1. Trophic Levels:

2. Trophic Levels:
= an organism’s position in the food chain... …what it eats and what eats it...

3. What the “Levels?”
Primary producers  = producers / autotrophs
1◦ = Primary consumers eat primary producers: herbivores
2◦ = Secondary consumers eat primary consumers: carnivores and omnivores 
3◦ = Tertiary consumers eat secondary consumers
4◦ = Quaternary consumers eat tertiary consumers
Food chains "end" with top predators, animals that have little or no natural enemies

4. Place a “1°” under any consumer that can act as a primary consumer…
Remember this?
Place a “1°” under any consumer that can act as a primary consumer…
A “2°” under any consumer that can act as a secondary consumer…
A “3°” for tertiary consumers…
And a “4°” for quaternary consumers…
Label the ‘primary producer’
Maple
Millipede
Salamander
Snake
Hawk

5. 1° 3° 4° Primary Producer Primary Consumer 2° Secondary Consumer
Maple
Millipede
Salamander
Snake
Hawk
Primary
Producer 1°
Primary
Consumer 2°
Secondary
Consumer 3°
Tertiary
Consumer 4°
Quaternary
Consumer

6. Examples of Feeding Relationships

8. From which trophic level do secondary consumers get their energy?
Explain how the energy from the sun gets passed to ALL organisms in a food web.

9. The amount of energy in an ecosystem can be shown using a pyramid which illustrates the amounts of energy within each trophic level
Draw this!
Least energy
Most energy

10. Why do you think there is such a big difference?
Energy Pyramid:
Lets look at the number of species in the lower trophic levels and compare it with the number of species in higher trophic levels.
Why do you think there is such a big difference?

11. Think about how many individual insects could be supported by one individual tree…
We usually compare trophic levels by how much total energy the trophic level contains rather than the total number of organisms in a trophic level

12. Least energy
Most energy
There really is no limit to the numbers of trophic levels that a food chain can support….but, only part of the energy stored in one trophic level is passed on to the next level…it takes energy to sustain life!

13. 10% Rule in Ecology….
~10% of the energy in one trophic level is passed to the next trophic level

14. 10%
90% lost as heat

15. 10%
90% lost as heat

16. 10%
90% lost as heat

17. How much energy is left at each level?
1000 Cal
? Cal

18. 1000 Cal
100 Cal
10 Cal
1 Cal
9 Cal as heat
90 Cal as heat
900 Cal as heat

19. 10% Rule Question
Why do you think only 10% of the total energy from 1 trophic level is passed to the next?

20. Why do you think only 10% of the total energy from 1 trophic level is passed to the next? 3 reasons:
Energy is “used up” for daily life activities
Not all organisms that die are eaten by animals in the next trophic level
Not all parts of an organism are eaten and digested for energy

21. Review about energy flow:
2. How does the amount of energy change as it passes through an ecosystem?
3. What is the source for all energy in an ecosystem?

22. Answers!
2. How does the amount of energy change as it passes through an ecosystem?
The amount of available energy decreases as it passes to higher trophic levels
3. What is the source for all energy in an ecosystem?
All energy in an ecosystem can be traced back to the sun