Download ecosystem stability

Mk. Analisis Ekosistem
KARAKTERISTIK
KETAHANAN
EKOSISTEM
Diabstraksikan: smno.psdl.pdkl.ppsub.2012/13
BIODIVERSITAS
1. Biodiversity = the amount of biological or living diversity per
unit area. It includes the concepts of species diversity, genetic
diversity and habitat diversity
2. Genetic diversity = the range of genetic material present in a
gene pool or population of a species
3. Species diversity = variety among species per unit area.
Includes both the number of species present and their
abundance.
4. Habitat diversity = The range of different habitats or number of
ecological niches per unit area in an ecosystem, community or
biome. Conservation of habitat diversity usually leads to
conservation of species and genetic diversity
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BIODIVERSITAS:
SPESIES & PROSES
• Is key to the overall function of earth
• In general Diversity = Stability
• Biodiversity is
– Nature’s insurance policy against change
– The source of all natural capital for human use
– The way chemical materials are cycled and purified
– The end result of millions of years of evolution and
irreplaceable
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BIODIVERSITAS
1. Richness: The number of species per sample is a
measure of richness.
 The more species present in a sample, the “richer”
the sample.
2. Evenness: A measure of the relative abundance of
the different species making up the richness of an
area.
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Quantifiying this Diversity –
Simpson’s Index
D = N (N – 1)
∑ n (n – 1)
• Where
D = diversity index
N = total # of organisms of all species
n = # of individuals of particular species
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Quantifiying this Diversity –
Simpson’s Index
• High values of “D” suggests a stable and ancient site
• A low value of “D” could suggest pollution, recent
colonization, or agricultural management
• Index normally used in studies of vegetation but can be
applied to comparisons of diversity of any species
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How does diversity exist?
• Natural Selection = survival of the fittest
• Fitness = a measure of reproductive success
• If all individuals are variable
• And populations produce large numbers of offspring without
increase in population size
• And resources are limited
• And traits are heritable
• Then those individuals who are best adapted to the
environment will survive and pass on their genes
• Gradually the gene frequency in the population will represent
Diunduh
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more
ofdari:
these
“fit” individuals
SELEKSI ALAMIAH
• Environmental Pressures select for some genotypes over
others
• Alleles resulting in a beneficial trait will become more
common
• Heritable traits that increase survival chances are called
adaptations
• There are many niches or habitats and roles available in
the environment
• As populations adapt they fill new niches and over time
may develop into new species
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Speciation
• Certain circumstances lead to the production of new species
through natural selection
• Most common mechanism has 2 phases  geographic followed
by reproductive isolation
1. Geographic isolation  groups of a population of the same
species are isolated for long periods
– A group may migrate in search of food to an area with different
environmental conditions
– Populations may be separated by a physical barrier (mountain range,
river, road)
– Catastrophic change by volcano eruption or earthquake
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19/12/2012
– ADiunduh
few individuals
carried away by wind or water to new area
Speciation 2
2. Reproductive Isolation  mutation and natural selection
operate independently on the 2 populations to change allele
frequencies = divergence
• If divergence continues long enough genetic differences may
prohibit (1) interbreeding between populations and/or (2)
production of viable, fertile offspring
• One species has become 2 through divergent evolution
• For most species this would take millions of years
• Difficult to document & prove this process
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Northern population
Arctic Fox
Early fox
population
Spreads
northward
and
southward
and
separates
Adapted to cold
through heavier
fur, short ears,
short legs, short
nose. White fur
matches snow
for camouflage.
Different environmental
conditions lead to different
selective pressures and evolution
into two different species.
Southern population
Gray Fox
Adapted to heat
through lightweight
fur and long ears,
legs, and nose, which
give off more heat.
