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The Living World
Nutrient Cycles
Carbon
Water
Nitrogen
Phosphorous
Sulfur
General Nutrient Cycles
Reservoir a
Reservoir b
Organic
materials
available
as nutrients
Organic
materials
unavailable
as nutrients
Living
organisms,
detritus
Coal, oil,
peat
Reservoir c
Reservoir d
Inorganic
materials
available
as nutrients
Inorganic
materials
unavailable
as nutrients
Atmosphere,
soil, water




Minerals
in rocks


Burning of fossil fuels
Weathering, erosion
Sedimentation
Respiration,
decomposition,excretion
Assimilation,
photosynthesis
Fossilization
General Nutrient Cycling
Reservoir a
Organic
materials
available
as nutrients
Living
organisms,
detritus
Assimilation,
photosynthesis
Reservoir b
Organic
materials
unavailable
as nutrients
Fossilization
Coal, oil,
peat
Respiration,
decomposition,
excretion
Burning
of fossil fuels
Reservoir c
Reservoir d
Inorganic
materials
available
as nutrients
Inorganic
materials
unavailable
as nutrients
Atmosphere,
soil, water
Weathering,
erosion
Formation of
sedimentary rock
Minerals
in rocks
Carbon Cycle
Processes: Increase or Decrease?
Cellular Respiration
Photosynthesis
Combustion of Fossil Fuels
Formation of Coral Reefs
Decomposition
Carbon Cycle
Processes: Increase or Decrease?
Cellular Respiration
Photosynthesis
Combustion of Fossil Fuels
Formation of Coral Reefs
Decomposition
Nitrogen Cycle
Nitrogen Cycle Processes
Ammonification
Nitrification
Denitrification
Nitrogen fixation
Assimilation
Decomposition
NH3  NO2NO2-  NO3NOx  N2
N2 NH4+
Proteins  NH4+ or NOx
NH4+ or NO3-  Proteins
Nitrogen Cycle Processes
Ammonification
Nitrification
Denitrification
Nitrogen fixation
Assimilation
Decomposition
NH3  NO2NO2-  NO3NOx  N2
N2 NH4+
Proteins  NH4+ or NOx
NH4+ or NO3-  Proteins
Phosphorous
Cycle
Sources of Phosphorous






Erosion
Mine run off
Fertilizer run off
Poo
Nutrient Upwelling
Decomposition
Impact of Nutrients on Ecosystems
Inorganic
phosphorus
5
4
3
2
1
8
7
6
5
4
3
2
1
0
0
2
4
5
11 30 15 19 21
Station number
Great
Moriches
South Bay
Bay
30
Phytoplankton
(millions of cells per mL)
Phytoplankton
8
7
6
Inorganic phosphorus
(g atoms/L)
Phytoplankton
(millions of cells/mL)
RESULTS Phytoplankton abundance parallels the abundance of phosphorus in the water (a). Nitrogen,
however, is immediately taken up by algae, and no free nitrogen is measured in the coastal waters. The
addition of ammonium (NH4) caused heavy phytoplankton growth in bay water, but the addition of
phosphate (PO43) did not induce algal growth (b).
24
Ammonium enriched
Phosphate enriched
Unenriched control
18
12
6
0
Starting 2
algal
density
Shinnecock
Bay
(a) Phytoplankton biomass and phosphorus concentration
4
5 11 30
Station number
19
(b) Phytoplankton response to nutrient enrichment
Questions: 1) What does the first graph show?
2) Graph #2 – what is the limiting nutrient in the second graph?
Figure 54.6
15
21
Impact of Nutrients on Ecosystems
Inorganic
phosphorus
5
4
3
2
1
8
7
6
5
4
3
2
1
0
0
2
4
5
11 30 15 19 21
Station number
Great
Moriches
South Bay
Bay
30
Phytoplankton
(millions of cells per mL)
Phytoplankton
8
7
6
Inorganic phosphorus
(g atoms/L)
Phytoplankton
(millions of cells/mL)
RESULTS Phytoplankton abundance parallels the abundance of phosphorus in the water (a). Nitrogen,
however, is immediately taken up by algae, and no free nitrogen is measured in the coastal waters. The
addition of ammonium (NH4) caused heavy phytoplankton growth in bay water, but the addition of
phosphate (PO43) did not induce algal growth (b).
24
Ammonium enriched
Phosphate enriched
Unenriched control
18
12
6
0
Shinnecock
Bay
(a) Phytoplankton biomass and phosphorus concentration
Starting 2
algal
density
4
5 11 30
Station number
19
(b) Phytoplankton response to nutrient enrichment
Since adding phosphorus, which was already in rich supply, had no effect on
CONCLUSION
Nannochloris growth, whereas adding nitrogen increased algal density dramatically, researchers
concluded that nitrogen was the nutrient limiting phytoplankton growth in this ecosystem.
Figure 54.6
15
21
Sulfur Cycle
Trophic Levels

