15: Interspecific Competition

what does “symbiosis” mean?

living together in close association

Describe who benefits/does not in competition?

both are negative(-)

Describe who benefits/does not in predation & parasitism?

1) +

2) -

Describe who benefits/does not in mutualism & protocooperation?

both are positive (+)

Describe who benefits/does not in commensalism?

example?

1) +

2) 0 (neutral)

ex// birds uses a tree to build a nest

Describe who benefits/does not in association?

example?

1) +

2) 0 (neutral)

ex// crab uses spiky sea urchin to protect itself from predators

Describe who benefits/does not in amensalism?

ex?

1) -

2) 0 (neutral)

ex// Elk unintentionally sits on grass (bad for grass)

What is the competitive exclusion principle? (Gause’s principle)

No 2 species can occupy the same niche at the same time in the same place

Define a niche.

a multidimensional space within which an organism is able to exist

Difference between a niche & habitat?

niche→the “occupation” of role of an organism in a community

habitat→the “address” of an organism in a community

fundamental niche

potential space that an organism could occupy in the absence of competitors

realized niche

actual space that an organism occupies in the presence of competitors

define niche partitioning

division of resources between 2 or more competing species

Intraspecific vs. Interspecific competition

-what does each favor?

Intraspecific→competition of resources between SAME species

-favors generalization(minimizes competition between same species but increases competition between individuals of OTHER species)

Interspecific→competition of resources between DIFFERENT species

-favors specialization (minimizes comp. among individuals of different species but increases comp between same species)

Define a guild ?

example?

a group of functionally similar species which must divide a resource among themselves

ex// nectarivore guild

Potential outcomes of high niche overlap?

1) extinction of 1 or more species

2) emigration of 1 or more species

3) divergence

What is character displacement?

example?

behavior or morphological changes in which differences between species are exaggerated where their ranges overlap

ex// Darwin’s finches: In sympatry, beak sizes are different to reduce competition

Generalists occupy a ______ niche, while specialists occupy a ______ niche.

wide; narrow

What is ecological release? Where does this often occur?

expansion of the niche in the absence of competitors

-often occurs on oceanic islands where there are fewer species & less competitors

What is ecological equivalence?

closely related allopatric species occupying roughly the same niche, but DO NOT compete bc they do not coexist