Transcript Chapter 3.2

Chapter 3.2
Energy Flow
Producers
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Autotroph-organism that can capture
energy from sunlight or chemicals and use
it to produce its own food from inorganic
compounds; also called a producer. All
plants and some microorganisms make
their own food from sunlight.
Producer- organism that can capture
energy from sunlight or chemicals and use
it to produce food from inorganic
compounds; also called an autotroph.
Producers: ENERGY FROM THE
SUN
Photosynthesis- process by which
plants and some other organisms use
light energy to power chemical
reactions that convert water and
carbon dioxide into oxygen and highenergy carbohydrates such as sugars
and starches.
Producers: Photosynthesis
Producers: ENERGY WITHOUT
LIGHT
Chemosynthesis-process by which some
organisms use chemical energy to
produce carbohydrates
Different
feeding
levels
Producers
(autotroph)
Consumers
(heterotroph)
Detrivotore
Herbivore
Carnivore
Omnivore
Decomposers
CONSUMERS
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Heterotroph- organism that obtains
energy from the foods it consumes; also
called a consumer
Consumer- organism that relies on other
organism for its energy and food supply;
also called a heterotroph
Detrivotore- organism that feeds on
plant and animal remains and other dead
matter. Ex: mites, earthworms, snails,
and crabs
Decomposer-organism that breaks down
and obtains energy from dead organic
matter. Ex. bacteria and fungi
Consumers: 3 Kinds of common
heterotrophs
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Herbivore- organism that obtains
energy by eating only plants. Ex:
cows, caterpillars, deers.
Carnivore- organism that obtains
energy from eating animals. Ex:
snakes, dogs and owls.
Omnivore-organism that obtains
energy by eating both plants and
animals. Ex: humans, bears and
crows.
FEEDING RELATIONSHIP: energy flows
through an ecosystem in one direction,
from the sun or inorganic compounds to
autotrophs (producers) and then to
various heterotrophs (consumers).
-3rd level consumer- omnivore
-2nd level consumer- carnivore
-1st level consumer- herbivore
-producer- plants
Food web
examples
FOOD CHAINS:
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Food chain -series of steps in an ecosystem
in which organisms transfer energy by eating
and being eaten
Food web-network of complex interactions
formed by the feeding relationship among
the various organisms in an
ecosystem.
Trophic level-step in a food chain or food
web. Producers make up the first trophic
level. Consumers make up the second, third
and fourth level.
ECOLOGICAL PYRAMIDS
There are 3 ecological pyramids:
1. ENERGY PYRAMID
 Ecological pyramid- diagram that shows
the relative amounts of energy or matter
within each trophic level in a food chain or
food web
Only 10% of energy
available in one
trophic level is
transferred to
organisms at the
next trophic level.
ECOLOGICAL PYRAMIDS
2. BIOMASS PYRAMID
Biomass- total amount of living tissue
within a given trophic level
3. PYRAMID OF NUMBERS
 Pyramid of numbers: is based on the
numbers of individual organisms at
each trophic level.
Vocabulary
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phot – or photo – light
chem.- or chemo – chemistry
synthesis – production of
substance
herb- plant
carn-meat
omni – all
detritus – organic particles
vore - eat
QUESTIIONS:
What are the two main forms of energy
that power living things?
1. Solar energy (the sun) is obtained
by autotrophs in the process of
photosynthesis (plants/algae)
2. Chemical energy is obtained by
autotrophs in the process of
chemosynthesis
(bacteria/microorganisms)
Briefly describe the flow energy among
organisms in an ecosystem.
There is one-way energy flow in the
system. First energy starts from
autotrophs (producers) and moves
up to heterotrophs (consumers), first
herbivores, carnivores, and then
omnivores.
What proportion of energy is transferred
from one trophic level to the next in an
ecosystem?
In general, about 10%
Show the following as food chain:
omnivore, autotroph and herbivore.
Autotroph-> herbivore-> omnivore
Critical thinking: Calculating: Draw an
energy pyramid for a five-step food
chain. If 100% of the energy is available
at the first trophic level, what % of the
total energy is available at the highest
trophic level?
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At the first level (producers) 100%
energy
Second level 10% energy
Third level 1%
Fourth level 0.1%
Fifth level 0.01%