List the first four trophic levels and give an example for each in an aquatic
system and in a terrestrial system.
Level
Aquatic
Terrestrial
Trophic Levels

List the first four trophic levels and give an example for each in an aquatic
system and in a terrestrial system.
Level
Primary Producer
Prim. Consumer
Sec. Cons.
Tert. Cons.
Aquatic
Terrestrial
Food Chains and Food Webs
Keystone Species


Dominant and keystone species exert strong
controls on community structure
In general, a small number of species in a
community
Number of species
present
20
With Pisaster (control)
15
10
Without Pisaster (experimental)
5
0
1963 ´64 ´65 ´66 ´67 ´68 ´69 ´70 ´71 ´72 ´73
(a) The sea star Pisaster ochraceous feeds
preferentially on mussels but will
consume other invertebrates.
Figure 53.16a,b
What does the graph show?
Number of species
present
Importance of Keystone Species
20
With Pisaster (control)
15
10
Without Pisaster (experimental)
5
0
1963 ´64 ´65 ´66 ´67 ´68 ´69 ´70 ´71 ´72 ´73
(a) The sea star Pisaster ochraceous feeds
preferentially on mussels but will
consume other invertebrates.
Figure 53.16a,b
(b) When Pisaster was removed from an intertidal zone,
mussels eventually took over the rock face and eliminated
most other invertebrates and algae. In a control area from
which Pisaster was not removed, there was little change
in species diversity.
Observation of sea otter populations and their predation
Otter
number (%
max. count)
100
80
60
40
20
Grams per
0.25 m2
0
(a) Sea otter abundance
400
300
200
Number per
0.25 m2
100
0
(b) Sea urchin biomass
10
8
6
4
2
0
1972
Figure 53.17
Food chain before
killer whale involvement in chain
1985
(c) Total kelp density
1989
Year
1993 1997
Food chain after killer
whales started preying
on otters
Ecosystem “Engineers”
(Engineering and Foundation
Species)

Some organisms exert their influence
–
By causing physical changes in the environment
that affect community structure
Beaver dams
Can transform landscapes on a very large scale
(engineering)
Figure 53.18
Foundation species act as facilitators
–
That have positive effects on the survival and
reproduction of some of the other species in the
community
Number of plant species
8
6
4
2
0
Figure 53.19
Salt marsh with Juncus
(foreground)
With
Juncus
Without
Juncus
Conditions
Ecosystem Dynamics
Tertiary
consumers
Microorganisms
and other
detritivores
Detritus
Secondary
consumers
Primary consumers
Primary producers
Heat
Key
Chemical cycling
Energy flow
Figure 54.2
Sun
Trophic Level Pyramids
5
4
3
2
1
Grass
Secondary Consumer
Tertiary Consumer
Decomposer
Vole
Grasshopper
Producer
Snake
Primary Consumer
Trophic Level Pyramids
5
4
3
2
1
Grass - 1
Secondary Consumer - 3
Tertiary Consumer - 4
Decomposer - 5
Bird (insectivore) - 3
Grasshopper – 2
Producer - 1
Snake - 4
Primary Consumer - 2
Trophic Efficiency and Ecological
Pyramids

Trophic efficiency
–
–
–
Is the percentage of production transferred from
one trophic level to the next
Usually ranges from 5% to 20%
Average = 10%
Pyramids of Production

This loss of energy with each transfer in a food chain
–
Can be represented by a pyramid of net production
Tertiary
consumers
Secondary
consumers
Primary
consumers
Primary
producers
Figure 54.11
10 J
100 J
1,000 J
10,000 J
1,000,000 J of sunlight
Pyramids of Biomass

