55_lecture_presentation_0.ppt campbell 8
EviRiolina
35 views
61 slides
Jun 29, 2024
Slide 1 of 61
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
About This Presentation
ringkasan buku campbell
Slide Content
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
PowerPoint
®
Lecture Presentations for
Biology
Eighth Edition
Neil Campbell and Jane Reece
Lectures by Chris Romero, updated by Erin Barley with contributions from Joan Sharp
Chapter 55
Ecosystems
PowerPoint
®
Lecture Presentations for
Biology
Eighth Edition
Neil Campbell and Jane Reece
Lectures by Chris Romero, updated by Erin Barley with contributions from Joan Sharp
Chapter 55
Ecosystems
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Overview: Ecosystems
•An ecosystemconsists of all the organisms living in a
community, as well as the abiotic factors with which
they interact.
•Ecosystems range from a microcosm, such as an
aquarium, to a large area such as a lake or forest.
•Regardless of an ecosystem’s size, its dynamics
involve two main processes: energy flow and
chemical cycling.
•Energy flows through ecosystems while matter cycles
within them.
Overview: Ecosystems
•An ecosystemconsists of all the organisms living in a
community, as well as the abiotic factors with which
they interact.
•Ecosystems range from a microcosm, such as an
aquarium, to a large area such as a lake or forest.
•Regardless of an ecosystem’s size, its dynamics
involve two main processes: energy flow and
chemical cycling.
•Energy flows through ecosystems while matter cycles
within them.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Physical laws govern energy flow and chemical
cycling in ecosystems
•Laws of physics and chemistry apply to the
transformations of energy and matterwithin the
ecosystems, particularly energy flow.
•The first law of thermodynamicsstates that energy
cannot be created or destroyed, only transformed.
Energy enters an ecosystem as solar radiation, is
conserved, and is lost from organisms as heat.
•The second law of thermodynamicsstates that every
exchange of energy increases the entropyof the
universe. In an ecosystem, energy conversions are
not completely efficient, and some energy is always
lost as heat.
Physical laws govern energy flow and chemical
cycling in ecosystems
•Laws of physics and chemistry apply to the
transformations of energy and matterwithin the
ecosystems, particularly energy flow.
•The first law of thermodynamicsstates that energy
cannot be created or destroyed, only transformed.
Energy enters an ecosystem as solar radiation, is
conserved, and is lost from organisms as heat.
•The second law of thermodynamicsstates that every
exchange of energy increases the entropyof the
universe. In an ecosystem, energy conversions are
not completely efficient, and some energy is always
lost as heat.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Conservation of Mass
•The law of conservation of mass states that
matter cannot be created or destroyed.
•Chemical elements are continually recycled
within ecosystems.
•In a forest ecosystem, most nutrients enter as
dust or solutes in rain and are carried away in
water.
•Ecosystems are open systems, absorbing
energy and mass and releasing heat and waste
products.
Conservation of Mass
•The law of conservation of mass states that
matter cannot be created or destroyed.
•Chemical elements are continually recycled
within ecosystems.
•In a forest ecosystem, most nutrients enter as
dust or solutes in rain and are carried away in
water.
•Ecosystems are open systems, absorbing
energy and mass and releasing heat and waste
products.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Energy, Mass, and Trophic Levels
•Autotrophsbuild organic molecules themselves
using photosynthesis or chemosynthesis as an
energy source.
•Heterotrophsdepend on the biosynthetic
output of other organisms.
•Energy and nutrients pass from primary
producers (autotrophs) to primary
consumers (herbivores) to secondary
consumers (carnivores) to tertiary
consumers (carnivores that feed on other
carnivores).
Energy, Mass, and Trophic Levels
•Autotrophsbuild organic molecules themselves
using photosynthesis or chemosynthesis as an
energy source.
•Heterotrophsdepend on the biosynthetic
output of other organisms.
•Energy and nutrients pass from primary
producers (autotrophs) to primary
consumers (herbivores) to secondary
consumers (carnivores) to tertiary
consumers (carnivores that feed on other
carnivores).
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
•Detritivores,or decomposers, are consumers
that derive their energy from detritus, nonliving
organic matter.
•Prokaryotes and fungi are important
detritivores.
•Decomposition connects all trophic levels.
•Detritivores,or decomposers, are consumers
that derive their energy from detritus, nonliving
organic matter.
•Prokaryotes and fungi are important
detritivores.
•Decomposition connects all trophic levels.
Fungi
decomposing
a dead tree
decomposing
a dead tree
Energy and Nutrient
Dynamics in an
Ecosystem
Microorganisms
and other
detritivores
Tertiary consumers
Secondary
consumers
Primary consumers
Primary producers
Detritus
Heat
Sun
Chemical cycling
Key
Energy flow
Dynamics in an
Ecosystem
Microorganisms
and other
detritivores
Tertiary consumers
Secondary
consumers
Primary consumers
Primary producers
Detritus
Heat
Sun
Chemical cycling
Key
Energy flow
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Energy and other limiting factors control primary
production in ecosystems
•Primary productionin an ecosystem is the amount of
light energy converted to chemical energy by
autotrophs during a given time period. The extent of
photosynthetic productionsets the spending limit for
an ecosystem’s energy budget.
