1. Energy Flow in Food Chains, Food Webs, & Energy Pyramids
Illustrate energy flow in food chains, food webs, and energy pyramids.

3. Food Chains
Food chains use pictures or words and arrows to show the movement of energy through the trophic levels of organisms.
The trophic level of an organism indicates the position that the organism occupies in the food chain.
It shows what it eats and what eats it.

4. Producers & Consumers
The levels are numbered according to how far the particular organism is along the chain.
Producers are at level 1. (Plants are producers because they produce their own food.)
Herbivores are at level 2. (consumer)
Predators are at level 3. (consumer)
And so on…

5. Anything that cannot make its own food must eat to survive
Anything that cannot make its own food must eat to survive. It must “consume” its food! It is a consumer.

8. Why does this look more like a “cycle” than a chain?
Let’s discuss this one in detail.

9. In this food chain, what is the producer?
What is the first level consumer?
What is the second level consumer?
Is the polar bear the 3rd level consumer? Explain.

11. Food Webs
Food webs describe the organisms found in interconnecting food chains using pictures or words and arrows.
In other words, food webs are a bunch of food chains all together!
They describe the complex patterns of energy flow in an ecosystem by modeling who consumes whom or what.

12. Let’s follow a few food chains found in this food web.

14. Energy Pyramids
An energy pyramid shows the amount of energy that moves from one trophic level to another in a food chain.
The most energy is available at the producer level of the pyramid.
The availability of energy decreases as it moves up the energy pyramid.
Each level above only gets 10% of the energy from below

15. ENERGY PYRAMID
1 J
10 J
100 J
1,000 J
10,000 J

16. The most energy is at the producer level – the base of the pyramid.

19. The Energy Pyramid

20. Energy
Pyramid