1. Food Chains and Food Webs
Interactions in our Environment
Food Chains and Food Webs

2. Food Chains and Food Webs
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.

3. Where do we get our Energy?
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 transferred.
Carnivores and omnivores eat those animals and energy is again transferred.

4. A food chain is created....
sun
grains
chicken
Chicken dinner
Food Chain (def): A sequence that shows how energy and nutrients are transferred from one organism to another in an ecosystem.

5. Food Chains
The number of “links” in a food chain can vary, but it always starts with a producer and ends with a consumer.
dandelion
aphid
ladybug
robin
hawk
Blueberry bush
bear
2 links
5 links:

6. Food Webs In real ecosystems, food chains are not that simple.
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.

7. A more realistic Food Web
Discuss interactions with class.

8. Your Turn.... 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 lion!)
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?
Give each group a piece of chart paper and marker. Time.

9. Changes in Food Chains/Webs
What happens when one species is eliminated from the web? (Discuss as a class and run Gizmos simulation)
Discuss with class

10. Changes in Food Chains/Webs
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.

11. Let’s Review Food Webs and Introduce Energy Flows
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.

12. Energy Flow in an Ecosystem
1. Work with a partner to find the important information and make jot notes about the information on pages (Hint: divide the information into headings, following the text and use diagrams to help you illustrate and understand)
2. Go to Gizmos in the Hub and complete the quiz for Food Chains
Try to work with IEP students in small group at guided reading table to ensure understanding. Check to see that students completed summaries. May need to photocopy good notes for IEP students. Take up next day.