•The amount of solar radiation reaching the Earth’s
surface limits photosynthetic output of ecosystems.
•Only a small fraction of solar energy actually strikes
photosynthetic organisms, and even less is of a
usable wavelength.
Energy and other limiting factors control primary
production in ecosystems
•Primary productionin an ecosystem is the amount of
light energy converted to chemical energy by
autotrophs during a given time period. The extent of
photosynthetic productionsets the spending limit for
an ecosystem’s energy budget.
•The amount of solar radiation reaching the Earth’s
surface limits photosynthetic output of ecosystems.
•Only a small fraction of solar energy actually strikes
photosynthetic organisms, and even less is of a
usable wavelength.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Gross and Net Primary Production
•Total primary production is known as the
ecosystem’s gross primary production = GPP
•Net primary production = NPPis GPP minus
energy used by primary producers for respiration.
NPP = GPP -Respiration
•Only NPP is available to consumers.
•Standing cropis thetotal biomass of
photosynthetic autotrophs at a given time.
Gross and Net Primary Production
•Total primary production is known as the
ecosystem’s gross primary production = GPP
•Net primary production = NPPis GPP minus
energy used by primary producers for respiration.
NPP = GPP -Respiration
•Only NPP is available to consumers.
•Standing cropis thetotal biomass of
photosynthetic autotrophs at a given time.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
•Tropical rain forests, estuaries, and coral reefs
are among the most productive ecosystems
per unit area.
•Marine ecosystems are relatively unproductive
per unit area, but contribute much to global net
primary production because of their volume.
•Tropical rain forests, estuaries, and coral reefs
are among the most productive ecosystems
per unit area.
•Marine ecosystems are relatively unproductive
per unit area, but contribute much to global net
primary production because of their volume.
Net primary production (kg carbon/m
2
·yr)
0 1 2 3
·
Global net primary production in 2002
Global net primary production in 2002
2
·yr)
0 1 2 3
·
Global net primary production in 2002
Global net primary production in 2002
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Primary Production in Aquatic Ecosystems
•In marine and freshwater ecosystems, both
light and nutrients control primary production.
•Depth of light penetration affects primary
production in the photic zone of an ocean or
lake.
Primary Production in Aquatic Ecosystems
•In marine and freshwater ecosystems, both
light and nutrients control primary production.
•Depth of light penetration affects primary
production in the photic zone of an ocean or
lake.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Nutrient Limitation
•More than light, nutrients limit primary production
in geographic regions of the ocean and in lakes.
•A limiting nutrient is the element that must be
added for production to increase in an area.
•Nitrogen andphosphorous are typically the
nutrients that most oftenlimit marine production.
•Nutrient enrichment experiments confirmed that
nitrogen was limiting phytoplankton growth.
Nutrient Limitation
•More than light, nutrients limit primary production
in geographic regions of the ocean and in lakes.
•A limiting nutrient is the element that must be
added for production to increase in an area.
•Nitrogen andphosphorous are typically the
nutrients that most oftenlimit marine production.
•Nutrient enrichment experiments confirmed that
nitrogen was limiting phytoplankton growth.
Which nutrient limits phytoplankton production along the coast
of Long Island?
Ammonium
enriched
Phosphate
enriched
Unenriched
control
A B C D E F G
30
24
18
12
6
0
Collection site
Phytoplankton density
(millions of cells per mL)
of Long Island?
Ammonium
enriched
Phosphate
enriched
Unenriched
control
A B C D E F G
30
24
18
12
6
0
Collection site
Phytoplankton density
(millions of cells per mL)
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
•Upwelling of nutrient-rich watersin parts of the
oceans contributes to regions of high primary
production.
•The addition of large amounts of nutrients to
lakes has a wide range of ecological impacts.
•In some areas, sewage runoffhas caused
eutrophicationof lakes, which can lead to
loss of most fish species.
•Upwelling of nutrient-rich watersin parts of the
oceans contributes to regions of high primary
production.
•The addition of large amounts of nutrients to
lakes has a wide range of ecological impacts.
•In some areas, sewage runoffhas caused
eutrophicationof lakes, which can lead to
loss of most fish species.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Primary Production in Terrestrial Ecosystems
•In terrestrial ecosystems, temperature and
moisture affect primary production on a large
scale.
•Actual evapotranspiration can represent the
contrast between wet and dry climates.
•Actual evapotranspirationis the water
annually transpired by plants and evaporated
from a landscape. It is related to net primary
production.
•On a local scale, a soil nutrient is often the
limiting factor in primary production.
Primary Production in Terrestrial Ecosystems
•In terrestrial ecosystems, temperature and
moisture affect primary production on a large
scale.
•Actual evapotranspiration can represent the
contrast between wet and dry climates.