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Consequences of Plate Activity
• Speciation processes rely on physical separation of
organisms
• Plate techtonics
– can lead to separation of gene pools – mountain
ranges form, faults separating land masses
– Can link species and land areas e.g. land bridges
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Consequences of Plate Activity II
• Plate techtonics generates new habitats
– Island chains over hotspots – Hawaii
– Mountain habitats – Himalayan mountains – also
associated effects on surrounding areas
– Hydrothermal vent communities
– Changes climate on land masses – continents drift into
new climate zones  e.g. antarctica was once covered
by tropical rainforest now barren polar ice fields
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1. Succession effects Diversity
• Succession – gradual establishment or reestablishment of
ecosystems over time
• Pioneer species  Climax species
– Low diversity at first, few species can tolerate harsh conditions (r
selected species)
– Most diverse in middle of succession, slower growing species start
to fill in
– Low diversity at the end, climax species often strongest
competitors (K selected species)
• Diversity is a function of disturbance  intermediate
disturbance hypothesis
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Lichens
and mosses
Exposed
rocks
Small herbs
and shrubs
Heath mat
Jack pine,
black spruce,
and aspen
Balsam fir,
paper birch, and
white spruce
climax community
Time
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Species diversity
0
100
Percentage disturbance
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2. Habitat diversity influences species &
genetic diversity
• More complex areas (more diverse habitats) often
have higher species & genetic diversity
• Ex. Tropical rainforest & Coral reef
• In both cases, high degree of structural / spatial
complexity
• Promotes coexistence by niche partitioning &
diversification
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Harpy
eagle
Blue and
gold macaw
Ocelot
Producer
to primary
consumer
Primary
to secondary
consumer
Squirrel
monkeys
Climbing
monstera palm
Katydid
Slaty-tailed
trogon
Green tree snake
Secondary to
higher-level
consumer
Tree frog
All producers and
consumers to
decomposers
Ants
Bromeliad
Fungi
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Bacteria
45
Emergent
layer
Harpy
eagle
40
35
Toco
toucan
Canopy
30
Height
(meters)
25
20
Understory
Wooly
opossum
15
10
Brazilian
tapir
5
Black-crowned
antpitta
0
Shrub layer
Ground
Ground
layerlayer
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Complex ecosystems with a variety of nutrient & energy
pathways provides stability
• Energy is key to the function of all ecosystems
• Biogeochemical cycles recycle necessary materials
through system
• More pathways for energy & matter = more stable
• Insurance against natural or human changes
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Human activities
• Modify succession by adding disturbance
• Logging, Grazing, Burning – all prevent natural
successional processes
• Fragmenting habitats by development
• Isolate populations  more likely to get diseases,
succumb to local disturbances
• We simplify ecosystems  tall grass prairie
converted to wheat farms  more vulnerable
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Cleared plots
for grazing
Highway
Cleared plots
for agriculture
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Any ecosystem’s capacity to
survive change may
depend on its diversity,
resilience, and inertia
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ECOSYSTEM
STABILITY
STABILITAS EKOSISTEM
1. The vast majority of natural ecosystems experience regular
environmental change, or disturbances.
2. Most ecologists describe ecosystem stability as the ability of an
ecosystem to maintain its structure and function over long periods of
time and despite disturbances.
3. Ecosystem structure includes physical and geological structures of the
landscape, the number and diversity of species present, the population
sizes of those species, and the ways in which these populations interact.
4. Ecosystem function refers to processes such as water and nutrient
cycling and biomass productivity that the ecosystem provides.
. Sumber: www.aisd.net/aisd/Portals/73/.../12F%20Ecosystem%20Stability.ppt ………… diunduh 19/12/2012
RESISTENSI & RESILIENSI
1. There are two main components to ecosystem stability:
resistance and resilience.
2. An ecosystem displays resistance if keeps its structure and
continues normal functions even when environmental
conditions change.
3. An ecosystem displays resilience if, following a disturbance, it
eventually regains its normal structure and function.
. Sumber: www.aisd.net/aisd/Portals/73/.../12F%20Ecosystem%20Stability.ppt ………… diunduh 19/12/2012
STABILITAS EKOSISTEM
1. Ecosystems that show a high degree of stability may have
different combinations of resistance and resilience.
2. Research has shown that species diversity is often the key to
both ecosystem resistance and resilience.
3. An ecosystem rich in biodiversity will likely be more stable
than one whose biodiversity is low.
