1. Represent Ecosystems using Energy Pyramids
Unit 3 Notes Pt. II
Represent Ecosystems
using Energy Pyramids

2. Ecosystems
The size of populations change as a result of the interrelationships among organisms.
ALL organisms, including humans, are part of food webs and depend on each other!

3. Energy Pyramids
Each step on an energy pyramid is called a TROPHIC LEVEL. An organism relies on all the trophic levels below it in order to survive.
The higher up the pyramid you go, the fewer organisms belong in that group…WHY?...

4. The Energy Pyramid and the 10% Rule…
ALL organisms need energy to live (walk, breathe, fly, hunt, etc.).
All organisms use about 90% of their energy just to carry out daily functions.
10% Rule: The other 10% of energy gets stored in the organism and/or passed on to a predator.

5. The Energy Pyramid (the levels)
Producers: Get 100% of their energy from the Sun (photosynthesis).
Consumers: 10% of the prey’s energy is passed on to the predator. (Primary Consumers, Secondary Consumers, and Tertiary Consumers)

6. Example
Note the pyramid on the left. At the bottom are thousands of plankton. As you move up the pyramid, all those plankton end up supplying energy to just one shark!

7. Different Category of Consumer for Each Step
PRIMARY CONSUMER - these guys eat producers. Step 2 of the pyramid.
SECONDARY CONSUMER-
They eat the primary consumer. Carnivores. 3rd step.
TERTIARY CONSUMER-
They eat secondary consumers. Apex predator for many ecosystems, but not always.
Can keep going: Quarternary consumer, etc…

8. BIOMAGNIFICATION and BIOACCUMULATION
Organisms with long life spans get more and more toxins in their body as time goes on when they live in a polluted environment.
The effects of toxins gets multiplied for each step of the pyramid! Small organisms on the first trophic level might be safe, but the toxic accumulates in larger organisms.

10. Now you should be able to…
Describe organisms based on “Mode of Nutrition” (autotroph vs. heterotroph)
Describe different consumers based on what they eat (herbivore, carnivore, etc..)
Describe organisms by what trophic level they occupy in an ecosystem. (1st, 2nd..)
Describe the order in a food chain. (Producer, Primary consumer, 2ndary..)