•Actual evapotranspirationis the water
annually transpired by plants and evaporated
from a landscape. It is related to net primary
production.
•On a local scale, a soil nutrient is often the
limiting factor in primary production.
Net primary production (g/m
2
·
yr)
Relationship betweennet primary productionand actualevapotranspirationin six
terrestrial ecosystems
Tropical forest
Actual evapotranspiration (mm H
2O/yr)
Temperate forest
Mountain coniferous forest
Temperate grassland
Arctic tundra
Desert
shrubland
1,5001,0005000
0
1,000
2,000
3,000
·
2
·
yr)
Relationship betweennet primary productionand actualevapotranspirationin six
terrestrial ecosystems
Tropical forest
Actual evapotranspiration (mm H
2O/yr)
Temperate forest
Mountain coniferous forest
Temperate grassland
Arctic tundra
Desert
shrubland
1,5001,0005000
0
1,000
2,000
3,000
·
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Energy transfer between trophic levels is typically
only 10% efficient
•Secondary productionof an ecosystem is the
amount of chemical energy in food converted
to new biomassduring a given period of time.
•When a caterpillar feeds on a leaf, only about
one-sixth of the leaf’s energy is used for
secondary production.
•An organism’s production efficiencyis the
fraction of energy stored in food that is not
used for respiration.
Energy transfer between trophic levels is typically
only 10% efficient
•Secondary productionof an ecosystem is the
amount of chemical energy in food converted
to new biomassduring a given period of time.
•When a caterpillar feeds on a leaf, only about
one-sixth of the leaf’s energy is used for
secondary production.
•An organism’s production efficiencyis the
fraction of energy stored in food that is not
used for respiration.
Energy
partitioning
within a link
of the food
chain
Cellular
respiration
100 J
Growth (new biomass)
Feces
200 J
33 J
67 J
Plant material
eaten by caterpillar
partitioning
within a link
of the food
chain
Cellular
respiration
100 J
Growth (new biomass)
Feces
200 J
33 J
67 J
Plant material
eaten by caterpillar
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Trophic Efficiency and Ecological Pyramids
•Trophic efficiencyis the percentage of
production transferred from one trophic level to
the next. 10% Law of Energy Transfer
•Trophic efficiency is multiplied over the length
of a food chain.
•Approximately 0.1% of chemical energy fixed
by photosynthesis reaches a tertiary consumer.
•A pyramid of net production represents the loss
of energy with each transfer in a food chain.
Trophic Efficiency and Ecological Pyramids
•Trophic efficiencyis the percentage of
production transferred from one trophic level to
the next. 10% Law of Energy Transfer
•Trophic efficiency is multiplied over the length
of a food chain.
•Approximately 0.1% of chemical energy fixed
by photosynthesis reaches a tertiary consumer.
•A pyramid of net production represents the loss
of energy with each transfer in a food chain.
Primary
producers
100 J
1,000,000 J of sunlight
10 J
1,000 J
10,000 J
Primary
consumers
Secondary
consumers
Tertiary
consumers
producers
100 J
1,000,000 J of sunlight
10 J
1,000 J
10,000 J
Primary
consumers
Secondary
consumers
Tertiary
consumers
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
•In a biomass pyramid, each tier represents the dry
weight of all organisms in one trophic level.
•Most biomass pyramids show a sharp decrease at
successively higher trophic levels..
•Certain aquatic ecosystems have inverted biomass
pyramids: producers (phytoplankton) are consumed so
quickly that they are outweighed by primary
consumers.
•Turnover time is a ratio of the standing crop biomass
to production.
•In a biomass pyramid, each tier represents the dry
weight of all organisms in one trophic level.
•Most biomass pyramids show a sharp decrease at
successively higher trophic levels..
•Certain aquatic ecosystems have inverted biomass
pyramids: producers (phytoplankton) are consumed so
quickly that they are outweighed by primary
consumers.
•Turnover time is a ratio of the standing crop biomass
to production.
Pyramids of biomass = standing crop:
(a) Most ecosystems(data from a Florida bog)
Primary producers (phytoplankton)
(b) Some aquatic ecosystems(data from the English Channel)
Trophic level
Tertiary consumers
Secondary consumers
Primary consumers
Primary producers
Trophic level
Primary consumers (zooplankton)
Dry mass
(g/m
2
)
Dry mass
(g/m
2
)
1.5
11
37
809
21
4
(a) Most ecosystems(data from a Florida bog)
Primary producers (phytoplankton)
(b) Some aquatic ecosystems(data from the English Channel)
Trophic level
Tertiary consumers
Secondary consumers
Primary consumers
Primary producers
Trophic level
Primary consumers (zooplankton)
Dry mass
(g/m
2
)
Dry mass
(g/m
2
)
1.5
11
37
809
21
4
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
•Dynamics of energy flow in ecosystems have
important implications for the human population.
•Eating meat is a relatively inefficient way of tapping
photosynthetic production.
