Energy in
Ecosystems
MRS. PIT TALUGA
8 TH GRADE SCIENCE
I can…
Identify food chains within food webs
and label the trophic levels to which
each organism belongs.
◦ NC Essential Standard – 8.L.3.3: Explain how the flow of
energy within food webs is interconnected with the
cycling of matter (including water, nitrogen, carbon
dioxide, and oxygen)
producers
• An organism that makes its
own food through a chemical
reaction – photosynthesis or
chemosynthesis
• Also called autotrophs
consumers
• An organism that consumes
other organisms for food
• Heterotrophs
• Herbivores, Carnivores,
Omnivores
decomposer
Organisms that break
down the remains of dead
organisms and other
organic waste
Food Chain
◦ Diagram that shows how
matter and energy move
through an ecosystem
◦ Grass  Rabbit  Snake 
Hawk
─ Arrows show direction the
energy is moving
─ Food chains always start with a
plant
─ Usually have only 3-5 levels
─ Energy is lost when moving up
the food chain.
Trophic Levels:
◦ The level an organism belongs
to is determined by its distance
from the producer
◦ 1st Trophic Level – Producers
◦ 2nd Trophic Level – Primary
consumers
◦ 3rd Trophic Level – Secondary
consumers
◦ 4th Trophic Level – Tertiary
consumers
Food Web
◦ More complex than a food
chain
◦ Shows all the possible
feeding relationships at
each trophic level in a
community
─ More realistic than a food
chain
─ Most heterotrophs depend on
more than one species for
food or energy.
I can…
Interpret an energy pyramid to
determine what happens (and why it
happens) to the amount of energy as
you move up the trophic levels.
The Energy Pyramid
• The energy pyramid
is a visual
representation of the
flow of energy within
a community.
• It is designed to show
the amount of
biomass at each
trophic level.
• Biomass is the
amount of living or
organic matter within
an organism
10% Rule of
Ecology
An average of
only 10% of
the energy in
one trophic
level is passed
to the next
trophic level.
Energy Pyramid Foldable