FOOD CHAINS& WEBS
Energy Flow in Ecosystems1. What provides the energy for the
biological world?
THE SUN!
Energy Flow
Organisms called autotrophs can use the sun’s energy to make their own food through photosynthesis.
2. How does the sun’s energy enter the biological world?
Energy Flow3. What is
photosynthesis?The process by which autotrophs convert the sun’s energy into organic material.
consumer 1
Energy Flow
• The sun’s energy flows into organisms that can change the sunlight into food then into organisms that eat them.
This flow is:
sunlight producer consumer 2
4. How does energy flow from plant to other organisms?
Word to Know
producer
detritivore
omnivore
carnivoreherbivore
consumer
decomposer
top
carnivore
PRODUCERSWhat are producers?• Autotrophs that trap solar energy into
organic molecules during photosynthesis; can produce their own food
• Ex. Plants, algae and some bacteria
``
sunlight producer consumer 1 consumer 2
CONSUMERSWhat are consumers?• Heterotrophs that eat other
organisms to obtain energy• Examples: deer, rabbits, cows, mice,
lions, humans, hawks, snakes
sunlight producer consumer 1 consumer 2
HERBIVORESWhat are herbivores?• Organisms that eat
plants• Primary Consumers• Ex. Cows, caterpillars, bunnies
sunlight producer consumer 1 consumer 2
CARNIVORESWhat are carnivores?• Organisms that eat meat (other
animals/consumers)• Secondary Consumers• Ex. tigers, wolves, snakes, hawks
sunlight producer consumer 1 consumer 2
TOP CARNIVORESWhat is a top-level carnivore?• Top-level carnivores eat secondary
consumers; usually nothing feeds on them
• Ex. killer whale eating a sea lion or hawk eating a snake.
consumer 3
sunlight producer consumer 1 consumer 2
OMNIVORESWhat are omnivores?• Consumers that eat both plants and
animals• Primary and Secondary Consumers• Ex. bears and humans
Where do allthe dead things go?
• They are eaten. YUMMMM!
• They decay. SMELLY!
decomposerdetritivore
Detritivore vs Decomposers• Detritivores and decomposers both feed
on the remains of dead plants and animals and other dead matter (detritus)
• They rely on dead tissues for nutrients.
decomposerdetritivore
• Detritivores eat the remains of dead plants and animals
• Decomposers breakdown (decay) organic matter and feed on it
Crabs, mites, earthworms, snails
Bacteria & fungi
Detritivore vs Decomposers
What is a scavenger?• A scavengers is a
type of detritivore that feeds on dead animal remains.
Detritivore vs Decomposers
Ex. vultures, sharks, maggots, hyenas
13. Why would they be called the environmental “recyclers”?
• They decompose excrement, dead bodies and leaf litter, returning nutrientsto the physical environment.
decomposer
Detritivore vs Decomposers
consumer 3
sunlight producer consumer 1 consumer 2
Energy Flow14. The series of steps in which
organisms transfer energy by eating and being eaten is called a Food Chain
sunlight producer consumer 1 consumer 2
Food Chains & Food Webs15. The steps in the transfer of energy from
organism to organism in feeding relationships are called Trophic Levels.
16. How does a food chain describe this path of energy? (arrows)
producer consumer 1 consumer 2 consumer 3
Food Chains & Food Webs• Name the number of the trophic levels in
the food chain below.• How do the trophic level numbers
correspond with the “eating terms”?
TrophicLevel 1 2 3 4
producer consumer 1 consumer 2 consumer 3
Food Chains & Food Webs17. Why is it that some energy is lost from
one level to the next level?• Some energy is lost as heat energy or in
metabolism (daily life activities).
producer consumer 1 consumer 2 consumer 3
Food Chains & Food Webs18. How much energy is actually passed on
to the next level? (rule of thumb)• 10%
producer consumer 1 consumer 2 consumer 3
Food Chains & Food Webs• What vital “recycler” is not shown in
this food chain?• Upon which organism(s) would it
feed?
decomposer
producer consumer 1 consumer 2 consumer 3
Food Chains & Food Webs19. If all of the snakes in this chain died, what
would happen to the hawk?
consumer 2
decomposer
producer consumer 1 consumer 3
•They would die or have to find a new food supply
Food Chains & Food Webs
• They would not be severely affected as they have a multiple food source.
consumer 2
decomposer
producer consumer 1 consumer 3
20. To the decomposers?
Food Chains & Food Webs21. Most organisms feed on more than one
trophic level and feed on several different species at each trophic level. This is a food web.
Antarctic Food Web
Making a Food Web• Use these organisms for Food Chains and
Food Web Practice worksheet.