Infer If an ecosystem has low biodiversity, is it more or less
stable than an ecosystem of high biodiversity?
. Sumber: www.aisd.net/aisd/Portals/73/.../12F%20Ecosystem%20Stability.ppt ………… diunduh 19/12/2012
HOW DOES ENVIRONMENTAL CHANGE AFFECT
ECOSYSTEM STABILITY?
1. Communities respond to environmental change in ways
that reflect the responses of the species and populations
in the community.
2. Species respond to environmental change in ways that
enable them to maintain homeostasis.
3. Populations respond in ways that reflect the success or
failure of members of the population to survive and
reproduce.
. Sumber: www.aisd.net/aisd/Portals/73/.../12F%20Ecosystem%20Stability.ppt ………… diunduh 19/12/2012
STABILITAS EKOSISTEM
• Changing environmental conditions can cause the decline
of local biodiversity. If this happens, an ecosystem’s
resistance and/or resilience may decline. The end result is
that the ecosystem loses stability.
• Ecosystems that are less stable may not be able to respond
to a normal environmental disturbance, which may
damage ecosystem structure, ecosystem function, or both.
. Sumber: www.aisd.net/aisd/Portals/73/.../12F%20Ecosystem%20Stability.ppt ………… diunduh 19/12/2012
How does natural environmental change affect
ecosystem stability?
• Fires, heavy storms, and natural climate change can cause
major changes in local populations of plants and animals.
• A decline in natural biodiversity can make an ecosystem less
stable.
Apply Concepts
What is one example of a local natural environmental
change? How did it impact ecosystem stability?
. Sumber: www.aisd.net/aisd/Portals/73/.../12F%20Ecosystem%20Stability.ppt ………… diunduh 19/12/2012
How does environmental change caused by human
actions affect ecosystem stability?
1. Humans affect ecosystem stability in many ways, including
habitat loss, introduction of nonnative species, release of
pollution into food webs, and contribution to climate change.
2. Ecosystems are frequently destroyed for agricultural activity
and
urban development. Clearing patches of habitat can split
ecosystems into pieces, a process called habitat
fragmentation.
. Sumber: www.aisd.net/aisd/Portals/73/.../12F%20Ecosystem%20Stability.ppt ………… diunduh 19/12/2012
STABILITAS EKOSISTEM
• Remaining pieces of habitat
become habitat “islands”
surrounded by a different
habitat. The smaller a habitat
island is, the fewer species can
live there, and the smaller
their populations can be.
Predict
Sea otters, a keystone
species, eat sea urchins,
which in turn eat kelp. In
the 1990s, sea otter
populations off the coast of
Alaska declined because
orcas ate large numbers of
otters. What effect did this
have on the sea otters’
ecosystem?
• A keystone species is one that
has a strong and/or widereaching impact on a
community’s stability. If a
keystone species declines in
number, the ecosystem
. Sumber: www.aisd.net/aisd/Portals/73/.../12F%20Ecosystem%20Stability.ppt
………… diunduh 19/12/2012
becomes
much less stable.
STABILITAS EKOSISTEM
1. Humans sometimes introduce organisms into a new
habitat, where
it can become invasive and threaten biodiversity and
ecosystem structure.
2. An invasive species is a nonnative species that spreads
widely in a community. Nonnative species become
invasive if their new surroundings lack natural population
checks such as predators or competitors.
3. Invasive species usually cause local native biodiversity to
decline and therefore affect ecosystem stability.
. Sumber: www.aisd.net/aisd/Portals/73/.../12F%20Ecosystem%20Stability.ppt ………… diunduh 19/12/2012
STABILITAS EKOSISTEM
• Many pollutants, including pesticides and acid rain, impact
plant and animal populations. These changes, in turn, threaten
biodiversity.
• Organisms are adapted to their environments and have
specific tolerance ranges to conditions such as temperature. If
conditions change beyond an organism’s tolerance, the
organism must move to another location or face extinction.
• Increases in Earth’s average temperatures could affect
ecosystem structures and functions.
