ENERGY FLOW THROUGH
ECOSYSTEMS
Spring 2012
ENERGY FLOW THROUGH ECOSYSTEMS
All organisms MUST
obtain and use
energy…
ENERGY ROLES (JOBS) IN
ECOSYSTEMS
 Each organism in an ecosystem has a role or niche.
 Producer’s Role – make their own food through
photosynthesis, convert the Sun’s energy to make
glucose, provide food for 1 st and 3 rd level
consumers.
 Examples: Any plant… Grasses, shrubs, trees,
algae… etc.
ENERGY ROLES (JOBS) IN
ECOSYSTEMS
 1 st Level Consumer (Herbivores) Role-must
consume another organism to obtain energy,
ONLY CONSUME PLANTS, provide food for
2 nd and 3 rd level consumers.
 Examples: Deer, rabbits, rodents (mice,
rats, squirrels), insects, herbivorous birds,
etc.
ENERGY ROLES (JOBS) IN
ECOSYSTEMS
 2 nd Level Consumer (Carnivores) Role-must
consume another organism to obtain energy,
ONLY CONSUME OTHER CONSUMERS,
provide food for 3 rd level consumers.
 Examples: snakes, foxes, predatory birds,
jellyfish etc.
ENERGY ROLES (JOBS) IN
ECOSYSTEMS
 3 rd Level Consumer (Omnivores and Large
Carnivores) Role-must consume another
organism to obtain energy, CONSUMES
OTHER CONSUMERS and/or PRODUCERS,
provide food for scavengers.
 Examples: Humans, lions, bears,
sharks, whales.
ENERGY ROLES (JOBS) IN
ECOSYSTEMS
 Scavenger’s Role-must consume another
organism to obtain energy, CONSUMES DEAD
ANIMAL REMAINS, provide food for other
scavengers.
 Examples: Hyenas, buzzards, flies, snails.
ENERGY ROLES (JOBS) IN
ECOSYSTEMS
 Decomposer’s Role-must consume another
organism to obtain energy, BREAK DOWN
DEAD PLANT AND ANIMAL REMAINS,
provide food other organisms.
 Examples: fungi, bacteria, earthworms,.
ENERGY ROLES (JOBS) IN
ECOSYSTEMS
Bacteria: are decomposers that
break down animal remains.
Fungus: are decomposers that break
down plant remains.
Role for BOTH: returns materials to
the soil, clean up the environment
ENERGY FLOW
 Food Chains: shows ONE possible path for
the flow of energy for a particular
organism in an ecosystem.
 Rules:
A. Must start with producers to 1 st level
consumer to 2 nd, and so on.
B. Must use arrows to show the direction of
energy flow.
Organism that
is eaten
Organism that is
eating
FOOD CHAIN EXAMPLES
ENERGY FLOW
 Food Web: Many overlapping food chains in an
ecosystem.
 Shows relationships & dependencies to others.
 Rules:
A. Must start with producers to 1 st level
consumer to 2 nd, and so on.
B. Must use arrows to show the direction of
energy flow (arrows may overlap).
FOOD
WEB
EXAMPLE
ENERGY FLOW
 Energy Pyramids: Shows the flow of energy in a
food chain with LESS energy as each level
goes up.
 Rules:
A. Producers go on the bottom, 3 rd level
consumer on top.
B. Must have more producers than 1 st level
consumers, more 1 st than 2 nd , more 2 nd than
3 rd, etc.
ENERGY PYRAMID
TWO T YPES OF ORGANISMS
Autotrophs: Organisms that can make their
own food. (Producers)
Heterotrophs: Organisms that cannot make
their own food, they must consume.
(Consumers, Scavengers, Decomposers)