Trophic Levels,
Energy transfer
and Pyramids
Trophic
Levels – is the
position an organism
occupies in a food
chain. It refers to food or
feeding.
Food Chain
Food Chains
The
energy flow from one trophic level
to the other is know as a food chain
Producers are at the first ENERGY LEVEL
Primary Consumers are the SECOND
ENERGY LEVEL
Secondary consumers are at the THIRD
ENERGY LEVEL
Trophic Levels (feeding levels)
3
2
1
Food Web
Food
webs are
multiple food chains.
Food Webs
Food webs show
ALTERNATIVE PATHWAYS
other possible pathways
through which an
organism can obtain
energy
Food webs
Energy Level
Grass
Mouse
Grasshopper
Frog
Owl
Hawk
1st
2nd
Producer, primary
consumer, secondary
consumer, tertiary
consumer?
producer
Primary
consumer
Energy Level
Producer, primary
consumer, secondary
consumer, tertiary
consumer
Producer
Grass
1st
Mouse
2nd
Primary consumer
Grasshopper
2nd
Primary consumer
Frog
3rd
Secondary
consumer
Owl
3rd and 4th
Hawk
3rd
Secondary and
tertiary consumer
Secondary
consumer
Transfer of Energy
Energy
lost from chain
“link” to “link” is
significant!
from grass to sheep, loss is about
90%!
HEAT
90%
HEAT
90%
100% Energy
Available
10% Original
Energy!
1% Original
Energy!
Energy lost from one trophic level
(energy level) to the next level can be
represented by a pyramid
4⁰
CONSUMERS
3
CONSUMERS
2 CONSUMERS
1 CONSUMERS
PRODUCERS
Each level above only gets
10% of the energy from below

Ex: 10,000 J of producers (plants) only give 10% of
energy to primary consumers
1,000 J to primary consumers (snails,
minnows, dragonflies)
100 J to secondary consumers (small fish)
10 J to tertiary consumers (big fish)
1 J to quaternary consumers (fish hawk)
ENERGY PYRAMID
1J
10 J
100 J
1,000 J
10,000 J
Usually
no more than 5 trophic
levels since 6th level would have
very little energy to keep it alive
Ecological Pyramid
•
•
•
•
Which
Which
Which
Which
level
level
level
level
has
has
has
has
the
the
the
the
most energy?
most organisms?
least organisms?
least energy?