1. Trophic Levels, Energy transfer and Pyramids

2. Trophic Levels – is the position an organism occupies in a food chain
Trophic Levels – is the position an organism occupies in a food chain. It refers to food or feeding.

3. Food Chain

4. Food Chains
The energy flow from one trophic level to the other is know as a food chain
Producers are at the first ENERGY LEVEL
Primary Consumers are the SECOND ENERGY LEVEL
Secondary consumers are at the THIRD ENERGY LEVEL

5. Trophic Levels (feeding levels)3 2 1

6. Food webs are multiple food chains.

7. Food Webs
Food webs show ALTERNATIVE PATHWAYS other possible pathways through which an organism can obtain energy

8. Food webs

9. 1st 2nd producer Grass Mouse Primary consumer Grasshopper Frog Owl
Energy Level
Producer, primary consumer, secondary consumer, tertiary consumer?
Grass
Mouse
Grasshopper
Frog
Owl
Hawk
1st
producer
2nd
Primary consumer

10. Secondary and tertiary consumer
Energy Level
Producer, primary consumer, secondary consumer, tertiary consumer
Grass
1st
Producer
Mouse
2nd
Primary consumer
Grasshopper
Frog
3rd
Secondary consumer
Owl
3rd and 4th
Secondary and tertiary consumer
Hawk

12. Energy lost from chain “link” to “link” is significant!
Transfer of Energy
Energy lost from chain “link” to “link” is significant!

13. from grass to sheep, loss is about 90%!
HEAT
90%
HEAT
90%
100% Energy Available
10% Original Energy!
1% Original Energy!

14. Energy lost from one trophic level (energy level) to the next level can be represented by a pyramid
4⁰ CONSUMERS
3 CONSUMERS
2 CONSUMERS
1 CONSUMERS
PRODUCERS

15. Each level above only gets 10% of the energy from below
Ex: 10,000 J of producers (plants) only give 10% of energy to primary consumers
1,000 J to primary consumers (snails, minnows, dragonflies)
100 J to secondary consumers (small fish)
10 J to tertiary consumers (big fish)
1 J to quaternary consumers (fish hawk)

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

18. Usually no more than 5 trophic levels since 6th level would have very little energy to keep it alive

19. Ecological Pyramid
Which level has the most energy?
Which level has the most organisms?
Which level has the least organisms?
Which level has the least energy?