Twospecies interactions are classified by the impact each species has on the other Thus a competitive interaction is one where the populations of each species are hurt by the presence of the other species usually because each species uses the same resources Niche partitioning enables species t ID: 423770
Download Presentation The PPT/PDF document "0 Community Ecology" is the property of its rightful owner. Permission is granted to download and print the materials on this web site for personal, non-commercial use only, and to display it on your personal computer provided you do not modify the materials and that you retain all copyright notices contained in the materials. By downloading content from our website, you accept the terms of this agreement.
Slide1
0
Community EcologySlide2
Two-species interactions are classified by the impact each species has on the other. Thus, a competitive interaction is one where the populations of each species are hurt by the presence of the other species, usually because each species uses the same resources. Niche partitioning enables species to coexist by
avoiding direct competition.
encouraging mutualistic interactions.
enabling prey to hide from predators.
creating new resources.
allowing abiotic factors, such as climate or nutrient availability, to influence the community.Slide3
Two-species interactions are classified by the impact each species has on the other. Thus, a competitive interaction is one where the populations of each species are hurt by the presence of the other species, usually because each species uses the same resources. Niche partitioning enables species to coexist by
avoiding direct competition.
encouraging mutualistic interactions.
enabling prey to hide from predators.
creating new resources.
allowing abiotic factors, such as climate or nutrient availability, to influence the community.Slide4
Which of the following best describes resource partitioning?
Two species can coevolve to share identical niches.
Competitive exclusion results in the success of the superior species.
A climax community is reached when no new niches are available.
Slight variations in niche allow similar species
to coexist.
Differential resource utilization results in the decrease in community species
diversity
.Slide5
Which of the following best describes resource partitioning?
Two species can coevolve to share identical niches.
Competitive exclusion results in the success of the superior species.
A climax community is reached when no new niches are available.
Slight variations in niche allow similar species
to coexist.
Differential resource utilization results in the decrease in community species
diversity
.Slide6
What is one difference between the fundamental niche and the realized niche?
The realized niche is larger.
The fundamental niche is determined by competitors
The realized niche is determined by abiotic resources.
Individuals will be found only in the realized
niche
.
The difference is called the occupied niche
.Slide7
What is one difference between the fundamental niche and the realized niche?
The realized niche is larger.
The fundamental niche is determined by competitors
The realized niche is determined by abiotic resources.
Individuals will be found only in the realized niche.
The difference is called the occupied niche
.Slide8
The common spiny mouse (Acomys cahirinus
) and the golden spiny mouse (
A.
russatus
) can occupy essentially the same ecological niche. They accomplish this by
character
displacement.
temporal
niche partitioning.
eating
different foods.
mating
at different times of
the year
.
each
occupying their functional niche.Slide9
The common spiny mouse (Acomys cahirinus
) and the golden spiny mouse (
A.
russatus
) can occupy essentially the same ecological niche. They accomplish this by
character
displacement.
temporal
niche partitioning.
eating
different foods.
mating
at different times of
the year
.
each
occupying their functional niche.Slide10
An obligate mutualism is an interaction in which at least one species cannot survive without the presence of the other species; a facultative mutualism is an interaction that benefits both species but is not required by either species. One reason facultative mutualism is more common is that
in an obligate mutualism, if the partner becomes extinct,
the obligate
mutualist
will also become extinct.
in a facultative mutualism, if the partner becomes extinct, the obligate
mutualist
will also become extinct.
in an obligate mutualism, the obligate
mutualist
is obliged to support its partner.
in a facultative mutualism, neither partner can depend on the other partner.
facultative mutualisms require longer periods of time to evolve.Slide11
An obligate mutualism is an interaction in which at least one species cannot survive without the presence of the other species; a facultative mutualism is an interaction that benefits both species but is not required by either species. One reason facultative mutualism is more common is that
in an obligate mutualism, if the partner becomes extinct,
the obligate
mutualist
will also become extinct.
in a facultative mutualism, if the partner becomes extinct, the obligate
mutualist
will also become extinct.
in an obligate mutualism, the obligate
mutualist
is obliged to support its partner.
in a facultative mutualism, neither partner can depend on the other partner.
facultative mutualisms require longer periods of time to evolve.Slide12
This graph shows the effect of soil pH on microbial diversity. One conclusion you should draw from this figure is
the higher the soil pH,
the higher the microbial
diversity.
the lower the soil pH,
the higher the microbial
diversity.
microbes eat
pH.
the scientists
couldn’
t
find
any acidic or basic soils
.
there appears to be an optimal pH value for
maximizing microbial diversity.Slide13
This graph shows the effect of soil pH on microbial diversity. One conclusion you should draw from this figure is
the higher the soil pH,
the higher the microbial
diversity.
the lower the soil pH,
the higher the microbial
diversity.
microbes eat
pH.
the scientists
couldn’
t
find
any acidic or basic soils
.
there appears to be an optimal pH value for
maximizing microbial diversity.Slide14
Look at the following figure, which shows a partial Chesapeake Bay food web. If sea nettles disappeared,
there would be fewer
fish eggs.
there would be more
striped bass.
there would be fewer
zooplankton.
striped bass would
have less food to eat.
sea nettles would
reinvade from the ocean.Slide15
Look at the following figure, which shows a partial Chesapeake Bay food web. If sea nettles disappeared,
there would be fewer
fish eggs.
there would be more
striped bass.
there would be fewer
zooplankton.
striped bass would
have less food to eat.
sea nettles would
reinvade from the ocean.Slide16
In rocky intertidal communities of western North America, Robert Paine removed
Pisaster
, an uncommon starfish, and measured species diversity. He found species diversity dropped dramatically when
Pisaster
was not present. From this, we can conclude that
uncommon species are more vital
to the community than common species.
predators are more vital to the
community than prey.
