1. How energy gets around and ecosystem.
Trophic Levels
How energy gets around and ecosystem.

2. Energy Transfer
Each time an organisms eats another organisms, energy transfer occurs.
Food chains, food webs, and trophic levels tell us how energy transfer occurs.
Each step in the chains or webs represent the transfer of energy.
Each time energy is transferred from one level to another, some energy is lost as heat and less energy is available for organisms at the next level.

3. Producer Makes it’s own food through photosynthesis.
Example: grasses, ferns, trees, algae

4. Herbivore Energy comes from producers.
Example: cow, sheep, deer, grasshoppers

5. Carnivore Get energy from other consumers.
Example: lions, hawks, spiders, sharks, whales

6. Omnivore Get energy from both producers and consumers
Example: bears, pigs, gorillas, rats, cockroaches, humans

7. Decomposer
Breaks down dead organisms in an ecosystem and returns nutrients to soil, water, and air.
Examples: fungi and bacteria

8. Food Chains
Food chain: sequence in which energy is transferred from one organism to another.

9. Food Webs
Show many feeding relationships that are possible in an ecosystem.

10. A terrestrial food chain
Quaternary consumers
Trophic Levels
Carnivore
Carnivore
Tertiary consumers
Carnivore
Carnivore
Secondary consumers
Carnivore
Carnivore
Primary consumers
Herbivore
Zooplankton
Producers
Plant
Phytoplankton
Figure 19.21
A terrestrial food chain
A marine food chain

11. Consumers Organisms which eat other organisms to obtain energy.
1. Primary Consumer: eats producers
2. Secondary Consumer: eats primary consumers.
3. Tertiary Consumer: eat secondary consumers
4. Quaternary Consumer: Eat Tertiary consumers

12. Figure 19.23 Quaternary, tertiary, and secondary consumers
Secondary and
primary consumers
Primary consumers
Producers (plants)
Figure 19.23

13. 10% Rule
90% of the energy at each trophic level is used to carry out functions of living.
Only 10% is available to the next trophic level.
amid/

14. What happens to energy as you go up trophic levels? Why?
Tertiary consumers
10 kcal
Secondary consumers
100 kcal
Primary consumers
1,000 kcal
Producers
10,000 kcal
Figure 19.26

15. https://www.youtube.com/watch?v=v6ubvEJ3KG M

17. Energy Pyramid/Bioaccumulation
Quaternary
Tertiary
Secondary
Primary
Producers

18. Energy Pyramid/Bioaccumulation
DDT easily becomes embedded into the fat stores of animals where it can remain for many years.  For example, in humans, the half-life of DDT is 6.3 years.
In soil, however, it has a half-life of up to 15 years!9  This long half-life gives small organisms a lot of time to take in and accumulate DDT, which can lead to potentially deadly concentrations.

19. Questions You Asked/Discussion
Why do we lose energy?
Since we can eat anything on the food chain does that mean we have the strongest immune system?
What would happen if we eat a lot of animals that are at the quaternary level?
Why aren’t we dying of all the toxins?
How much energy does a human get from a plant?
Is it possible to have more carnivores than producers?

20. Trophic Level Questions Pre-Ap
Create a food pyramid of all the trophic levels.
The producers begin with 200,000 kcal of stored energy. Show how the energy changes as it moves up the chain. Show bioaccumulation using 6 dots at the producer level.
In a grassland ecosystem there are lots of grasshoppers but only one hawk. Why is this?
What is bioaccumulation and how does it affect us?
Describe the differences between a food chain and a food web. Which is more accurate and why?

21. Trophic Level Questions On-Level
Draw an ecosystem food web with 12 organisms, include one organism from each trophic level. Label each trophic level and organism.
List and describe the differences between the five ways organisms get their energy. (producer, herbivore, etc.)
Describe the differences between a food chain and a food web. Which is more accurate and why?
How are omnivores similar to and different from carnivores?
Why are there fewer tertiary consumers than primary consumers?