•Worldwide agriculture could feed many more people if
humans ate only plant material.
•Most terrestrial ecosystems have large standing crops
despite the large numbers of herbivores.
•Dynamics of energy flow in ecosystems have
important implications for the human population.
•Eating meat is a relatively inefficient way of tapping
photosynthetic production.
•Worldwide agriculture could feed many more people if
humans ate only plant material.
•Most terrestrial ecosystems have large standing crops
despite the large numbers of herbivores.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
•The green world hypothesisproposes
several factors that keep herbivores in check:
–Plant defenses
–Limited availability of essential nutrients
–Abiotic factors
–Intraspecific competition
–Interspecific interactions
•The green world hypothesisproposes
several factors that keep herbivores in check:
–Plant defenses
–Limited availability of essential nutrients
–Abiotic factors
–Intraspecific competition
–Interspecific interactions
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Biological and geochemical processes cycle
nutrients between organic and inorganic parts of
an ecosystem
•Life depends on recycling chemical elements.
•Nutrient circuits in ecosystems involve biotic
and abiotic components and are often called
biogeochemical cycles.
Biological and geochemical processes cycle
nutrients between organic and inorganic parts of
an ecosystem
•Life depends on recycling chemical elements.
•Nutrient circuits in ecosystems involve biotic
and abiotic components and are often called
biogeochemical cycles.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Biogeochemical Cycles
•Gaseous carbon, oxygen, sulfur, and nitrogen
occur in the atmosphere and cycle globally.
•Less mobile elements such as phosphorus,
potassium, and calcium cycle on a more local
level.
•A model of nutrient cycling includes main
reservoirs of elements and processes that
transfer elements between reservoirs.
•All elements cycle between organic and
inorganic reservoirs.
Biogeochemical Cycles
•Gaseous carbon, oxygen, sulfur, and nitrogen
occur in the atmosphere and cycle globally.
•Less mobile elements such as phosphorus,
potassium, and calcium cycle on a more local
level.
•A model of nutrient cycling includes main
reservoirs of elements and processes that
transfer elements between reservoirs.
•All elements cycle between organic and
inorganic reservoirs.
Nutrient
Cycling
Reservoir A Reservoir B
Organic
materials
available
as nutrients
Fossilization
Organic
materials
unavailable
as nutrients
Reservoir DReservoir C
Coal, oil,
peat
Living
organisms,
detritus
Burning
of fossil fuels
Respiration,
decomposition,
excretion
Assimilation,
photosynthesis
Inorganic
materials
available
as nutrients
Inorganic
materials
unavailable
as nutrients
Atmosphere,
soil, water
Minerals
in rocks
Weathering,
erosion
Formation of
sedimentary rock
Cycling
Reservoir A Reservoir B
Organic
materials
available
as nutrients
Fossilization
Organic
materials
unavailable
as nutrients
Reservoir DReservoir C
Coal, oil,
peat
Living
organisms,
detritus
Burning
of fossil fuels
Respiration,
decomposition,
excretion
Assimilation,
photosynthesis
Inorganic
materials
available
as nutrients
Inorganic
materials
unavailable
as nutrients
Atmosphere,
soil, water
Minerals
in rocks
Weathering,
erosion
Formation of
sedimentary rock
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
•In studying cycling of water, carbon, nitrogen,
and phosphorus, ecologists focus on four
factors:
–Each chemical’s biological importance
–Forms in which each chemical isavailable or
used by organisms
–Major reservoirsfor each chemical
–Key processes driving movementof each
chemical through its cycle.
•In studying cycling of water, carbon, nitrogen,
and phosphorus, ecologists focus on four
factors:
–Each chemical’s biological importance
–Forms in which each chemical isavailable or
used by organisms
–Major reservoirsfor each chemical
–Key processes driving movementof each
chemical through its cycle.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
The Water Cycle
•Water is essential to all organisms.
•97% of the biosphere’s water is contained in
the oceans, 2% is in glaciers and polar ice
caps, and 1% is in lakes, rivers, and
groundwater.
•Water moves by the processes of evaporation,
transpiration, condensation, precipitation, and
movement through surface and groundwater.
The Water Cycle
•Water is essential to all organisms.
•97% of the biosphere’s water is contained in
the oceans, 2% is in glaciers and polar ice
caps, and 1% is in lakes, rivers, and
groundwater.
•Water moves by the processes of evaporation,
transpiration, condensation, precipitation, and
movement through surface and groundwater.
Nutrient
Cycles:
Water Cycle
Precipitation
over land
Transport
over land
Solar energy
Net movement of
water vapor by wind
Evaporation
from ocean
Percolation
through
soil
Evapotranspiration
from land
Runoff and
groundwater
Precipitation
over ocean
Cycles:
Water Cycle
Precipitation
over land
Transport
over land
Solar energy
Net movement of
water vapor by wind
Evaporation
from ocean
Percolation
through
soil
Evapotranspiration
from land
Runoff and
groundwater
Precipitation
over ocean
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
The Carbon Cycle
•Carbon-based organic molecules are essential
to all organisms.
