1. Energy Flow in Ecosystems Food Chains and Food Webs
Chapter 3.3
Energy Flow in Ecosystems
Food Chains and Food Webs

2. Food Chain
A sequence that

3. Food Chain
Phytoplankton:
A primary producer
A mixture of

4. Trophic Levels Primary Consumers Tertiary Consumers
Are herbivores.
First consumer above producer trophic level.
Secondary Consumers
Tertiary Consumers
Carnivores that eat secondary consumers

5. Trophic Level
When a person eats a salad, the trophic levels in the food chain are
producer-omnivore.
When a person eats a steak, the trophic levels are:

6. Trophic Level
The more levels that exist between a producer and a consumer…
the smaller the percentage of the original energy from producers is available to the consumer.
On pg. 77 figure 3-11, what % of the original energy would be available for organisms?

7. Food Web
Made of several interconnected food chains.

8. Food Chains within Food Webs
In compositions, list out 3 of the individual food chains that are present in this food web.

9. Decomposers and Detritivores
Decomposers convert dead material to detritus, which is eaten by detritivores
like crayfish, grass shrimp, and worms.
Decomposition process releases nutrients that can be used by primary producers.
Without decomposers, nutrients would remain in

10. Food Web in the Everglades
Look on page 75 figure 3-9
What primary producers are shown in this food web?
What can you infer (inference) about vultures from this food web?

11. Food Web in the Everglades
Look on page 75 figure 3-9
What do the orange arrows in the diagram show?
How does the food chain compare to the food web?

12. Trophic Levels and Ecological Pyramids
Pyramid of Energy:
Amount of energy at each level
D_____________

13. Trophic Levels and Ecological Pyramids
Pyramid of Biomass:
Grams of organic matter

14. Trophic Levels and Ecological Pyramids
Pyramid of Numbers:
Shows the # of _____________ at each level.

15. Closing
1st-6th period: “Food Web” worksheet 5th period: “Packet”