Pisaster
likely consumed
the dominant competitors.
Robert
Paine’
s
experiment
was poorly designed.
removing one species
always hurts the community.Slide17
In rocky intertidal communities of western North America, Robert Paine removed
Pisaster
, an uncommon starfish, and measured species diversity. He found species diversity dropped dramatically when
Pisaster
was not present. From this, we can conclude that
uncommon species are more vital
to the community than common species.
predators are more vital to the
community than prey.
Pisaster
likely consumed
the dominant competitors.
Robert
Paine’
s
experiment
was poorly designed.
removing one species
always hurts the community.Slide18
Disturbance is an important component of succession because it
a) removes
keystone species.
b) changes
the biome from one kind to another.
c) introduces
invasive species.
d) is
associated with humans.
e) tends
to promote earlier successional
stages.Slide19
Disturbance is an important component of succession because it
a) removes
keystone species.
b) changes
the biome from one kind to another.
c) introduces
invasive species.
d) is
associated with humans.
e) tends
to promote earlier successional
stages.Slide20
Which of the following explains mutualism?
−
/
−
+
/
−
+
/
+
Slide21
Which of the following explains mutualism?
−
/
−
+
/
−
+
/
+
Slide22
In
the first part of
an experiment
, researchers collected 12 black snakes (
Pseudechis
porphyriacus
) from areas where cane toads had existed for 40–60 years and another 12 from areas free of cane toads. They offered the snakes either a freshly killed native frog (
Limnodynastes
peronii
, a species the snakes commonly eat) or a freshly killed cane toad from which the toxin gland had been removed (making the toad nonpoisonous).
Scientific Skills
ExercisesSlide23
The data are shown
below,
and a bar graph of the data is shown on the next slide.Slide24Slide25
a) Black
snakes will
not
prey on cane toads in areas where cane toads have been present for 40–60
years
.
b) Black
snakes will prey on cane toads in areas where cane toads have been present for 40–60 years, but not when offered a native frog instead.
c) Black
snakes in areas where cane toads have been present for 40–60 years are just as likely to prey on cane toads as on native frogs.
What do the data suggest about the effects of cane toads on the predatory behavior of black snakes in areas where the toads have been present for 40–60 years? Slide26
a) Black
snakes will
not
prey on cane toads in areas where cane toads have been present for 40–60
years
.
b) Black
snakes will prey on cane toads in areas where cane toads have been present for 40–60 years, but not when offered a native frog instead.
c) Black
snakes in areas where cane toads have been present for 40–60 years are just as likely to prey on cane toads as on native frogs.
What do the data suggest about the effects of cane toads on the predatory behavior of black snakes in areas where the toads have been present for 40–60 years? Slide27
a) In
those areas, black snakes will
not
prey on cane toads.
b) In
those areas, black snakes are equally likely to prey on native frogs and cane toads.
c) In
those areas, black snakes will prey on cane toads, but they are more likely to prey on native frogs.
What do the data suggest about the predatory behavior of black snakes in areas where cane toads are
not
currently foundSlide28
a) In
those areas, black snakes will
not
prey on cane toads.
b) In
those areas, black snakes are equally likely to prey on native frogs and cane toads.
c) In
those areas, black snakes will prey on cane toads, but they are more likely to prey on native frogs.
What do the data suggest about the predatory behavior of black snakes in areas where cane toads are
not
currently foundSlide29
a) A
much higher percentage of black snakes in those areas would eat the cane toads offered to them.
b) The
results would not change significantly.
c) A
much lower percentage of black snakes in those areas would eat the cane toads offered to them.
d) A
much higher percentage of black snakes in those areas would eat the cane toads offered to them, and a lower percentage would eat the native frogs offered to them
.
Suppose an enzyme that deactivates the cane toad toxin evolves in black snakes living in areas with cane toads. If the researchers repeated this experiment, predict how the results would change for areas where cane toads have been present for 40–60 years
.Slide30
a) A
much higher percentage of black snakes in those areas would eat the cane toads offered to them.
b) The
results would not change significantly.
c) A
much lower percentage of black snakes in those areas would eat the cane toads offered to them.
d) A
much higher percentage of black snakes in those areas would eat the cane toads offered to them, and a lower percentage would eat the native frogs offered to them
.
Suppose an enzyme that deactivates the cane toad toxin evolves in black snakes living in areas with cane toads. If the researchers repeated this experiment, predict how the results would change for areas where cane toads have been present for 40–60 years
.Slide31
a) Exposure
to cane toads does not appear to have a selective effect on black snake populations.
b) Exposure
to cane toads
appears
to be selecting for
black
snakes that are less
affected
by
the
toxin.
c) Exposure
to cane toads
appears
to be selecting for
black snakes
that are more
affected
by
the
toxin.
d) Exposure
to cane toads
appears
to be selecting for
black snakes
that are
faster swimmers
.
Based on the scatter plot, what conclusion would you draw about whether exposure to cane toads is having a selective effect on black snakes in this study? Slide32
a) Exposure
to cane toads does not appear to have a selective effect on black snake populations.
b) Exposure
to cane toads
appears
to be selecting for
black
snakes that are less
affected
by
the
toxin.
c) Exposure
to cane toads
appears
to be selecting for
black snakes
that are more
affected
by
the
toxin.
d) Exposure
to cane toads
appears
to be selecting for
black snakes
that are
faster swimmers
.
Based on the scatter plot, what conclusion would you draw about whether exposure to cane toads is having a selective effect on black snakes in this study?