SECTION 17.2
Competition in Communities
Competition
◦When 2 species use the same resource =
competition
◦Examples: food, nesting sites, water, light,
soil minerals
◦The resources an organism needs are its
niche
Niches
◦Fundamental niche – all the resources in
the ecosystem that the animal could use
◦All of this niche can’t be used because of
competition with other species
◦Realized niche – the resources that the
animal actually uses
How animals deal with competition
◦Competitive exclusion – 2 species can’t use
the same resource at the same time
◦One animal ‘wins’ and the other animal
‘loses’
◦Usually not a fight to the death
◦One animal just moves to a different
location
How animals deal with
competition…
◦Resource partitioning – a way to reduce
competition
◦When 2 animals are trying to use the same
limited resource, they may divide it
between themselves
◦Example: hawks hunt during the day and
owls at night
Predation and competition
◦Predators keep the prey population under
control
◦Without this control the competition for
resources can increase
◦More competition can cause less
biodiversity as weaker species are
eliminated