Energy Flow
Relationships
* If an ecosystem is to be selfsustaining it must contain
supply of energy which is
available to all the organisms
within the ecosystem.
 The energy must flow
from organism to
organism.
SUN (radiant energy)
Energy
Energy
Energy
Energy Flow
 All organisms need energy
for their life activities.
 The pathways of energy
through the living components
of an ecosystem are
represented by food chains
and food webs.
Food Chain
Green plants convert radiant
energy from the Sun into chemical
energy (food).
Food chain: a series of
organisms through which
food energy is passed in an
ecosystem.
SUN (radiant energy)
Energy
Energy
Energy
 Each consumer level
utilizes approx. 10% of
its energy to build new
tissue - the food for the
next feeding level.
 The remaining
energy is lost in the
form of heat and
unavailable chemical
energy.
SUN
10%
10%
90%
10%
Energy 90%
90% lost as heat, unavailable
Loss of energy

Loss of energy between levels of food chain

To where is the energy lost? The cost of living!
17%
growth
only this energy
moves on to the
next level in
the food chain
energy lost to
daily living
33%
cellular
respiration
50%
waste (feces)
* There’s more energy
st
at the 1 consumer level
nd
than at the 2
consumer level.
Pyramid of Energy
There must be much
more energy at the
producer level in a food
web than at the
consumer levels.
 A pyramid of energy
can be used to
illustrate the loss of
usable energy at each
feeding level.
Pyramid
of Energy
The Energy Pyramid
 Eventually, the energy in an
ecosystem is lost and is
radiated from the Earth’s
system.
* Thus, an ecosystem cannot
sustain itself without the
constant input of energy from
the Sun.
4) Biomass Pyramid
 The decrease of
energy at each feeding
level means less biomass
(amount of organic
matter) at each level.
Pyramid
of biomass
 Thus, the total mass
of carnivores in a
particular ecosystem is
less than the total mass
of the producers.
Pyramid
of biomass
Hawk
Snake
Rabbit
Grass
* The biomass
relationship is a good
example of the balance
in nature, the
homeostasis of an
ecosystem.
2. Which level of consumers has the
greatest energy?
3. Which organisms are the producers?
4. Which organisms have the
greatest biomass?
5. Which organism is the
secondary consumer?
6. Which organism is the tertiary
consumer?
7. Which organism(s) are
predators?
8. Which organism(s) are
herbivores?
9. Which organism(s) are
autotrophs?
10. What is the food chain
represented by this pyramid?
1.
2. What are two food chains represented in this food web?
3. Which organism(s) are the secondary consumers?
4. Which organism(s) are the producers?
5. What would happen to the toad population if there was a decrease in the snake
population?
6. What would happen to the raccoon population if there was a decrease in the
deer population?
7. What would happen to the grasshopper population if there was a increase in the
snake population?