Food Chains and Food Webs

Interactions in our Environment
Learning Goals:
 Describe a food chain and the effect of losing a
part of that chain.
Success Criteria:
 I can describe a food chain/web and discuss what
happens when one part of the food web is lost.
All energy in ecosystems originate with the
sun. As we learned last lesson, plants absorb
energy and turn it into foods such as sugars
and starches.
Animals eat the plants and the energy is
Carnivores and omnivores eat those animals
and energy is again transferred.
Food Chain (def): A sequence that shows how
energy and nutrients are transferred from one
organism to another in an ecosystem.
The number of “links” in a food chain can
vary, but it always starts with a producer and
ends with a consumer.
2 links
5 links:
In real ecosystems, food chains are not that
Producers (plants) are usually eaten by many
different consumers (animals) which in turn
can be eaten by many other animals.
Food Web (def): A model that shows how
food chains in an ecosystem are connected.
In your group, create a food web.
Work together to think of as many plants and
animals as possible that will be part of your web.
Animals/plants must be realistic and links
must be accurate (e.g. A bear does not eat a
 You must identify your ecosystem!
 Your group will have 8 minutes to make your
web. Be ready to present.
 Which group will have the most connections?
What happens when
one species is
eliminated from the
(Discuss as a class)
If one species is eliminated (e.g. goes extinct)
it affects the other species in that food web.
Sometime other species will die or they may
find an alternate source of food.
When any part of a food web is changed the
flow of energy is affected in a food web. We
will be studying energy flows next.
Food Chains, Food Webs and Energy
Pyramids in Ecosystems
Food chains/webs show how energy moves
from one organism to another but they do
not show how the energy is used.
Work with a partner to find the important
information and make jot notes about the
information on pages 132-134. (Hint: divide
the information into headings, following the
text and use diagrams to help you illustrate
and understand)