Transcript ecosystems - Gull Lake Community Schools

ECOSYSTEMS
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All of the organisms living in a community
and the abiotic factors with which they
interact.
“global ecosystem”
Energy flows
Nutrients cycle
Trophic levels = species grouped into feeding
relationships, used to follow energy
transformations through the whole ecosystem
Trophic levels
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Primary producers ; autotrophs , plants
Heterotrophs ; indirectly need photosynthetic output
Primary consumers ; herbivores – directly eat the
plants or algae
Secondary consumers ; carnivores that eat
herbivores
Tertiary consumers ; carnivores that eat other
carnivores
Detritivores/ decomposers ; obtain energy from
detritus ( nonliving organic material)
Decomposition
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Vital role in linking nutrient cycle
Fungi, bacteria, invertebrates and some
vertebrates
Lots of organic matter in things like fallen
leaves that are consumed by crayfish or
worms
Make chemical elements available
Digestive enzymes of fungi make ‘wood’
available to other organisms.
Interdisciplinary ….
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Can’t create or destroy matter
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Nutrients cycle
Can’t create or destroy energy
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Energy flows
(overall) Entropy increases
ENERGY TRANSFORMATIONS
Global energy budget is 1022 joules of solar
energy per day
Production
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Gross primary production = amount of solar
energy that is converted to chemical energy
by photosynthesis per unit time
Net primary production = gross – energy
used by primary producers for respiration.
NPP = GPP – R
Remember that producers (plants and algae)
are doing photosynthesis AND RESPIRATION
in order to grow and develop.
Lab 12 : Dissolved Oxygen
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Oxygen is generated by photosynthesis
The amount of dissolved oxygen can be measured
quantitatively
If one system has more production, their should be
more oxygen
If algae samples are kept in dark, respiration rates
should overcome photosynthesis rates and oxygen
should go down.
The oxygen should show the same trend as the
light…. Other limiting factors ?
N and P also have roles
As does the heat (temperature) associated with the
light source
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Herbaceous plants have a higher ratio of
green stem to leaves and support less tissue
through respiration
Trees/ woody plants have mores stem, trunk
and roots tissue to support through
respiration
BIOMASS = energy per area per time, this is
the weight of plant matter added to the
environment per area per time (dry mass)
g/m2/year ( energy = J/m2/year)
Aquatic Ecosystems
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Limiting factors increase or decrease
Limits to primary productivity
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Light
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More light = more photosynthesis “photic zone”
Only 10% reaches in about 20 m in clear water
Not nec. more productive nearer equator
Nutrients
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Limiting nutrients must be added to cause an increase, these
are actually minimal in surface waters at equator and increase
with depth
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N nitrogen
P phosphorus
Increase without creating a bloom
Fe Iron also of interest in cyanobacteria
Fresh water ecosystems
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Solar radiation
Nutrients
TEMPERATURE
Eutrophication = shift from
phytoplantkon to cyanobacteria, gradual
filling in of lakes at edges and bottom.
Negative if man made/accelerated
because of pollution
Terrestrial Ecosystems
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Water availability/ moisture
Solar energy
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Nutrients
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Seasonal
Dissolved in soil
TEMPERATURE
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Tropical rain forests are warm and wet
Deserts are dry and vary in temperature
Secondary Production
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Amount of chemical energy in the
CONSUMERS food that is converted to
new biomass in a given time period
Grass  cow + manure + CO2 +
methane + growth ….. How much grain
mass became cow mass ?
Usually between 10 - and 20 % (limits
number of trophic levels)
Energy pyramids
Nutrient cycling
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Biogeochemical cycles
Cycling of gases (C, N, O and S) in
atmosphere
Less mobile elements (P, K, Ca, etc.)
usually on a more localized scale
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Absorbed by roots from soil
Returned to area by decomposers in fallen
leaves
Generalized model of cycling
Organic
Available
Living and detritus
Inorganic
Available
Atmosphere, soil
and water
Organic
Unavailable
Coal, oil, peat
Inorganic
Unavailable
minerals
Carbon cycle
Nitrogen cycle
Water cycle
Phosphorus cycle