1. Flow of Energy Through Living Systems
Food Chains
Food Webs
Energy Pyramids

2. • Begins with the SUNBegins with the SUN
• PhotosynthesisPhotosynthesis
6CO2 + 6H2O + sunlight & chlorophyll C6H12O6 + 6O2

3. Photosynthesis
• Is a chemical reaction where green plantsIs a chemical reaction where green plants
useuse waterwater andand carbon dioxidecarbon dioxide to store theto store the
sun’sun’s energys energy in the form ofin the form of glucose.glucose.
• ENERGY is stored in glucoseENERGY is stored in glucose
• Glucose isGlucose is
stored asstored as
starchstarch inin
plantsplants

4. Organisms that can make glucose
during photosynthesis are called
PRODUCERS.

5. 5
ProducersProducers
use most of theuse most of the
energy they makeenergy they make
for themselves.for themselves.
copyright cmassengale

6. Producers
use cellular respiration
to supply the energy they need to live.

7. CELLULAR RESPIRATION
is the chemical reaction
that releases the energy in glucose.
6O2 + C6H12O6 --> 6H2O + 6CO2 + energy

8. The energy that is not used by
producers can be passed on to
organisms that cannot make
their own energy.

9. Organisms that cannot make their
own energy are called
CONSUMERS.

10. Consumers that eat Producers
to get energy:
• Are first order or primary consumers
• Are herbivores (plant-eaters)

11. Most
of the energy
the primary consumer gets from the
producer is used by the consumer.

12. Some
of the energy
moves
into the atmosphere
as heat.

13. Some
of the energy
is not lost to the atmosphere
or used by the consumer.
This energy is available for
another consumer.
(about 10%)

14. A consumer that eats another
consumer for energy:
• Is called a secondary or
second order consumer
• May be a carnivore
or an omnivore
• May be a predator
• May be a scavenger

15. Most
of the energy the
secondary consumer gets
from the primary consumer is
used by the secondary
consumer.
Secondary
consumer

16. Some
of the energy
is lost as heat,
but some energy
is stored and can be passed on
to another consumer
(about 10%).

17. A consumer that eats a consumer
that already ate a consumer:
• Is called a third order or tertiary consumer
• May be a carnivore or an omnivore
• May be a predator
• May be a scavenger

18. Consumers that eat xx
producers & other consumers
• Are called omnivores
• Omnivores eat plants
and animals

19. Consumers
that hunt & kill other consumers
are called predators.
The animals that are
hunted & killed are called prey.

20. Consumers
that eat other consumers
that have already died are called
scavengers.

21. Consumers
that chemically breakdown
organic matter like animal
remains are called
decomposers.

22. The transfer of energy
from sun
to producer
to primary consumer
to secondary consumer
to tertiary consumer
can be shown in a FOOD CHAIN.

23. FOOD CHAINS
A food chain shows the path of
energy from one organism to the
next
– energy flows from producers to
consumers
– arrows point to who is eating
(plant is eaten by herbivore)
– Can vary in lengthCan vary in length
– Usually decomposers are left out

24. Another food chain

25. Another way of showing the
transfer of energy in an
ecosystem is the
ENERGY PYRAMID.

26. 10% Rule
ONLY 10% of the energy from an
organism on one level can be passed
on to an organism on the next level.

27. Energy Pyramids
show • That the amount of available
energy decreases up the
food chain
• It takes a large number of
producers to support a small
number of primary
consumers
• It takes a large number of
primary consumers to
support a small number of
secondary consumers
E
N
E
R
G
Y
L
O
S
S

28. Producers
1st
Order Consumers
(Herbivores)
2nd
Order Consumers
(Carnivore or Omnivore)
3rd
Order Consumers
(Carnivore or Omnivore)
E
N
E
R
G
Y
L
O
S
S

29. Food WebsFood Webs
• FeedingFeeding relationshipsrelationships are much moreare much more
complicated than a single, one-waycomplicated than a single, one-way
chainchain
• Many animals eat more than one kindMany animals eat more than one kind
of foodof food
• Food webs show these relationshipsFood webs show these relationships

30. Food Webs:
• Are interconnected
food chains
• They show the
feeding relationships
in an ecosystem

31. FOOD WEBS
• Typically, food webs go like this:
PRODUCER
CONSUMER
(HERBIVORE)
CONSUMER
(CARNIVORE)
CONSUMER
(OMNIVORE)
DECOMPOSER
remember:
decomposers
receive energy
from all other
organisms in
an ecosystem

