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Terms in this set (44)
What is competition?
Interaction between two or more individuals
both requiring the same limited resource
that when used or defended by one individual
reduces the survival or reproduction
of another individual.
What are two types of competition?
Consumers compete for ?
A resource is ?
something that is consumed and thus reduced.
A limited resource has?
higher demand than availability
Competition can _____ in intensity
when resources are limited
Which resource is most limited (i.e. limiting) can change
different times or in different populations
The Theory of Competition
A logistic equation based, mathematical model of intraspecific competition developed by lotka-volterra
Lotka - Volterra
incorporates interspecific competition. A separate
equation to represent the growth rate of each of the 2 competing populations
Like the logistic equation, in a lotka-volterra competition model, how close the # of inds in the population (N) is to K
still determines dN/dt, • But it is possible that adding individuals of another species also affects dN/dt
• Like logistic growth, in a lotka-volterra competition model, adding individuals to the population (i.e. ↑ing numerator) does what?
↓ the population's growth rate (dN/dt) since N is closer to K.
How can you raise the numerator by 1?
• add 1 individual of your spp
• Add 1 individual of a competing spp
If α =1 or B= 1: adding an ind of spp 1 or 2 has what effect on growth rate?
same effect on growth rate
- i.e. both intra- and interspecific competition have same effect
If α < 1 or B= 1 then adding an ind of the other spp
has what effect on growth rate?
less effect than adding an individual of your own spp
- i.e. intraspecific competition is > interspecific competition
If α >1 or B=1 then adding an ind of the other spp
has what type of effect on growth rate?
a > effect than adding an individual of your own spp
- i.e. interspecific competition > intraspecific competition
If α=0 or B= 0 then ?
there is no competition and the equation reduces to the logistic equation
what are further subdivisions of competition?
- direct interactions
- individuals "fight" for access to limiting resources.
-Can occur in both interspecific and intraspecific competition
Allelopathy can _____ fire frequency/intensity
thus _____ potential competitors
- indirect interactions;
- affect others from accessing resources
by consuming them first (food, water, sunlight)
Competition can limit?
distribution and abundance
Range of abiotic and biotic conditions
within which individuals of a species
can survive, grow and reproduce
Competitive Exclusion Principle
Two species cannot coexist indefinitely
on the same limiting resource
(i.e. w/ substantial niche overlap)
When niches overlap substantially,
there are ___ possible outcomes
Competitive exclusion and Coexistence via Resource (Niche) Partitioning
of 1 species
i.e. Inferior competitor extirpated (locally extinct)
A.G. Tansley's 1917 Test of the
Competitive Exclusion Principle
Closely related spp of
Galium (a plant) generally
do not occur together
Each spp grown alone
can grow on either soil
but survival and
growth higher on
When grown together
spp on nonpreferred
soil has reduced
survival and growth
(& goes locally extinct)
Coexistence via Resource (Niche) Partitioning
- Similar species can coexist if they share (partition) the resources
such that their niches no longer completely overlap
Natural selection drives competing species into different patterns of resource use and thus?
2 spp can partition a common limiting resource by specialization on what attributes?
Partitioning allows each spp to use a ____ of the resource
- Choose a particular size, color etc.
- Choose resources occurring in a specific location
- Use resources only during a specific time
Adaptive evolution can result in unique changes in
A)___, B)____ , or C)____
which allows specialization and niche partitioning
morphology, physiology, behavior
___________ differences due to adaptive
evolution result in resource (niche) partitioning
Adaptive evolution resulted in________allowing partitioning of the feeding aspect of niches
____and____ differences due to
adaptive evolution result in resource partitioning
Behavioral differentiation may be due to?
adaptive evolution OR a learned response
Morphological/ physiological differentiation occur via ?
adaptive evolution, thus are relatively fixed (not easily reversed)
Behavioral differentiation may be due to:
- adaptive evolution, and thus is fixed
- learned response, and thus is not fixed (i.e. can be changed)
a learned response, not adaptive evolution, resulted in ______ _____which led to temporal partitioning of feeding aspect of niches
A type of resource (niche) partitioning that occurs
ONLY where two species occur together
If 2 spp differ morphologically, behaviorally etc
only when together vs when alone
then this is ?
If the 2 spp have different morphologies etc...
whether alone or together then it is not?
Sets with similar terms
Ecology - Chapter 12: Competition
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