Organisation at Population Level 33
follow the same path. In the case of its survival, it will be increasing in a
slower rate or will equilibrate in a smaller size.
3.4.2 competition between two Populations
The interaction of (interspecific) competition corresponds to the relationship between two populations that both need to exploit some of the limited
resources present in their environment (space, light, nutrients etc.). The
available resources are not inexhaustible, and sooner or later, a limiting
factor will emerge. The increase of populations intensifies the competition
between them, especially for the resource which is represented by the limiting factor. Each one of the populations attempts to inhibit the other’s
growth and be the only one that will benefit from the available resource.
Exploitation competition arises when the availability of a resource for
each one of the populations is reduced due to the use of the resource by
the other population. Interference competition is manifested by a special behaviour (e.g. territory defence) or by an influence of chemical form
(e.g. through a toxic substance) towards the competitor in order to prevent
his exploitation of the resource. Generally, a necessary precondition for the
existence of competition is an important overlap of the two populations’
ecological niches.
One of the competition’s outcomes is the elimination of the weakest
competitor. The competitive exclusion principle, a significant hypothesis
of theoretical ecology known as Gause’s law, states that when two populations claim the same limited resources, their competition cannot persist
infinitely if the environmental conditions remain stable. One of the two
populations will prove more capable in resource use and will dominate,
whereas the other will perish.
This is a necessary outcome, assuming environmental conditions remain
fixed so that the relative advantage possessed by one of the populations
can last long enough, i.e. until its competitor is eliminated. If environmental conditions are changing so that they benefit both competing species in
turn, it is possible that none of the populations will maintain its advantages long enough to eliminate its competitors; in this case, a permanent
coexistence may result. An essential precondition for the final predominance of one of the competitors is for both species to demonstrate stable
abilities. Competitive species which succeed in evolving so that they achieve
adequate differentiation of ecological niches, may continue to coexist.
Apart from the temporal variability of the environmental factors, coexistence preconditions include spatial variability. In an area of the ecosystem,
one of the competitors might have advantages against the other, causing the
other’s elimination, whereas the opposite can be occurring in a different
area of the ecosystem, whereon it is possible for the competitors to coexist
at the whole ecosystem level. Other potential coexistence factors can be
follow the same path. In the case of its survival, it will be increasing in a
slower rate or will equilibrate in a smaller size.
3.4.2 competition between two Populations
The interaction of (interspecific) competition corresponds to the relationship between two populations that both need to exploit some of the limited
resources present in their environment (space, light, nutrients etc.). The
available resources are not inexhaustible, and sooner or later, a limiting
factor will emerge. The increase of populations intensifies the competition
between them, especially for the resource which is represented by the limiting factor. Each one of the populations attempts to inhibit the other’s
growth and be the only one that will benefit from the available resource.
Exploitation competition arises when the availability of a resource for
each one of the populations is reduced due to the use of the resource by
the other population. Interference competition is manifested by a special behaviour (e.g. territory defence) or by an influence of chemical form
(e.g. through a toxic substance) towards the competitor in order to prevent
his exploitation of the resource. Generally, a necessary precondition for the
existence of competition is an important overlap of the two populations’
ecological niches.
One of the competition’s outcomes is the elimination of the weakest
competitor. The competitive exclusion principle, a significant hypothesis
of theoretical ecology known as Gause’s law, states that when two populations claim the same limited resources, their competition cannot persist
infinitely if the environmental conditions remain stable. One of the two
populations will prove more capable in resource use and will dominate,
whereas the other will perish.
This is a necessary outcome, assuming environmental conditions remain
fixed so that the relative advantage possessed by one of the populations
can last long enough, i.e. until its competitor is eliminated. If environmental conditions are changing so that they benefit both competing species in
turn, it is possible that none of the populations will maintain its advantages long enough to eliminate its competitors; in this case, a permanent
coexistence may result. An essential precondition for the final predominance of one of the competitors is for both species to demonstrate stable
abilities. Competitive species which succeed in evolving so that they achieve
adequate differentiation of ecological niches, may continue to coexist.
Apart from the temporal variability of the environmental factors, coexistence preconditions include spatial variability. In an area of the ecosystem,
one of the competitors might have advantages against the other, causing the
other’s elimination, whereas the opposite can be occurring in a different
area of the ecosystem, whereon it is possible for the competitors to coexist
at the whole ecosystem level. Other potential coexistence factors can be