1. Trophic Hierarchy in Ecosystems
1. Introduction
1a. Species are organized by what they eat and by what eats them.

2. Trophic Hierarchy in Ecosystems
2. Producers
2a. Producers (autotrophs) = plants and some bacteria.
The entry point for all of the energy used on Earth.

3. Trophic Hierarchy in Ecosystems
3. Heterotroph
3a. Heterotrophs (consumers) = any organism that eats organic compounds or other organisms to get its food.

4. Trophic Hierarchy in Ecosystems
4. Herbivors, Carnivores, and Omnivores
4a. Herbivores= Animals that
eat only plants.
4b. Carnivores= Animals that
only eat other animals.
4c. Omnivores= Animals that
eat both plants and animals.

5. Trophic Hierarchy in Ecosystems
5. Decomposers
5a. Decomposers= Organisms that feed on and break down dead organic material.
They recycle abiotic materials back into the ecosystem.

6. Trophic Hierarchy in Ecosystems
6. Trophic Pyramid
6a. Ecologists place organisms into different trophic levels (who’s eating who).

7. Trophic Hierarchy in Ecosystems
Level 1 Producers

8. Trophic Hierarchy in Ecosystems
Level 2
Primary Consumers
Aka First Order Consumers

9. Trophic Hierarchy in Ecosystems
Level 3
Secondary Consumers
Aka Second Order Consumers

10. Trophic Hierarchy in Ecosystems
Level 4
Tertiary Consumers
Aka Third Order Consumers

11. Trophic Hierarchy in Ecosystems
7. Matter vs. Energy
7a. Matter moves in cycles between abiotic and biotic realms.
7b. Energy moves in a one way path.

12. Trophic Hierarchy in Ecosystems
8. Movement of Energy
8a. On Earth, energy enters an ecosystem from the abiotic realm starting with the sun, and moves into the plants.
8b. The energy then moves into the trophic levels.

13. Trophic Hierarchy in Ecosystems
9. Grass and Rabbit Example
9a. Unlike matter, energy gets “worn out” each time it moves.
Example:
Grass captures energy from the sun during photosynthesis.
Rabbit eats grass but doesn’t get ALL of the grasses energy.
The grass used a lot of the energy from the sun to perform its own life functions (growing, repairing itself, etc…)

14. Trophic Hierarchy in Ecosystems
10. Ten% Rule
10a. This is known as the 10% Rule.
Approximately only 10% of the energy that enters a trophic level is available to the next level up.

15. Checkpoint
Calculate the % Energy passed on to each trophic level.

16. Assignment: Homework: Agenda: 3/19/13 Energy Pathways
Complete any unfinished assignments