Energy Flow in a Food
Chain/Webs
Energy
• Every living thing needs energy in order to
live
• Every time consumers do something (run,
jump) they use energy
• Plants get their energy from photosynthesis
• Energy is needed for living beings to grow
The Food Chain
• A food chain shows how living thing gets
energy
• Energy is passed from creature to
creature
• Food chains begin with plant-life, and
end with animal-life.
• Arrows are used to represent energy
being passed
Different types of Food Chains
• There can be many links in food chains but
not TOO many
• If there are too many links, then the animal
at the end would not get enough energy
Food Chain with Decomposers
• Food chains make a full circle!
• Energy is passed from plant to animal
to animal to decomposer and back to
plant!
Food Web
• Is a bunch of food
chains in one
• Several
connections may
occur between
organisms
• Ex: Snake gets
energy from frogs
and rabbits
Lets see how well you understand
what we learned so far:
GAME
http://www.sheppardsoftwa
re.com/content/animals/ki
dscorner/games/foodchain
game.htm
Food Chain Reaction
A change in the size of one population
in a food chain will affect other
populations.
This interdependence of the populations
within a food chain helps to maintain the
balance of plant and animal populations
within a community.
Food Chain Reaction
http://www.ecokids.ca/pub/eco_info/topics/frogs
/chain_reaction/play_chainreaction.cfm
http://www.ecokids.ca/pub/eco_info/topics/frogs
/chain_reaction/play_chainreaction.cfm
http://puzzling.caret.cam.ac.uk/game.php?game=f
oodchain
Consumers that eat producers
to get energy:
• Are primary
consumers = FirstOrder
A consumer that eats another
consumer for energy:
• Is called a secondary
consumer= SecondOrder
A consumer that eats a consumer
that already ate a consumer:
• Is called a tertiary
consumer= Third-
order
A consumer that eats a consumer
that ate a consumer that already ate
a consumer:
• Is called a quaternary
consumer = Fourth-
Order
Transfer of Energy in a Food Chain
The transfer of energy (arrows)
1.
2.
3.
4.
5.
Sun to producer
To primary consumer
To secondary consumer
To tertiary consumer
To quaternary consumer
Left Side of your notebook!
• Make a food web using the following
animals. (write don’t draw)
• Include the Arrows showing energy.
Your Turn!
• Use the food web to help you answer all
the questions about the relationships in
the food web.
• If you don’t finish it’s HOMEWORK!!!
Mountain Lion
Second-order
heterotrophs
Hawks
Snakes
Deer
First-order
heterotrophs
Mice
Rabbits
Seed Eating Birds
Autotrophs
Grass
Shrubs
Trees
Name__________________________
Date___________
Period__________
#_____________
Decomposers
ENERGY PYRAMID
Another way of showing the
transfer of energy in an
ecosystem
How is energy being used?
• Some of the energy is being used in the
consumer
• Some energy is lost as heat
• Some energy is stored and can pass on to
another consumer
How much energy is lost?
• At each level only 10% of the energy
available is passed on.
Trophic Levels:
• The trophic level
is the position an
organism holds in a
food chain or web
1. Primary producer
2. Primary Consumer
3. Secondary
consumer
4. Tertiary Consumer
5. Quaternary
Consumer