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0 Community Ecology Two-species interactions are classified by the impact each species 0 Community Ecology Two-species interactions are classified by the impact each species

0 Community Ecology Two-species interactions are classified by the impact each species - PowerPoint Presentation

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0 Community Ecology Two-species interactions are classified by the impact each species - PPT Presentation

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 ID: 812272

toads cane snakes species cane toads species snakes black areas niche prey mutualism diversity community eat present obligate

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Presentation Transcript

Slide1

0

Community Ecology

Slide2

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

Exercises

Slide23

The data are shown

below,

and a bar graph of the data is shown on the next slide.

Slide24

Slide25

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 found

Slide28

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 found

Slide29

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?