EE21

Question 1

What is the competative exclusion principle?

Answer 1

you cant have more coexisting species than there are different niches
one will outcompete the other and equilibirum species richness =1

Question 2

What is hutchinsons niche?

Answer 2

an n: dimensional hypervolume
axis for every important quanitative trait
where all axis defines fundamental niche.

Question 3

What is the fundemental niche?

Answer 3

set of environmental conditions where in the absence of competitors or natural enemies, our species would be able to increase in number.

Question 4

what is the invasion criterion?

Answer 4

ability to increase when rare
population size is N
intrinsic growth rate=r
population change =dN/dt
dN/dt= rN
for increase must be positive. 
therefore r>0 
invasion criteria >0

Question 5

What is a niche?

Answer 5

a set of constraints on population growth
interaction between biotic and abiotic environment
- coexisiting species must exhibit one or more niche differences for equlilbirum
relatively long term non eq persistence of several species with indential niches is possible in theory.

Question 6

what is a realised niche?

Answer 6

part of the fundemental niche in which species occurs in field conditions.
subset of fundemental niche
species occur where competitors and natural enemies allow
max abundance in field doesnt neccessarily coincide with species optimum

Question 7

What is dN/dt outside of the fundemental niche?

Answer 7

0 able to increase when numbers are rare

Question 8

What is ellenburgs rule?

Answer 8

most species grow best on their own at the same level of an environmental factor like soil ph or water availability
they peak in abundance at different levels when in competition with other species

Question 9

Why is competion in range, habitat or resource separation controversial?

Answer 9

might be manifestations of former interactions
-ghosts of competitions past
might reflect on going competion between species

Question 10

What are the 3 seperatation types?

Answer 10

range
- species occup different ussually non overlapping geographical ranges - allopatry
habitat
- simialr ranges = sympatry but different habitats in ecosystem
resources
- same range and habitats likely to show no overlap in resource use.

Question 11

What does some of the best observational evidence of interspecific competion come from?

Answer 11

comparing the morphology and behaviour of the same species when it occurs in sympatry and allopatry with putitave competitors
eg. morphological differences like change in bill size
= character displacement.

Question 12

What is the guild of waders?

Answer 12

very dissimialr body size and bill size
seperated by feeding depth in sediment
belong to the same genus

Question 13

what is the guild of warblers

Answer 13

similar in body size and bill morphology
separated by habitat and foraging behabviour
belong to different genera

Question 14

What is the test for a vacant niche?

Answer 14

introduce a new species
if it estabilishes there was a vacant niche
if it doesnt establish tehre was not a vacant niche
means tyou cant recognise a vacant niche other than by addition of invading species