competition Flashcards
define competition
an interaction between individuals brought about by the sharing of a resource leading to a reduction in survivorship, growth and reproductioon
define intraspecific competition
the combined demand for a resource exceeding immediate supply from individuals in the same species
how can intraspecific competition cause decreased populations
increased energy spent to locate food, as well as reduced food intake means there is reduced contribution to the next generation
what the different modes of competition
1) exploitation - where an individual of as species reduces amount of resources for other individuals
2) interference - more of a direct competition where individuals prevent another from exploiting a resource
why does a population not increase as a result of competition
they face comp for resources, exploitation and interference decrease survivorship preventing increased growth
what determines the intensity of intraspecific competition
1) the density of a population
2) the extent of crowding in an immediate area = unequal distribution of resoruces in less dense
what is the law of constant final yield
when density is very high and resources are limited the effects of competition result in a constant biomass between individuals due to proportional decreases in the size of individuals
- there are more individuals, however they are all smaller
what is territoriality
the active interference (directly preventing access to resources) between individuals to depend an exclusive area against intruders using a pattern of behaviour
how is terriroriality a cost benefit stratergy
the defence of a resource must be offset against the benefit of the occupation of the area
e.g. may involve combat and energy to maintain so benefits must exceed the costs to be favoured by natural selection
define interspecific compeitition
where one individuals of a species deprives another of a different species from a vital resource leading to slower growth and greater risk of death
what are some resources which can be consumed or depleted causing competition
- food
- water
- light or nurtients for plants
- PH
define exploitation competition
species compete indirectly through mutual effects on availability of a shared resource
what is interference competition
species compete direclty for access to a resource such as combat or territioariality
how does the acorn barnacle demonstrate intereference competition
crushes or smothers nearby individuals of another barnacle species as it grows, preventing the other species from living there
define allelopathy
a form of interference competition in which individuals of one species release toxins that harm another species
how does knapweed demonstrate allelopathy
releases a toxin called catechin into soils reducing germination of native grasses
what is the competitive exclusion principle
when two species use a limting resource in the same way, they can not coexist and one is driven to extinction
what is resource partioning
when species use a limtied resource in a different way
what is competitive reversal
where the species which was the inferior competitior in one habitat becomes the superior in another as a result of a change in environmental conditions
what is character displacement
where natural selection can influenced the morphology of a competing species resulting in the species becoming more different over time
