Description:
Discuss the change in available energy from
one trophic level to the next and what the
energy change implies on the organisms found
in the levels. Relate trophic pyramids and food
chains/web.
Goals:
Describe the Concept of the Trophic Levels
Distinguish between food chains and webs.
Define ecological pyramid and explain its
relationship to energy in the ecosystem
Objectives: Day 3
•Describe each level of the Trophic Pyramid in
terms of available energy.
•Interpret and describe food chains and food
webs.
•Describe the relationship between food
chains/webs and the trophic pyramid.
Warm-Up
PART 1
Omnivores
Q = Fill in the Chart
Top
Consumer
A=
Decomposers
Secondary Consumer
(Carnivores)
Primary Consumers
(Herbivores)
Primary Producers
(Autotrophs)
Scavengers
Quiz
 Name all 6 kingdoms of life and provide
one fact about each.
Objectives: Day 3
•Describe each level of the Trophic Pyramid in
terms of available energy.
•Interpret and describe food chains and food
webs.
•Describe the relationship between food
chains/webs and the trophic pyramid.
Warm-Up
PART 2
Design an Energy Pyramid
 Now add examples to each role
 Ex. Instead of Primary Producer use a plant
Red Fox
Deer Mouse
Blackberry
bush
Think…
 Consider the trophic pyramid:
 Which levels generally have predators and/or prey?
 Is there a relationship to physical size of the
organism and location on the pyramid?
 Which organism need the greatest amount of food
to survive?
 What is the purpose of food?
Pair…
 Consider the trophic pyramid:
 Which levels generally have predators and/or prey?
 Is there a relationship to physical size of the
organism and location on the pyramid?
 Which organism need the greatest amount of food
to survive?
 What is the purpose of food?
Share…
 Consider the trophic pyramid:
 Which levels generally have predators and/or prey?
 Is there a relationship to physical size of the
organism and location on the pyramid?
 Which organism need the greatest amount of food
to survive?
 What is the purpose of food?
Trophic Levels and Energy
Predict in your “Pair”
 In what way is energy
transferred from one organism
to another?
 Where would you expect there
to be the greatest amount of
energy available?
 Where would be the least?
 What does that mean for the
organisms on the different trophic
levels?
Trophic Levels and Energy
Share your thoughts with
the class!
 In what way is energy transferred
from one organism to another?
 Where would you expect there to
be the greatest amount of energy
available?
 Where would be the least?
 What does that mean for the
organisms on the different trophic
levels?
Energy
Loss
at each
Step
0.01%
.01%
1%
10%
 Each Trophic Level
has energy
 90% of the energy is
lost when moving
from one level to the
next.
100%
The loss of energy affects the
organisms in the Ecosystem
If there’s less
energy to survive,
then there are less
organisms!
So what happens to
the number of
organisms as you
move from Primary
Produces to Primary
Consumers to
Secondary
Consumers?
Food Chains
 Food Chains = Sequence of energy
being transferred from one organism to
another.
 Trophic Levels = each step of energy
transfer
ISN’T
THIS
A FOOD
CHAIN!
Red Fox
Deer Mouse
Blackberry
bush
Many Food Chains in each
Ecosystem
If you take all of the food
chains in an ecosystem you
get a Food Web
So what does a Food Web
show?
?
 Food webs show all of the possible
transfers of energy in an ecosystem.
So which is more
complex?
 Food Webs or Food Chains?
 Why?
Use the packet of pictures
too…
 Categorize the organisms into:




Primary Source for Earth
Producers
Herbivores
Carnivores
 Now make three food chains
 Include a primary producer, primary
consumer, secondary consumer, top
consumer