•Carbon reservoirs include fossil fuels, soils and
sediments, solutes in oceans, plant and animal
biomass, and the atmosphere.
•CO
2is taken up and released through
photosynthesis and respiration; additionally,
volcanoes and the burning of fossil fuels
contribute CO
2to the atmosphere.
The Carbon Cycle
•Carbon-based organic molecules are essential
to all organisms.
•Carbon reservoirs include fossil fuels, soils and
sediments, solutes in oceans, plant and animal
biomass, and the atmosphere.
•CO
2is taken up and released through
photosynthesis and respiration; additionally,
volcanoes and the burning of fossil fuels
contribute CO
2to the atmosphere.
Nutrient
Cycles:
Carbon
Cycle
Higher-level
consumersPrimary
consumers
Detritus
Burning of
fossil fuels
and wood
Phyto-
plankton
Cellular
respiration
Photo-
synthesis
Photosynthesis
Carbon compounds
in water
Decomposition
CO
2in atmosphere
Cycles:
Carbon
Cycle
Higher-level
consumersPrimary
consumers
Detritus
Burning of
fossil fuels
and wood
Phyto-
plankton
Cellular
respiration
Photo-
synthesis
Photosynthesis
Carbon compounds
in water
Decomposition
CO
2in atmosphere
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
The Terrestrial Nitrogen Cycle
•Nitrogen is a component of amino acids, proteins, and
nucleic acids
•The main reservoir of nitrogen is the atmosphere (N
2),
though this nitrogen must be converted toNH
4
+
or
NO
3
–
foruptake by plants, via nitrogen fixation by
bacteria.
•Organic nitrogen is decomposed to NH
4
+
by
ammonification, and NH
4
+
is decomposed to NO
3
–
by
nitrification.
•Denitrification converts NO
3
–
back to N
2
The Terrestrial Nitrogen Cycle
•Nitrogen is a component of amino acids, proteins, and
nucleic acids
•The main reservoir of nitrogen is the atmosphere (N
2),
though this nitrogen must be converted toNH
4
+
or
NO
3
–
foruptake by plants, via nitrogen fixation by
bacteria.
•Organic nitrogen is decomposed to NH
4
+
by
ammonification, and NH
4
+
is decomposed to NO
3
–
by
nitrification.
•Denitrification converts NO
3
–
back to N
2
Nutrient
Cycles:
Nitrogen
Cycle
Decomposers
N
2in atmosphere
Nitrification
Nitrifying
bacteria
Nitrifying
bacteria
Denitrifying
bacteria
Assimilation
NH
3 NH
4 NO
2
NO
3
+ –
–
Ammonification
Nitrogen-fixing
soil bacteria
Nitrogen-fixing
bacteria
Cycles:
Nitrogen
Cycle
Decomposers
N
2in atmosphere
Nitrification
Nitrifying
bacteria
Nitrifying
bacteria
Denitrifying
bacteria
Assimilation
NH
3 NH
4 NO
2
NO
3
+ –
–
Ammonification
Nitrogen-fixing
soil bacteria
Nitrogen-fixing
bacteria
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
The Phosphorus Cycle
•Phosphorus is a major constituent of nucleic
acids, phospholipids, and ATP.
•Phosphate (PO
4
3–
) is the most important
inorganic form of phosphorus.
•The largest reservoirs are sedimentary rocks of
marine origin, the oceans, and organisms.
•Phosphate binds with soil particles, and
movement is often localized.
The Phosphorus Cycle
•Phosphorus is a major constituent of nucleic
acids, phospholipids, and ATP.
•Phosphate (PO
4
3–
) is the most important
inorganic form of phosphorus.
•The largest reservoirs are sedimentary rocks of
marine origin, the oceans, and organisms.
•Phosphate binds with soil particles, and
movement is often localized.
Nutrient
Cycles:
Phosphorous
Cycle
Leaching
Consumption
Precipitation
Plant
uptake
of PO
4
3–
Soil
Sedimentation
Uptake
Plankton
Decomposition
Dissolved PO
4
3–
Runoff
Geologic
uplift
Weathering
of rocks
Cycles:
Phosphorous
Cycle
Leaching
Consumption
Precipitation
Plant
uptake
of PO
4
3–
Soil
Sedimentation
Uptake
Plankton
Decomposition
Dissolved PO
4
3–
Runoff
Geologic
uplift
Weathering
of rocks
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Decomposition and Nutrient Cycling Rates
•Decomposers = detritivoresplay a key role in
the general pattern of chemical cycling.
•Rates at which nutrients cycle in different
ecosystems vary greatly, mostly as a result of
differing rates of decomposition.
•The rate of decomposition is controlled by
temperature, moisture, and nutrient availability.
•Rapid decomposition results in relatively low
levels of nutrients in the soil.
Decomposition and Nutrient Cycling Rates
•Decomposers = detritivoresplay a key role in
the general pattern of chemical cycling.