One important ecological consequence of
low trophic efficiencies
–
Can be represented in a biomass pyramid
Most biomass pyramids
Show a sharp decrease at successively higher
trophic levels
Trophic level
Dry weight
(g/m2)
Tertiary consumers
1.5
Secondary consumers
11
Primary consumers
Primary producers
(a) Most biomass pyramids show a sharp decrease in biomass at
successively higher trophic levels, as illustrated by data from
a bog at Silver Springs, Florida.
Figure 54.12a
37
809
Certain aquatic ecosystems
Have inverted biomass pyramids
Trophic level
Dry weight
(g/m2)
Primary consumers (zooplankton)
21
Primary producers (phytoplankton)
4
(b) Why is this pyramid inverted?
Figire 54.12b
Certain aquatic ecosystems
Have inverted biomass pyramids
Trophic level
Dry weight
(g/m2)
Primary consumers (zooplankton)
21
Primary producers (phytoplankton)
4
(b) In some aquatic ecosystems, such as the English Channel,
a small standing crop of primary producers (phytoplankton)
supports a larger standing crop of primary consumers (zooplankton).
Figire 54.12b
Pyramids of Numbers
Trophic level
Tertiary consumers
Number of
individual organisms
3
Secondary consumers
354,904
Primary consumers
708,624
Primary producers
Figure 54.13
5,842,424
PBJ and Turkey

The dynamics of energy flow through ecosystems
–

Have important implications for the human population
Eating meat
–
Is a relatively inefficient way of tapping photosynthetic
production
Worldwide agriculture could successfully feed many more
people
If humans all fed more efficiently, eating only plant material
Trophic level
Secondary
consumers
Primary
consumers
Primary
producers
Figure 54.14
Biomagnification – reverse of other
ecological pyramids
Bioaccumulation vs. Biomagnification
Bioaccumulation:
- toxins accumulate in tissues of organism –
may or may not be passed to higher trophic
levels
Biomagnification:
- increase of the toxic levels as they are
passed up trophic levels
GPP and NPP