• Scientists are not yet sure how predicted changes in global
climate within the next several decades will affect ecosystem
stability worldwide.
. Sumber: www.aisd.net/aisd/Portals/73/.../12F%20Ecosystem%20Stability.ppt ………… diunduh 19/12/2012
ECOSYSTEM
PRODUCTIVITY
PRODUKTIVITAS EKOSISTEM
Food webs, food chains, pyramids – you can also look at
ecosystems through their productivity.
Productivity is the rate at which chemical energy is
produced in an ecosystem – expressed as ‘gram of
organic matter per square metre per year’
. Sumber: lynclarkson.wikispaces.com/.../4.+ECOSYSTEMS+DIFER+IN+...………… diunduh 19/12/2012
PRODUKTIVITAS PRIMER
EKOSISTEM
 1.Gross primary productivity (GPP) is the rate at which an
ecosystem's producers convert solar energy into chemical
energy as biomass.
 2. Net primary productivity (NPP) is the rate at which energy
for use by consumers is stored in new biomass.
 NPP = GPP – R [rate at which producers use biomass]
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PRODUKTIVITAS EKOSISTEM
 Generally ecosystems with the highest net productivity are those with the
greatest accumulated producer biomass
More
 The higher the net primary production of an ecosystem, chemi
the more food is
available for consumer organisms and the greater the biomass of
More
consumers living in that ecosystem.
cal
produ
More
energ
cer
photos
y
biom
ynthesi
stored
ass
s
in
organi
. Sumber: lynclarkson.wikispaces.com/.../4.+ECOSYSTEMS+DIFER+IN+...………… diunduh 19/12/2012
WHY DO PRODUCTION RATES DIFFER?
1. Why does a desert ecosystem have a lower
productivity than a tropical rainforest?
2. What affects do temperature and hours of
sunlight have on productivity?
3. List some limiting factors for ecosystems?
4. Explain why Australia does not have rich fishing
grounds near its coast.
. Sumber: lynclarkson.wikispaces.com/.../4.+ECOSYSTEMS+DIFER+IN+...………… diunduh 19/12/2012
AN ECOSYSTEM IN DARKNESS
1.
2.
3.
4.
5.
If light is needed for photosynthesis, but does not penetrate to the depths of
the ocean, how does a consumer in ocean darkness feed?
Explain how producers can exist in the dark depths of the ocean.
Explain the difference between photosynthetic organisms and chemosynthetic
organisms.
What is the energy source for photosynthetic organisms? What is the waste
product?
What is the energy source for chemosynthetic organisms? What is the waste
product?
. Sumber: lynclarkson.wikispaces.com/.../4.+ECOSYSTEMS+DIFER+IN+...………… diunduh 19/12/2012
KEY ENERGY PROCESSES
•
Photosynthesis: use of chlorophyll. Energy storing process.
–
•
Cellular Respiration:
–
–
•
6 CO2 + 6 H2O + solar energy  C6H12O6 + 6 O2
Aerobic Respiration: energy releasing process.
C6H12O6 + 6 O2  6CO2 + 6 H2O + energy (ATP)
Anaerobic Respiration
–
Ex. Fermentation: energy releasing process used by yeast and
bacteria
. Sumber: lynclarkson.wikispaces.com/.../4.+ECOSYSTEMS+DIFER+IN+...………… diunduh 19/12/2012
PRIMARY PRODUCTION AND ENERGY FLOW
ENERGY FLOWS:
solar (or nuclear)
input
heat output
NUTRIENTS
RECYCLE:
mass
conservation
inorganic ↔
organic
. Sumber: www2.yk.psu.edu/~mph13/EnergyFlow.18.ppt...………… diunduh 19/12/2012
TINGKAT TROFIK
• Trophic Level: Position in a food web determined by number of
energy transfers from primary producers to current level:
–
–
–
–
Primary producers occupy first level.
Primary consumers occupy second level.
Secondary consumers occupy third level.
Tertiary consumers occupy fourth level.
