EE Lecture 21: Niches Flashcards
define niche
the ecological role of a species - the set of constraints on pop growth
what are the consequences of niches
character displacement/competitive exclustion
adaptive radiation/extinction
inc biodiv or dec biodive
what is the competitive exclusion principle (Gause’s Principle)
species with similar niches cant coexist in eqbm
which principle states that species with similar niches cant coexist in eqbm
Gauses compeititive exclusion principle
what is the outocme species richness of the compeitive exclusion principle
species richness will be 1
what was Hutchinsons definition of a niche
a niche is an n-dimensional hypervolume
whos definition of a niche was that it is an n-dimensional hypervolume
Hutchinson
what is a fundamental niche
the n-dimensional hypervolume where all the ecological factors intersect in the absence of competitors
what is a realised niche
the part of fundamental niche when taking into account predators/competition
what is the term given to a fundamental niche when predators/competition is taken into accoutn
realided niche
what is the current view of a niche
the set of constraints on popn growth after taking into account interaction between (a)biotic enviro
outline the evoln of niche definition
1927-what a species does in ecosystem
1957-an n-dimensional hypervolume
2015-the set of constraints on pop grown
what was the first defintion of a niche
what a species does in ecosystem
what is Ellenbergs rule
most species grow best on their own at the SAME level of an enviro factor but peak in abundance at different levels when in comp with other species
which rule states that when species are grown alone they peak in abundance at same levels of enviro factor, but when grown with others/competition they peak in abundance at different levels
Ellenberg’s Rule
what are the 3 major forms of niche separation
- habitat
- resources
- range
outline how range separation of niches occur
species occupy different usually non-overlapping geographic ranges - allopatry
what is allopatric distribution an example of
niche separation by geographic range - species occupy different, non-overlapping ranges
how does niche separation by habitats occur
species have similar geographic range (sympatric) but live within differnt habitats
how does niche separation between sympatric species occur
through habitat separation eg. on bird might live on forest edge, while other in high canopy of forest interior
outline what happens in niche separation via resources
species may be sympatric, and living in same habitats but no overlap in resource use
eg. one warbler may glean insects from beneath leaves, other from topo
what niche separation is occuring in the following example:
one warbler may glean large insects form beneath leaves, while other gleans smaller insects from top of same leafq
niche separation by resources
what might the role of competition in a range/habitat/separation be manifestations of
former interactions:the Ghost of Competition past
what forms of separation do Darwins finches show
all 3 forms:
habitat
resource
geographic range
