Food Chains, Food Webs, Energy
Pyramids

A visual representation of how energy is
transferred in a system
Grass
Producer
Produce their own
energy (autotrophs)
Grasshopper
Snake
Consumers
Depend on other organisms for their
energy (heterotrophs)
Hawk
Grass
Grasshopper
Snake
We call each level of the food chain a “trophic” level
– meaning energy level. Each trophic level shows
how energy is being transferred from one animal to
another. Each level is designated with specific
terminology.
Hawk
Grass
Grasshopper
Snake
Primary producer
Make their own food from the energy they gain from
the sun.
Hawk
Primary Consumer
Get their energy directly from producers. This level
of the food chain is occupied by either herbivores or
omnivores – those organisms that eat plant tissue as
part or all of their diet.
Secondary Consumer
Get their energy directly from other organisms. This
level of the food chain is occupied by either
carnivores or omnivores – those organisms that eat
animal tissue as part or all of their diet.
Tertiary Consumer
Get their energy directly from other organisms. This
level of the food chain is occupied by either
carnivores or omnivores – those organisms that eat
animal tissue as part or all of their diet.
Beyond tertiary consumers
There is a possibility of another level (quaternary
consumers). This is a very rare occurrence. The last
trophic level is often referred to as the top-level
consumer – this is the consumer that doesn’t have
many organisms that want to eat it (like humans).
Is the top-level consumer safe?
Just because there isn’t an organism that eats them,
there is an aspect of a food chain that takes the
energy of the top level consumer and places it back
into the food chain system.
Decomposer
These organisms feed from the dead tissue.
They break it down into simple nutrients
that are returned to the soil that is used by
the plants.
Fungi
A.
B.
C.
D.
A
B
C
D
Primary Producer
Secondary Consumer
Tertiary Consumer
Quaternary Consumer
A.
B.
C.
D.
A
B
C
D



The food chain implies that our consumers
only eat ONE thing, but that is not the case
Just like you, animals of all types like a variety
of food…
Therefore we rely on a food web to show us the
entire energy transfer that is happening within
an ecosystem.
A.
B.
Yes
No



In truth, only 10% of the overall energy is
transferred from one trophic level to another.
How does this affect the number of trophic
levels an ecosystem can support?
When you start with a limited supply, each
level only gets 10% of that previous level

100%  10%  1% 0.1%
Primary Producer
0.1%
1%
10%
100%
Tertiary Consumer
Secondary Consumer
Primary Consumer
• The pyramid shows a picture of less
energy at each level
Less Energy,
small
population
• The pyramid also represents the
amount of organisms that can be present
at each level
0.1%
1%
10%
More Energy,
large
population
100%



Only 10% of the previous level’s energy passes on,
so where does the rest go?
Law of Conservation of Energy states: Matter
(Energy) is neither created nor destroyed.
Therefore, what is not passed on must be used by
the organism

The energy is used for basic function





Breathing
Running
Reproduction
Digesting
Released as heat
A.
B.
A food web
A food chain
A.
B.
C.
D.
E.
F.
Being made up of many overlapping food
chains
An organism that converts heat or light energy
from the sun into other energy
A model that shows how energy is lost as it is
transferred up the food chain
An organism that gets its energy by eating
plants or animals
A model that shows one set of feeding
relationships between a producer and several
consumers
An organism that breaks down dead plants and
animals into simpler compounds
A.
B.
C.
D.
E.
F.
Being made up of many overlapping food
chains
An organism that converts heat or light energy
from the sun into other energy
A model that shows how energy is lost as it is
transferred up the food chain
An organism that gets its energy by eating
plants or animals
A model that shows one set of feeding
relationships between a producer and several
consumers
An organism that breaks down dead plants and
animals into simpler compounds
A.
B.
C.
D.
E.
F.
Being made up of many overlapping food
chains
An organism that converts heat or light energy
from the sun into other energy
A model that shows how energy is lost as it is
transferred up the food chain
An organism that gets its energy by eating
plants or animals
A model that shows one set of feeding
relationships between a producer and several
consumers
An organism that breaks down dead plants and
animals into simpler compounds
A.
B.
C.
D.
E.
F.
Being made up of many overlapping food
chains
An organism that converts heat or light energy
from the sun into other energy
A model that shows how energy is lost as it is
transferred up the food chain
An organism that gets its energy by eating
plants or animals
A model that shows one set of feeding
relationships between a producer and several
consumers
An organism that breaks down dead plants and
animals into simpler compounds
A.
B.
C.
D.
E.
F.
Being made up of many overlapping food
chains
An organism that converts heat or light energy
from the sun into other energy
A model that shows how energy is lost as it is
transferred up the food chain
An organism that gets its energy by eating
plants or animals
A model that shows one set of feeding
relationships between a producer and several
consumers
An organism that breaks down dead plants and
animals into simpler compounds
A.
B.
C.
D.
E.
F.
Being made up of many overlapping food
chains
An organism that converts heat or light energy
from the sun into other energy
A model that shows how energy is lost as it is
transferred up the food chain
An organism that gets its energy by eating
plants or animals
A model that shows one set of feeding
relationships between a producer and several
consumers
An organism that breaks down dead plants and
animals into simpler compounds
A.
B.
C.
D.
fungi
animals
water
sunlight