•Rates at which nutrients cycle in different
ecosystems vary greatly, mostly as a result of
differing rates of decomposition.
•The rate of decomposition is controlled by
temperature, moisture, and nutrient availability.
•Rapid decomposition results in relatively low
levels of nutrients in the soil.
How does
temperature
affect litter
decomposition
in an
ecosystem?
Ecosystem typeEXPERIMENT
RESULTS
Arctic
Subarctic
Boreal
Temperate
Grassland
Mountain
P
O
D
J
RQ
K
B,C
E,F
H,I
LNU
S
T
M
G
A
A
80
70
60
50
40
30
20
10
0
–15 –10 –5 0 5 10 15
Mean annual temperature (ºC)
Percent of mass lost B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
temperature
affect litter
decomposition
in an
ecosystem?
Ecosystem typeEXPERIMENT
RESULTS
Arctic
Subarctic
Boreal
Temperate
Grassland
Mountain
P
O
D
J
RQ
K
B,C
E,F
H,I
LNU
S
T
M
G
A
A
80
70
60
50
40
30
20
10
0
–15 –10 –5 0 5 10 15
Mean annual temperature (ºC)
Percent of mass lost B
C
D
E
F
G
H
I
J
K
L
M
N
O
P
Q
R
S
T
U
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Case Study:Nutrient Cycling in the Hubbard
Brook Experimental Forest
•Vegetation strongly regulates nutrient cycling.
•Research projects monitor ecosystem
dynamics over long periods.
•The Hubbard Brook Experimental Forest has
been used to study nutrient cycling in a forest
ecosystem since 1963.
•The research team constructed a dam on the
site to monitor loss of water and minerals.
Case Study:Nutrient Cycling in the Hubbard
Brook Experimental Forest
•Vegetation strongly regulates nutrient cycling.
•Research projects monitor ecosystem
dynamics over long periods.
•The Hubbard Brook Experimental Forest has
been used to study nutrient cycling in a forest
ecosystem since 1963.
•The research team constructed a dam on the
site to monitor loss of water and minerals.
Nutrient
Cycling
in the
Hubbard Brook
Experimental
Forest: an
example of
long-term
ecological
research
1965
(c) Nitrogen in runoff from watersheds
Nitrate concentration in runoff
(mg/L)
(a) Concrete dam
and weir
(b) Clear-cut watershed
1966 1967 1968
Control
Completion of
tree cutting
Deforested
0
1
2
3
4
20
40
60
80
Cycling
in the
Hubbard Brook
Experimental
Forest: an
example of
long-term
ecological
research
1965
(c) Nitrogen in runoff from watersheds
Nitrate concentration in runoff
(mg/L)
(a) Concrete dam
and weir
(b) Clear-cut watershed
1966 1967 1968
Control
Completion of
tree cutting
Deforested
0
1
2
3
4
20
40
60
80
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
•In one experiment, the trees in one valley were cut
down, and the valley was sprayed with herbicides. Net
losses of water and minerals were studied and found
to be greater than in an undisturbed area.
•These results showed how human activity can affect
ecosystems.
•As the human population has grown, our activities
have disrupted the trophic structure, energy flow, and
chemical cycling of many ecosystems.
•In addition to transporting nutrients from one location
to another, humans have added new materials, some
of them toxins, to ecosystems.
•In one experiment, the trees in one valley were cut
down, and the valley was sprayed with herbicides. Net
losses of water and minerals were studied and found
to be greater than in an undisturbed area.
•These results showed how human activity can affect
ecosystems.
•As the human population has grown, our activities
have disrupted the trophic structure, energy flow, and
chemical cycling of many ecosystems.
•In addition to transporting nutrients from one location
to another, humans have added new materials, some
of them toxins, to ecosystems.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Agriculture and Nitrogen Cycling
•The quality of soil varies with the amount of
organic material it contains.
•Agriculture removes from ecosystems nutrients
that would ordinarily be cycled back into the
soil.
•Nitrogen is the main nutrient lost through
agriculture; thus, agriculture greatly affects the
nitrogen cycle.
•Industrially produced fertilizer is typically used
to replace lost nitrogen, but effects on an
ecosystem can be harmful.
Agriculture and Nitrogen Cycling
•The quality of soil varies with the amount of
organic material it contains.
•Agriculture removes from ecosystems nutrients
that would ordinarily be cycled back into the
soil.
•Nitrogen is the main nutrient lost through
agriculture; thus, agriculture greatly affects the
nitrogen cycle.
•Industrially produced fertilizer is typically used
to replace lost nitrogen, but effects on an
ecosystem can be harmful.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Contamination of Aquatic Ecosystems
•Critical loadfor a nutrient is the amount that
plants can absorb without damaging the
ecosystem.
•When excess nutrientsare added to an
ecosystem, the critical load is exceeded.
•Remaining nutrients can contaminate
groundwater as well as freshwater and marine
ecosystems.