Gross Primary Productivity – total increase in
biomass
Net Primary Productivity – change in
biomass over a period of time (only the
difference) – this is what is passed to the
next trophic level
NPP of Various Ecosystems
Open ocean
Continental shelf
Estuary
5.2
0.3
0.1
0.1
Algal beds and reefs
Upwelling zones
Extreme desert, rock, sand, ice
4.7
Desert and semidesert scrub
Tropical rain forest
3.5
3.3
2.9
2.7
Savanna
Cultivated land
Boreal forest (taiga)
1.6
Tropical seasonal forest
Temperate deciduous forest
1.5
1.3
1.0
0.4
Temperate evergreen forest
Swamp and marsh
Lake and stream
Marine
10
3.0
90
0.04
0.9
2,200
22
900
7.9
9.1
600
9.6
800
600
700
5.4
3.5
0.6
140
1,600
7.1
1,200
1,300
4.9
3.8
2.3
0.3
2,000
250
20
30
40
(a) Percentage of Earth’s
surface area
50
60
0
500 1,000 1,500 2,000 2,500
(b) Average net primary
production (g/m2/yr)
Terrestrial
Freshwater (on continents)
0.9
0.1
500
0.4
0
1.2
2,500
1.7
Tundra
24.4
5.6
1,500
2.4
1.8
Temperate grassland
Woodland and shrubland
Key
125
360
65.0
Figure 54.4a–c
0
5
10
15
20
(c) Percentage of Earth’s net
primary production
25
Climate and Terrestrial Biomes
Temperate grassland
Desert
Tropical forest
Annual mean temperature (ºC)
30
Temperate
broadleaf
forest
15
Coniferous
forest
0
Arctic and
alpine
tundra
15
100
200
300
400
Annual mean precipitation (cm)
Overlapping Areas of Biomes = ECOTONE
The distribution of major terrestrial biomes
30N
Tropic of
Cancer
Equator
Tropic of
Capricorn
30S
Key
Tropical forest
Savanna
Figure 50.19
Desert
Chaparral
Tundra
Temperate grassland
High mountains
Temperate broadleaf forest
Polar ice
Coniferous forest
Tropical Rain forest
TROPICAL FOREST
Figure 50.20
A tropical rain forest in Borneo
Tropical Rain Forest
Rainfall: 200 – 400 cm/year
Temperature: 25 – 29 oC
Vegetation: Stratification, dense canopy, broadleaf
evergreen trees
Animals: High animal diversity, usually smaller and
adapted for life in canopy
Seasonal Variations: Little to none
Other Characteristics: Nutrient poor soil, high rate of
decomposition and turn over, extremely high
biodiversity
Desert
DESERT
Figure 50.20 The Sonoran Desert in southern Arizona
Desert
Rainfall: Less than 30 cm/year
Temperature: Wide variation both seasonally and daily
(-30 to 50 oC)
Vegetation: Low, scattered, deeply rooted succulents
(Cacti), dense root mats to absorb water, adapted to
heat and low water
Animals: reptiles, insects, many nocturnal
Seasonal Variations: some have short wet periods
Savanna
SAVANNA
Figure 50.20
A typical savanna in Kenya
Savanna
Rainfall: 76 – 150 cm/year
Temperature: Continually warm, 24 – 29 oC
Vegetation: Scattered trees (acacia), wide expanse of
grasses, adapted to fires, deep roots
Animals: Hoofed mammals, zebras, giraffe, lions,
hyenas
Seasonal Variations: Seasonal Drought
Other Characteristics: Frequent fires, location of the
LION KING
Chaparral
CHAPARRAL
Figure 50.20
An area of chaparral in California
Chaparral
Rainfall: 30 – 50 cm
Temperature: Fall, Winter, Spring  10 – 12 oC,
Summer 30 oC
Vegetation: tough evergreen woody shrubs and small
trees adapted to seasonal fires
Animals: Deer, goats, many small mammals,
amphibians, birds and reptiles
Seasonal Variations: Summers are hot and dry, fall,
winter and spring are cool and rainy
Temperate grassland
TEMPERATE GRASSLAND
Figure 50.20
Sheyenne National Grassland in North Dakota
Temperate Grassland
Rainfall: Dry winters, Wet summers – 30 to 100 cm
Temperature: Cold Winters (-10 oC), Hot summers (30
oC)
Vegetation: ummm….Grass
Animals: Large Grazers (buffalo), prairie dogs
Seasonal Variations: dry winters, wet summers
Coniferous (Boreal) Forest or Taiga
CONIFEROUS FOREST
Rocky Mountain National Park in Colorado
Figure 50.20
Coniferous (Boreal) Forest or Taiga
Rainfall: 30 – 70 cm with periodic drought some may receive up to
300 cm (Pacific North West)
Temperature: Cold, long winters (-70 oC in Siberia), summers
may be hot (30 oC)
Vegetation: Cone bearing trees (pine, spruce, fir, hemlock),
conical shape helps snow fall off so branches don’t break
Animals: Moose, brown bears, Siberian tigers, lots of insects
during summer
Seasonal Variations: Cold, harsh winters, warm summers
Temperate broadleaf forest
TEMPERATE BROADLEAF FOREST
Figure 50.20
Great Smoky Mountains National Park in North Carolina
Temperate broadleaf forest
Rainfall: 70 – 200 cm
Temperature: 0 oC (winter) to 30+ oC (summer)
Vegetation: Broadleaf Deciduous Trees (drop leaves in fall to
prevent water loss in winter), conifers, shrubs and various
grasses and herbaceous plants
Animals: Black bear, deer, squirrels, snakes, birds (migratory and
permanent), insects
Seasonal Variations: Distinct seasons of fall, winter, spring and
summer
Other: You live here
Temperate Rainforest
Temperate Rainforest
Rainfall: More than 125 cm, lots of fog
Temperature: Small amount of seasonal variation ( 3 – 18 oC)–
mild winters, cool summers
Vegetation: Conifers, lots of lichens and epiphytic plants
Animals: Squirrels, mule deer, elk, birds, amphibians and reptiles
Seasonal Variations: Mild differences in season due to location
near coasts
Other: Low nutrient turnover due to low temperatures. Results in a
high accumulation of biological detritus on forest floor
Tundra
TUNDRA
Figure 50.20
Denali National Park, Alaska, in autumn
Tundra
Rainfall: 20 – 60 cm
Temperature: Long cold winters (-30 oC), Short cool summers (10
oC)
Vegetation: Herbaceous (non-woody), dwarf shrubs and trees,
lichens, moss, grasses
Animals: Ox, caribou, reindeer, Santa Claus, Bears, wolves,
foxes, lots of insects in summer
Seasonal Variations:
OTHER: Contains permanent layer of frozen soil call
PERMAFROST
Evolution

Driving forces:
–
–
–
Genetic variation
Competition for resources
Survival of the Fittest
Microevolution vs. Macroevolution
Species Interactions