. Sumber: www2.yk.psu.edu/~mph13/EnergyFlow.18.ppt...………… diunduh 19/12/2012
PRODUSEN – KONSUMEN
. Sumber: www2.yk.psu.edu/~mph13/EnergyFlow.18.ppt...………… diunduh 19/12/2012
PRODUKSI PRIMER
• Primary production: Fixation of energy by
autotrophs in an ecosystem.
– Rate of primary production: Amount of energy fixed
over a given period of time.
• Gross primary production: Total amount of energy fixed
by autotrophs.
• Net primary production: Amount of energy leftover after
autotrophs have met their metabolic needs.
. Sumber: www2.yk.psu.edu/~mph13/EnergyFlow.18.ppt...………… diunduh 19/12/2012
KONTROL
PRODUKSI PRIMER
• Bottom-Up Controls
– Influences of physical and chemical factors of an ecosystem.
• Top-Down Controls
– Influences of consumers.
. Sumber: www2.yk.psu.edu/~mph13/EnergyFlow.18.ppt...………… diunduh 19/12/2012
Actual Evapotranspiration and Terrestrial
Primary Production
• Rosenzweig estimated influence of moisture and
temperature on rates of primary production by plotting
relationship between annual net primary production
and annual actual evapotranspiration (AET).
– AET: Annual amount of water that evaporates and transpires
off a landscape.
• Cold dry ecosystems tend to have low AET.
. Sumber: www2.yk.psu.edu/~mph13/EnergyFlow.18.ppt...………… diunduh 19/12/2012
Evapotranspiration & Terrestrial Primary Production
. Sumber: www2.yk.psu.edu/~mph13/EnergyFlow.18.ppt...………… diunduh 19/12/2012
PRODUKSI PRIMER NETO
. Sumber: www2.yk.psu.edu/~mph13/EnergyFlow.18.ppt...………… diunduh 19/12/2012
PRODUKSI PRIMER & KESUBURAN TANAH
• Significant variation in terrestrial primary production can be
explained by differences in soil fertility.
– Shaver and Chapin found arctic net primary production was twice as
high on fertilized plots as unfertilized plots.
– Bowman suggested N is main nutrient limiting net primary production
in a dry tundra meadow, and N and P jointly limit production in a wet
meadow.
. Sumber: www2.yk.psu.edu/~mph13/EnergyFlow.18.ppt...………… diunduh 19/12/2012
PRODUKSI PRIMER NETO
. Sumber: www2.yk.psu.edu/~mph13/EnergyFlow.18.ppt...………… diunduh 19/12/2012
PRODUKSI PRIMER
. Sumber: www2.yk.psu.edu/~mph13/EnergyFlow.18.ppt...………… diunduh 19/12/2012
POLA PRODUKSI PRIMER AKUATIK
• Several studies have found quantitative relationship
between phosphorus and freshwater phytoplankton
biomass.
• Several studies support generalization that nutrient
availability controls rate of primary production in
freshwater ecosystems.
. Sumber: www2.yk.psu.edu/~mph13/EnergyFlow.18.ppt...………… diunduh 19/12/2012
PRODUKSI PRIMER BIOMASA ALGAE
. Sumber: www2.yk.psu.edu/~mph13/EnergyFlow.18.ppt...………… diunduh 19/12/2012
PRODUKSI PRIMER
DANAU
Carpenter proposed piscivores and planktivorous fish can
cause significant deviations in primary productivity.
– Carpenter and Kitchell proposed the influence of consumers
on lake primary productivity propagate through food webs.
• Trophic Cascade Hypothesis
. Sumber: www2.yk.psu.edu/~mph13/EnergyFlow.18.ppt...………… diunduh 19/12/2012
PRODUKSI PRIMER DANAU
. Sumber: www2.yk.psu.edu/~mph13/EnergyFlow.18.ppt...………… diunduh 19/12/2012
PRODUKSI PRIMER DANAU
. Sumber: www2.yk.psu.edu/~mph13/EnergyFlow.18.ppt...………… diunduh 19/12/2012
PRODUKSI PRIMER DANAU
. Sumber: www2.yk.psu.edu/~mph13/EnergyFlow.18.ppt...………… diunduh 19/12/2012