BCOR Exam II

What happens when individuals share one resource pool

crowding creates intraspecific competition

What happens when different species share a limiting resource

each can reduce the other’s growth

Define Competition

a negative interaction in which organisms reduce one another’s access to limiting resources

a resource only creates competition when it is ____________

limiting

Limiting Resource

a resource whose scarcity restricts population growth

No scarcity means ______________

little to no competition

define intraspecific competition

competition among members of the same species for shared resources

as N approaches K, crowding increasingly _________ growth

Supresses

what model is best used for intraspecific competition?

logistic growth

Logistic growth equation

what term of the logistic growth summarizes intraspecific competition?

(1-N/K)

define interspecific competition

competition between species for a common resource

Graph of resource overlap

What would a graph look like to show less overlap

if there is less resource overlap then there is less ______________

competition

resource separation can make coexistence _______

easier

define exploitation competition

indirect competition through depletion of a shared resource

define interference competition

direct competition that reduces another organism’s ability to acquire resources

define allelopathy

chemical interference that suppresses a competitor’s germination or growth

allelopathy changes access ______ resources are taken

before

effect of allelopathy

released compounds reduce competitor performance

define pre-emptive competition

competition for space when early occupants prevent later establishment

in what organisms is pre-emptive competition common?

sessile plants and marine invertebrates

T/F: Is space considered a limiting resource?

True

List the actions of the competitor, resource pathway, and example of EXPLOITATION

Acts: indirectly

Resource pathway: depletes shared resource

Example: Shared food/soil resources

List the actions of the competitor, resource pathway, and example of INTERFERENCE

Acts: directly

Resource pathway: reduces access or uptake

Example: Territoriality/allelopathy

niche overlap determines where competition is _______ and whether environmental differences allow coexistence

strongest

define hutchinson’s niche

an N-dimensional hyper volume for which dN/dt is greater than 0

define ecological niche

the set of environmental conditions where population growth is positive

possible axes for an graph of a niche

temperature

moisture

pH

food

size

habitat structure

a niche can be visualized ______ dimension at a time

one

inside the range of a niche graph, conditions allow ________ population growth

positive

define fundamental niche

conditions a species can occupy when considered alone

define realized niche

the portion of the niche occupied in the presence of other species

competition can make the realized niche _______ than the fundamental niche

smaller

which environment represents the fundamental niche: species alone

environment 1

which environment represents the realized niche: presence of competitors restricts occupancy

environment 2

Joseph Connel: competition can _______ a realized niche

shrink

What did joseph connel study?

two barnacle species

the graph of same resource use

the graph of different resource use

evolutionary adjustment
before: trait distributions overlap _______
after: average traits diverge and overlap is ________

strongly; reduced

Lotka-Volterra Competition Model

What does “α“ represent

the effect of species 2 on species 1

Hutchinson’s Niche

a n-dimensional hyper volume where dN/dt > 0

define ecological niche

the set of environmental conditions where populations growth is positive

define fundamental niche

conditions a species can occupy when considered alone

define realized niche

the portion of niche

this is a graph of ____________

competitive exclusion

this is a graph of ____________

competitive coexistence

define competitive exclusion

Two species that depend on the same limiting
resource in the same way cannot coexist
indefinitely under constant conditions; one
eventually excludes the other

the more completely two species overlap in resource use the ________ stable coexistence becomes

harder

define niche partitioning

dividing up the resources such that each species specializes on a different aspect of the resource spectrum

what are the three main ways to partition a niche

spatial, temporal, behaviorally

partitioning a niche: define spatial