Patterns of Feeding
Relationships in an
Ecosystem
Energy Sources
Energy Source
Producer Makes own food
through
photosynthesis
Consumer Get energy by
eating producers
or other
consumers
Examples
Grass,
trees
Mice,
elephants,
humans
Identify the following
examples as either a producer
or consumer
1)
2)
3)
4)
Flowering plants
Turtles
Ants
Ferns
Types of Consumers
Herbivore – eats plants
Omnivore – eats plants and animals
Carnivore – eats only animals
Decomposer – eats breaking down dead
organisms
Decomposition
Organisms die at ALL LEVELS of the
food chain
As organisms die they decompose into
organic material. This organic material
produces nutrients that producers need
to grow.
Types of Consumers in an Ecosystem
Who they eat Examples
Herbivore
Producers
Carnivore
Consumers
Omnivore
Producers &
Consumers
Decomposer Dead
organisms
Cows,
sheep
Lions,
whales
Bears,
pigs,
humans
Fungi
bacteria
Identify the following examples
as a herbivore, carnivore,
omnivore or decomposer
1)
2)
3)
4)
Bacteria
Sharks
Deer
Raccoons
Autotrophs vs. Heterotrophs
Autotrophs – make their own food
Heterotrophs – feed on other organisms
for their food
Food Chain
1) Primary Producers
Characteristics
• Autotrophs
• Largest trophic level in a
food chain
2) Primary Consumers
Characteristics
• Heterotrophs
• Herbivores (Eat primary
producers)
Food Chain
3) Secondary Consumers
Characteristics
• Heterotrophs
• Carnivores (Eat primary
consumers)
4) Tertiary Consumers
Characteristics
• Heterotrophs
• Omnivores (can eat from all
trophic levels)
I am eating a cheese pizza. What trophic
levels am I eating?
I am eating a steak and salad. What
trophic level am I eating?
Energy Pyramid
Tertiary Consumers
10 kcal
Secondary Consumers
100 kcal
Primary Consumers
1,000 kcal
Producer
10,000 kcal
Sunlight
1,000,000,000 kcal
90% of energy is lost from one trophic level to
the next. This excludes sunlight.
Where the lost energy in an
Energy Pyramid Goes
Used up by the organism in the form of:
1) Heat
2) Producing new cells
3) Regulating body temperature
4) Moving
How Energy Loss Affects an
Ecosystem
1) Fewer animals at higher trophic levels
2) Limits the number of trophic levels in
an ecosystem
Biomass
Mass of all the biological organisms in
one trophic level.
What trophic level would have the
greatest Biomass?
Why is a pound of bacon so much more
expensive than a pound of corn?
Food Web
Network of interconnecting food chains
Represents ALL the possible feeding
relationships in an ecosystem
Food Web Activity
In your group construct a Food Web using
yourselves and string. Be sure to
include decomposers, producers,
primary consumers and tertiary
consumers.