Week 5: Ecological niche and keystone species Flashcards
ecological niche
The way a population of organisms functions in an ecosystem
A niche can be described in terms of the population’s:
Habitat
The roles the organisms in the population play in the habitat
Feeding relationships
Interactions with other species.
If zone of overlap in a niche overlap graph is small, there is
little competition between species
When do niches overlap?
when two species compete for same resources. This is referred to as interspecies competition.
When two organisms compete for same resources the niche of the
more successful competitor will increase
less successful competitor will decrease.
if two species occupy the same niche, one will outcompete the other resulting in one species
disappearing from ecosystem
The amount of an ecological niche that is occupied by one species is dependent on
the competition from other species.
Fundamental niche
the set of conditions under which an animal (population, species) can survive and reproduce itself with absence of competition.
Realised niche
set of conditions actually used by given animal (pop, species) and their actual role in community after interactions with other species (predation and especially competition) have been taken into account.
Stable ecosystems
Ecosystems that are maintained over long periods of time and are able to meet the requirements of all niches
Ecosystems will persist only if they can
transfer, capture and transform energy + cycle essential nutrients and chemical elements effectively
keystone is the
most important stone of arch. Ensures it’s stability is maintained
How many keystone species does an ecosystem have at least?
1
Other species in ecosystem can’t survive without the
keystone species as habitat is changed dramatically with it’s removal
removal or extinction of keystone species cause a
trophic cascade