32. FOOD CHAINS AND WEBS
• Practice! Draw a food
chain that includes the
following organisms:
– grasshopper
– mouse
– grass
– owl
• Now label the organisms
as producers, consumers
(which type?), or
decomposers PRODUCER
CONSUMER
(HERBIVORE)
CONSUMER
(CARNIVORE)
CONSUMER
(CARNIVORE)

33. FOOD CHAINS, WEBS & ENERGY PYRAMIDS
• Food chains/webs can
be written as a pyramid:
– Producers form the
base of the pyramid
– Consumers
form the upper
layers

34. ReviewReview
Identify the following as producers orIdentify the following as producers or
consumers.consumers.
• FungiFungi
• CowsCows
• HumansHumans
• MushroomsMushrooms
• GrassGrass
• TreesTrees
• MouseMouse

35. ReviewReview
Young rabbits that eat grass are sometimes eaten
by raccoons, which also eat seeds and berries.
Bacteria help to decompose the excretions of the
raccoon. Which statement about these nutritional
relationships is accurate?
1.1. Bacteria are scavengers.Bacteria are scavengers.
2.2. Rabbits are secondary consumers.Rabbits are secondary consumers.
3.3. Raccoons eat only producers.Raccoons eat only producers.
4.4. Raccoons are both primary and secondary consumers.Raccoons are both primary and secondary consumers.

36. ReviewReview
Base your answer on the chart and yourBase your answer on the chart and your
knowledge of biology. Which is an example ofknowledge of biology. Which is an example of
the nutritional pattern of a primary consumer?the nutritional pattern of a primary consumer?
1.1.prickly pear cactuses – desert ratsprickly pear cactuses – desert rats
2.2.grasshoppers – lizardsgrasshoppers – lizards
3.3.scorpions – bacteriascorpions – bacteria
4.4.lizards – roadrunnerlizards – roadrunner

37. ReviewReview
Which statement best describes anWhich statement best describes an
energy pyramid?energy pyramid?
1.1.There is more energy at the consumer level thanThere is more energy at the consumer level than
at the producer level.at the producer level.
2.2.There is more energy at the producer level that atThere is more energy at the producer level that at
the consumer level.the consumer level.
3.3.There is more energy at the secondary-consumerThere is more energy at the secondary-consumer
level than at the primary-consumer level.level than at the primary-consumer level.
4.4.There is more energy at the decomposer levelThere is more energy at the decomposer level
than at the consumer level.than at the consumer level.

38. ReviewReview
The diagrams represent four members of a foodThe diagrams represent four members of a food
chain. Which sequence best represents thechain. Which sequence best represents the
transfer of energy between these organisms?transfer of energy between these organisms?
1.1.toads – predaceous insects – herbivoroustoads – predaceous insects – herbivorous
insects – plantsinsects – plants
2.2.predaceous insects – herbivorous insects –predaceous insects – herbivorous insects –
plants – toadsplants – toads
3.3.plants – herbivorous insects – predaceousplants – herbivorous insects – predaceous
insects – toadsinsects – toads
4.4.plants – herbivorous insects – toads –plants – herbivorous insects – toads –
predaceous insectspredaceous insects

39. ReviewReview
If birds eat insects that feed on corn, whichIf birds eat insects that feed on corn, which
pyramid level in the diagram would birdspyramid level in the diagram would birds
occupy?occupy?
1.1. AA
2.2. BB
3.3. CC
4.4. DD

40. ReviewReview
Compared to the energy contained in theCompared to the energy contained in the
plants eaten by cows, the amount of energyplants eaten by cows, the amount of energy
available to the organisms that eat the cows isavailable to the organisms that eat the cows is
less, since cowsless, since cows
1.1. reproduce rapidly and pass on most of the energy toreproduce rapidly and pass on most of the energy to
their offspringtheir offspring
2.2. convert solar energy to foodconvert solar energy to food
3.3. store all their energy in milkstore all their energy in milk
4.4. use energy for their own metabolismuse energy for their own metabolism

41. ReviewReview
In an ecosystem, the more livingIn an ecosystem, the more living
requirements that two different speciesrequirements that two different species
have in common, the more intense will behave in common, the more intense will be
their…their…
1.1.ecological successionecological succession
2.2.competitioncompetition
3.3.energy requirementsenergy requirements
4.4.adaptationadaptation