Competition 1 Flashcards
Individuals in populations usually
do not live in isolation of other species
species interactions are
the effect that a pair of organisms have on eachother
trophic interactions
relationships about feeding
reproductive interactions
interactions about reproduction
Habitat related
species creating habitats
Competition
- -
mutualism
+ +
exploitation
+ -
amensalism
- 0
Commensalism
+ 0
Neutralism
0 0
what breaks exponential growth at K/2?
Intraspecific competition
Intraspecific competition
within species competition
Interspecific competition
between species competition
Different modes of competition
interference competition- direct
exploitative competition - indirect, individuals do not interact
does interspecific or intraspecific have more of an effect on population growth
intraspecific
intraspecific competition leads to a fitness reduction in ______ individual(s)
both
intraspecific and interspecific competition can be both
direct and indirect
if resources are infinite, what does not occur?
intraspecific competition
in interspecific competition, we can model which species will win via
lotka volterra model
what happens when 2 species share the same niche?
interspecific competition
Interference competition
-direct aggressive interaction between individuals
-most common in animals
Exploitative competition
-indirect competition to secure resources first
-more common in plants
Phillip Grime’s proposal
competition is at its lowest point when there is a high resource availability because population will be highest
David tilman- later supported by richard reader
competition is at both high and now productivity, but competitive in high productive enviros is aboveground, while competition in low production areas is belowgroundtan
tansley competition in galium
saxatile grows exclusively on acidic soils
pumilum grows on basic soils
he grew both and they could germinate when alone, however
pumilum was outcompeted in acidic soil vice versa for other mf
what was tansley’s study evidence for?
realized vs fundamental niche
connell- comp in barnacles
interspecific competition, enviro stress and predation responsible for contrasting distribution along intertidal
competetive exclusion principle
two species with same niche cannot co-exist aka GAUSE’S LAW
stable coexistance rarely occurs, what happens instead?
species occupy realized niche
when does exclusion not occur?
-when disease and predation are the bigger limiting factors
-in extreme or highly variable environments
_______ is a selective force in evolution
competition
what does competition select for??
- frequency of the most competitive,
- frequency of those who avoid competition
what are examples of avoiding competition? (2)
1.niche divergence–> resource partitioning, conditional partitioning
2.character displacement
character displacement
changes in the characteristics of a species population as a consequence of natural selection for reduced competition in regions where species co-occur
Just because related species show different adaptations and occupy the same geographical area
DOES not mean they evolved as a result of character displacement
7 ways to test for non character displacement
- random chance ruled out
- phenotypic difference have genetic basis
3.phenotypic differences in sympatry should result from evolutionary shifts - phenotypic differences should relate to resource use
- sites of sympatry and allopatry should not differ in food or other environmental features
- evidence that similar phenotypes actually compete for resources
benthic vs limnetic species
benthic occupies bottom of le water
limnetic occupies top
exploitative competition in plants
- start as seedlings, hella mfs, low biomass
- intermediate amt of mfs still low biomass
- mfs outcompete others, low numbers, high biomass
