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ECOSYSTEMS
What is
missing
from
this
food
chain?
detritivores
In what way
is this food
web more
realistic
than the
food chain?
The food web
incorporates
consumers
that feed at
multiple
trophic levels
Primary Producers
Who
are the primary producers of
most terrestrial ecosystems?
Plants
Who are the primary producers of
most aquatic ecosystems?
Microscopic algae and bacteria
(phytoplankton), and
multicellular algae and aquatic
plants.
Consumers
Herbivores
- primary consumers
Carnivores - secondary consumers
Omnivores - can feed at multiple
trophic levels
Decomposers
What organisms are decomposers
in most ecosystems?
Fungi and Bacteria
What do the decomposers do?
Primary Productivity
The
energy budget of an
ecosystem depends on its
primary productivity.
What is gross primary
productivity? (GPP)
GPP represents energy available
to consumers in an ecosystem.
What
is Net Primary Productivity?
(NPP)
NPP =
GPP - R
Net Primary Productivity
Why
is NPP a more useful
measurement than GPP?
How is it that the open ocean has low net
productivity yet accounts for most of the
Earth’s total productivity?
Limiting Factors
What sort of factors will
limit productivity?
Light intensity
Water
Inorganic nutrients such as
nitrogen and phosphorus.
CO2
Energy Partitioning Within the Food
Chain
What does this number
represent?
Energy Partitioning Within the Food
Chain
The energy
available for the
next trophic level.
Ecological Efficiency
How
much of energy is actually
available to the next trophic
level?
Usually around 10% is
available
Why is it that we don’t see 6th
order consumers?
Which has more energy, a quarter pound
of salad or a quarter pound of beef ?
How can the producers in the English
Channel support the producers in this
ecosystem?
How many individuals are
supported at the top level of
this ecosystem?
Chemical
Cycling
Biogeochemical Cycles – the way
in which elements, chemical
compounds, and other forms of
matter are passed from one
organism to another and
throughout the biosphere.
(conversion to
organic forms)
What does the loss of nitrates from the
deforested ecosystem tell you about the
water, and about how nitrates are normally
maintained in the ecosystem?
What is going on in this picture?
We’ve Changed Our Tune
The Experimental Eutrophication of
a Lake
Erosion of Earth’s Ozone Shield: The
Ozone Hole Over the Antarctic
Erosion of Earth’s ozone shield: Thickness
of the ozone layer