EE Lecture 21: Niches

Question 1

define niche

Answer 1

the ecological role of a species - the set of constraints on pop growth

Question 2

what are the consequences of niches

Answer 2

character displacement/competitive exclustion
adaptive radiation/extinction
inc biodiv or dec biodive

Question 3

what is the competitive exclusion principle (Gause’s Principle)

Answer 3

species with similar niches cant coexist in eqbm

Question 4

which principle states that species with similar niches cant coexist in eqbm

Answer 4

Gauses compeititive exclusion principle

Question 5

what is the outocme species richness of the compeitive exclusion principle

Answer 5

species richness will be 1

Question 6

what was Hutchinsons definition of a niche

Answer 6

a niche is an n-dimensional hypervolume

Question 7

whos definition of a niche was that it is an n-dimensional hypervolume

Answer 7

Hutchinson

Question 8

what is a fundamental niche

Answer 8

the n-dimensional hypervolume where all the ecological factors intersect in the absence of competitors

Question 9

what is a realised niche

Answer 9

the part of fundamental niche when taking into account predators/competition

Question 10

what is the term given to a fundamental niche when predators/competition is taken into accoutn

Answer 10

realided niche

Question 11

what is the current view of a niche

Answer 11

the set of constraints on popn growth after taking into account interaction between (a)biotic enviro

Question 12

outline the evoln of niche definition

Answer 12

1927-what a species does in ecosystem
1957-an n-dimensional hypervolume
2015-the set of constraints on pop grown

Question 13

what was the first defintion of a niche

Answer 13

what a species does in ecosystem

Question 14

what is Ellenbergs rule

Answer 14

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

Question 15

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

Answer 15

Ellenberg’s Rule

Question 16

what are the 3 major forms of niche separation

Answer 16

1. habitat
2. resources
3. range

Question 17

outline how range separation of niches occur

Answer 17

species occupy different usually non-overlapping geographic ranges - allopatry

Question 18

what is allopatric distribution an example of

Answer 18

niche separation by geographic range - species occupy different, non-overlapping ranges

Question 19

how does niche separation by habitats occur

Answer 19

species have similar geographic range (sympatric) but live within differnt habitats

Question 20

how does niche separation between sympatric species occur

Answer 20

through habitat separation eg. on bird might live on forest edge, while other in high canopy of forest interior

Question 21

outline what happens in niche separation via resources

Answer 21

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

Question 22

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

Answer 22

niche separation by resources

Question 23

what might the role of competition in a range/habitat/separation be manifestations of

Answer 23

former interactions:the Ghost of Competition past

Question 24

what forms of separation do Darwins finches show

Answer 24

all 3 forms:
habitat
resource
geographic range

Question 25

name some species where all forms of niche separation has occured

Answer 25

desert rodents/rats in USA
fruit feeding pigeons
guilds of waders
guilds of warblers

Question 26

how to test for a vacant niche

Answer 26

introduce new species, if it establishes then there WAS a vacant niche

Question 27

if a new species is introduced into a habitat and establishes, what does this tell you about the niche

Answer 27

there was a vacant niche

Question 28

what is allelopathy

Answer 28

individuals of one species release toxins that harm individuals of other species (not good for intraspec comp as all species could produce it)