•Sewage runoff causescultural eutrophication,
excessive algal growth that can greatly harm
freshwater ecosystems.
Contamination of Aquatic Ecosystems
•Critical loadfor a nutrient is the amount that
plants can absorb without damaging the
ecosystem.
•When excess nutrientsare added to an
ecosystem, the critical load is exceeded.
•Remaining nutrients can contaminate
groundwater as well as freshwater and marine
ecosystems.
•Sewage runoff causescultural eutrophication,
excessive algal growth that can greatly harm
freshwater ecosystems.
The dead zone arising from nitrogen pollution in the
Mississippi basin
Winter Summer
Mississippi basin
Winter Summer
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Acid Precipitation
•Combustion of fossil fuels is the main cause of acid
precipitation.
•North American and European ecosystems downwind
from industrial regions have been damaged by rain
and snow containing nitric and sulfuric acid.
•Acid precipitation changes soil pH andcauses
leaching of calcium and other nutrients.
•Environmental regulations and new technologies have
allowed many developed countries to reduce sulfur
dioxide emissions.
Acid Precipitation
•Combustion of fossil fuels is the main cause of acid
precipitation.
•North American and European ecosystems downwind
from industrial regions have been damaged by rain
and snow containing nitric and sulfuric acid.
•Acid precipitation changes soil pH andcauses
leaching of calcium and other nutrients.
•Environmental regulations and new technologies have
allowed many developed countries to reduce sulfur
dioxide emissions.
Changes in the pH of precipitation at Hubbard Brook
Year
200019951990198519801975197019651960
4.0
4.1
4.2
4.3
4.4
4.5
Year
200019951990198519801975197019651960
4.0
4.1
4.2
4.3
4.4
4.5
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Toxins in the Environment
•Humans release many toxic chemicals, including
synthetics previously unknown to nature. In some
cases, harmful substances persist for long periods in
an ecosystem.
•One reason toxinsare harmful is that they become
more concentrated in successive trophic levels.
•Biological magnificationconcentrates toxins at
higher trophic levels.
•PCBs and many pesticides such as DDT are subject
to biological magnification in ecosystems.
Toxins in the Environment
•Humans release many toxic chemicals, including
synthetics previously unknown to nature. In some
cases, harmful substances persist for long periods in
an ecosystem.
•One reason toxinsare harmful is that they become
more concentrated in successive trophic levels.
•Biological magnificationconcentrates toxins at
higher trophic levels.
•PCBs and many pesticides such as DDT are subject
to biological magnification in ecosystems.
Biological
Magnification
of PCBs in a
Great Lakes
food web
Lake trout
4.83 ppm
Herring
gull eggs
124 ppm
Smelt
1.04 ppm
Phytoplankton
0.025 ppm
Zooplankton
0.123 ppm
Magnification
of PCBs in a
Great Lakes
food web
Lake trout
4.83 ppm
Herring
gull eggs
124 ppm
Smelt
1.04 ppm
Phytoplankton
0.025 ppm
Zooplankton
0.123 ppm
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Greenhouse Gases and Global Warming
•One pressing problem caused by human
activities is the rising level of atmospheric
carbon dioxide.
•Due to the burning of fossil fuels and other
human activities, the concentration of
atmospheric CO
2has been steadily increasing.
Greenhouse Gases and Global Warming
•One pressing problem caused by human
activities is the rising level of atmospheric
carbon dioxide.
•Due to the burning of fossil fuels and other
human activities, the concentration of
atmospheric CO
2has been steadily increasing.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
The Greenhouse Effect and Climate
•CO
2, water vapor, and othergreenhouse gases
reflect infrared radiation back toward Earth; this
is thegreenhouse effect.
•This effect is important for keeping Earth’s
surface at a habitable temperature.
•Increased levelsof atmospheric CO
2are
magnifying the greenhouse effect, which could
cause global warming andclimatic change.
The Greenhouse Effect and Climate
•CO
2, water vapor, and othergreenhouse gases
reflect infrared radiation back toward Earth; this
is thegreenhouse effect.
•This effect is important for keeping Earth’s
surface at a habitable temperature.
•Increased levelsof atmospheric CO
2are
magnifying the greenhouse effect, which could
cause global warming andclimatic change.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
•Increasing concentration of atmospheric CO
2is linked
to increasing global temperature. Northern coniferous
forests and tundra show the strongest effects of global
warming.
•A warming trend would also affect the geographic
distribution of precipitation.
•Global warming can be slowed by reducing energy
needs and converting to renewable sources of energy.
•Stabilizing CO
2emissions will require an international
effort.
•Increasing concentration of atmospheric CO
2is linked
to increasing global temperature. Northern coniferous
forests and tundra show the strongest effects of global
warming.
•A warming trend would also affect the geographic
distribution of precipitation.
•Global warming can be slowed by reducing energy
needs and converting to renewable sources of energy.
•Stabilizing CO
2emissions will require an international
effort.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
Depletion of Atmospheric Ozone
•Life on Earth is protected fromdamaging
effects of UV radiation by a protective layer of
ozone molecules in the atmosphere.