A biological community
–
Is an assemblage of populations of various
species living close enough for potential
interaction


A community’s interactions include competition,
predation, herbivory, symbiosis, and disease
Populations are linked by interspecific interactions
–
That affect the survival and reproduction of the species
engaged in the interaction
Table 53.1
Competition

Strong competition can lead to competitive
exclusion
–
The local elimination of one of the two competing
species
The Competitive Exclusion
Principle

The competitive exclusion principle
–
States that two species competing for the same
limiting resources cannot coexist in the same
place
Ecological Niches

The ecological niche
–
Is the total of an organism’s use of the biotic and
abiotic resources in its environment
EXPERIMENT
Ecologist Joseph Connell studied two barnacle
speciesBalanus balanoides and Chthamalus stellatus that have a
stratified distribution on rocks along the coast of Scotland.
RESULTS
When Connell removed Balanus from the lower
strata, the Chthamalus population spread into that area.
High tide
High tide
Chthamalus
Balanus
Chthamalus
realized niche
Chthamalus
fundamental niche
Balanus
realized niche
Ocean
Figure 53.2
Low tide
In nature, Balanus fails to survive high on the rocks because it is
unable to resist desiccation (drying out) during low tides. Its realized
niche is therefore similar to its fundamental niche. In contrast,
Chthamalus is usually concentrated on the upper strata of rocks. To
determine the fundamental of niche of Chthamalus, Connell removed
Balanus from the lower strata.
Ocean
Low tide
CONCLUSION
The spread of Chthamalus when Balanus was
removed indicates that competitive exclusion makes the realized
niche of Chthamalus much smaller than its fundamental niche.
Results of Competition – more specific
niches

As a result of competition
–

A species’ fundamental niche may be different from its realized
niche
Resource partitioning is the differentiation of niches
–
That enables similar species to coexist in a community
Resource Partitioning
A. insolitus
usually perches
on shady branches.
A. ricordii
A. distichus perches
on fence posts and
other sunny
surfaces.
A. insolitus
A. alinigar
A. christophei
A. distichus
A. cybotes
A. etheridgei
Figure 53.3
Species Interactions





Predation
Predator, Prey Plant Connection
Competition
Herbivory
Parasitism
–
–


Disease
Mutualism
–
–

Um….gross
Even nastier
Ants and caterpillars
Goby and shrimp
Commensalism
Predation

Predation refers to an interaction
–
Where one species, the predator, kills and eats
the other, the prey
EPIC PREDATION

Feeding adaptations of predators include
–

Claws, teeth, fangs, stingers, and poison
Animals also display
–
A great variety of defensive adaptations
Cryptic coloration, or camouflage
–
Figure 53.5
Makes prey difficult to spot
Aposematic coloration
Figure 53.6
Batesian mimicry
(b) Green parrot snake
Figure 53.7a, b
(a) Hawkmoth larva
Müllerian mimicry
(a) Cuckoo bee
Figure 53.8a, b
(b) Yellow jacket
Herbivory

Herbivory, the process in which an herbivore
eats parts of a plant
–
Has led to the evolution of plant mechanical and
chemical defenses and consequent adaptations
by herbivores
Parasitism

In parasitism, one organism, the parasite
–
Derives its nourishment from another organism,
its host, which is harmed in the process
Disease

The effects of disease on populations and
communities
–
Is similar to that of parasites
Mutualism
Figure 53.9

Commensal interactions have been difficult
to document in nature
–
Because any close association between species
likely affects both species
Interspecific Interactions and
Adaptation

Evidence for coevolution
–
Which involves reciprocal genetic change by
interacting populations, is scarce
Species Diversity

The species diversity of a community
–
–
Is the variety of different kinds of organisms that
make up the community
Has two components

Species richness
–

Is the total number of different species in the
community
Relative abundance
–
Is the proportion each species represents of the total
individuals in the community
Two different communities
Can have the same species richness, but a different
relative abundance
A
B
C
D
Figure 53.11
A: 25%
Community 1
B: 25%
C: 25%
D: 25%
A: 80%
Community 2
B: 5%
C: 5%
D: 10%
Ecological Succession

Ecological succession
–
Is the sequence of community and ecosystem
changes after a disturbance

Primary succession
–

Occurs where no soil exists when succession begins
Secondary succession
–
Begins in an area where soil remains after a
disturbance