Energy Flow
Through an
Ecosystem
Food Chains, Food Webs,
Energy Pyramids
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•Begins with the
SUN
•Through a process
called
Photosynthesis
6CO2 + 6H2O + sunlight & chlorophyll
C6H12O6 + 6O2
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Photosynthesis
•Chemical reaction where green plants
use water & carbon dioxide to store the
sun’s energy in glucose
ENERGY is stored in glucose
Glucose is stored as starch in plants
•
•
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Organisms that can
make glucose during
photosynthesis are
called PRODUCERS.
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Producers use
most of the
energy they make
for themselves.
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Producers use
cellular respiration
to supply the
energy they need
to live.
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6O2 + C6H12O6 --> 6H2O + 6CO2 + energy
CELLULAR
RESPIRATION is
the chemical
reaction that
releases the
energy in glucose.
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The energy that is not
used by producers can
be passed on to
organisms that cannot
make their own
energy.
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Organisms that
cannot make their
own energy are called
CONSUMERS.
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Consumers that eat producers
to get energy:
•Are first order (1 ) or
primary consumers
•Are herbivores (plantst
eaters)
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Most of the
energy the
primary consumer
gets from the
producer is used
by the consumer.
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Some of the
energy moves into
the atmosphere as
heat.
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Some energy in the
primary consumer is
STORED & not lost
to the atmosphere or
used by the
consumer itself.
This energy is
available for another
consumer (predator).
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A Consumer that Eats Another
Consumer for Energy:
•Is called a secondary or
2nd order consumer
•May be a carnivore or
a omnivore
•May be a predator
•May be a scavenger
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Most of the
energy the
secondary
consumer gets
from the primary
consumer is used
by the secondary
consumer.
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Some of the
energy is lost as
heat, but some
energy is stored
and can passed
on to another
consumer.
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A consumer that eats a
consumer that already ate a
consumer:
•Is called a 3rd order
or tertiary consumer
•May be a carnivore or
a omnivore
•May be a predator
•May be a scavenger
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Consumers that eat producers
& other consumers
Are called
omnivores
Omnivores
eat plants
and
animals
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Consumers that hunt &
kill other consumers are
called predators.
The animals that are
hunted & killed are
called prey.
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Consumers that eat
other dead consumers
are called scavengers
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The transfer of energy from
the sun to producer to primary
consumer then to higher order
consumers can be shown in a
FOOD CHAIN.
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Food Chains Show Available Energy
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More Food Chains
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Another way
of showing the
transfer of
energy in an
ecosystem is
the
ENERGY
PYRAMID
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Energy Pyramids Show
•Amount of available
energy decreases for
higher consumers
Amount of available
energy decreases down the
food chain
It takes a large number
of producers to support a
small number of primary
consumers
It takes a large number
of primary consumers to
support a small number of
secondary consumers
•
•
•
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Food Webs:
•Are
interconnected
food chains
They show the
feeding
relationships in
an ecosystem
•
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How Many Chains are in
this web?
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Identify the Producers, Consumers, &
Decomposers:
Count the
Food
Chains!
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Click the link and complete the energy pyramid for each ecosystem.
On a separate sheet of paper, complete an energy pyramid for 1 of the
ecosystems.
http://www.mhhe.com/biosci/genbio/virtual_labs/BL_02/BL_02.html
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