•Satellite studies suggest that the ozone layer
has been gradually thinning since 1975.
•Destruction of atmospheric ozoneprobably
results from chlorine-releasing pollutants such
as CFCs(chloroflorocarbons) produced by
human activity.
Depletion of Atmospheric Ozone
•Life on Earth is protected fromdamaging
effects of UV radiation by a protective layer of
ozone molecules in the atmosphere.
•Satellite studies suggest that the ozone layer
has been gradually thinning since 1975.
•Destruction of atmospheric ozoneprobably
results from chlorine-releasing pollutants such
as CFCs(chloroflorocarbons) produced by
human activity.
How free chlorine in the atmosphere destroys ozone
O
2
Sunlight
Cl
2O
2
Chlorine
Chlorine atom
O
3
O
2
ClO
ClO
O
2
Sunlight
Cl
2O
2
Chlorine
Chlorine atom
O
3
O
2
ClO
ClO
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
•Scientists first described an “ozone hole”over
Antarcticain 1985; it has increased in size as
ozone depletion has increased.
•Ozone depletion causes DNA damagein plants
and poorer phytoplankton growth.
•An international agreement signed in 1987 has
resulted in a decrease in ozone depletion.
•Scientists first described an “ozone hole”over
Antarcticain 1985; it has increased in size as
ozone depletion has increased.
•Ozone depletion causes DNA damagein plants
and poorer phytoplankton growth.
•An international agreement signed in 1987 has
resulted in a decrease in ozone depletion.
Erosion of Earth’s ozone shield
(a) September 1979 (b) September 2006
(a) September 1979 (b) September 2006
Review
Fossilization
Organic
materials
available
as nutrients
Living
organisms,
detritus
Organic
materials
unavailable
as nutrients
Coal, oil,
peat
Burning
of fossil
fuels
Respiration,
decomposition,
excretion
Assimilation,
photosynthesis
Inorganic
materials
available
as nutrients
Inorganic
materials
unavailable
as nutrients
Atmosphere,
soil, water
Minerals
in rocks
Weathering,
erosion
Formation of
sedimentary rock
Fossilization
Organic
materials
available
as nutrients
Living
organisms,
detritus
Organic
materials
unavailable
as nutrients
Coal, oil,
peat
Burning
of fossil
fuels
Respiration,
decomposition,
excretion
Assimilation,
photosynthesis
Inorganic
materials
available
as nutrients
Inorganic
materials
unavailable
as nutrients
Atmosphere,
soil, water
Minerals
in rocks
Weathering,
erosion
Formation of
sedimentary rock
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
You should now be able to:
1.Explain how the first and second laws of
thermodynamics apply to ecosystems.
2.Define and compare gross primary
production, net primary production, and
standing crop.
3.Explain why energy flows but nutrients cycle
within an ecosystem.
4.Explain what factors may limit primary
production in aquatic ecosystems.
You should now be able to:
1.Explain how the first and second laws of
thermodynamics apply to ecosystems.
2.Define and compare gross primary
production, net primary production, and
standing crop.
3.Explain why energy flows but nutrients cycle
within an ecosystem.
4.Explain what factors may limit primary
production in aquatic ecosystems.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
5.Distinguish between the following pairs of
terms: primary and secondary production,
production efficiency and trophic efficiency.
6.Explain why worldwide agriculture could feed
more people if all humans consumed only
plant material.
7.Describe the four nutrient reservoirs and the
processes that transfer the elements between
reservoirs.
5.Distinguish between the following pairs of
terms: primary and secondary production,
production efficiency and trophic efficiency.
6.Explain why worldwide agriculture could feed
more people if all humans consumed only
plant material.
7.Describe the four nutrient reservoirs and the
processes that transfer the elements between
reservoirs.
Copyright © 2008 Pearson Education, Inc., publishing as Pearson Benjamin Cummings
8.Explain why toxic compounds usually have
the greatest effect on top-level carnivores.
9.Describe the causes and consequences of
ozone depletion.
8.Explain why toxic compounds usually have
the greatest effect on top-level carnivores.
9.Describe the causes and consequences of
ozone depletion.
Tags
Categories
GeneralDownload
Download Slideshow Get the original presentation fileQuick Actions
Statistics
- Views 35
- Slides 61
- Age 523 days
Related Slideshows
22
Pray For The Peace Of Jerusalem and You Will Prosper
RodolfoMoralesMarcuc
32 views
26
Don_t_Waste_Your_Life_God.....powerpoint
chalobrido8
35 views
31
VILLASUR_FACTORS_TO_CONSIDER_IN_PLATING_SALAD_10-13.pdf
JaiJai148317
32 views
14
Fertility awareness methods for women in the society
Isaiah47
30 views
35
Chapter 5 Arithmetic Functions Computer Organisation and Architecture
RitikSharma297999
29 views
5
syakira bhasa inggris (1) (1).pptx.......
ourcommunity56
30 views