit and successfully survive and reproduce with no competition. The niche width is defined as the parameters of this range which are determined by biotic and abiotic factors such as suitable climate and appropriate food sources. ==Realised Niche== [image:http://i.imgur.com/m3EO3Bu.png?1] An organism's '''fundamental niche''' is the full range a species can occupy without interference from other species. However, inter-specific '''competition''' often forces species to occupy a much narrower niche, to which they are mostly highly adapted. This is termed the realized niche. For instance, ''Chthamalus'' (a type of barnacle) is generally only found in the high tide zone -where it is best adapted to survival / most competitive. This is its realised niche. However, if a neighbouring type of barnacle (''Balanus'') is removed ''Chthamalus'' can actually occupy the entire intertidal zone -its fundamental niche. [image:http://i.imgur.com/fBiliB6.png?1] Where the niche of two species overlaps competition occurs. Ultimately one or both species will be forced into a narrow, realised niche. As a result their distribution / range (the width of the bell curve) becomes narrower.