1. Ecosystem Structure

2. Passing of Energy All Energy starts from the sun
Photosynthetic plants convert energy from the sun into food
The energy moves through the ecosystem as one organism eats another

3. Autotrophs / Producers
An organism that converts the sun’s energy (or inorganic substances) into food

4. Heterotrophs / Consumers
Organisms that obtain energy by eating other organism
Can eat plants or animals

5. Food Chains
A model of the flow of energy through organisms in a community
Flow of energy is shown by arrows

6. Transferred Energy
At each step in the food chain only 10% energy is passed to the organism
90% of the energy is lost in the form of HEAT
90%
HEAT

7. Trophic Levels Each step in the transfer of energy
Producers are 1st trophic level… they form the base of all food chains

8. Primary Consumers / Herbivores
Feed directly on producers
Make up the 2nd trophic level

9. Secondary & Tertiary Consumers / Carnivores
Eat only meat
Feed on primary & secondary consumers
Make up the 3rd and 4th trophic levels

10. Omnivores
Eat both producers and consumers

11. Scavengers
Consumer that feeds on the tissue of dead animals

12. Decomposers (recyclers)
Feed on wastes and dead organic matter from all trophic levels

13. Ecological Pyramid
Shows the relationship between producers & consumers in 3 ways:
Biomass
Energy
# of organisms

14. Biomass
Total mass of all organisms in a food chain or ecological community

15. Biomass Pyramid
There is less biomass as you move up trophic levels

16. Energy Pyramid & 10% Law Only 10% of energy is passed to next level
1st trophic level is important in determining the rest of the levels

17. # of organism pyramid
Population of each trophic level decreases as you move up the trophic levels

18. Food Web
Shows the interconnected food chains in a community or ecosystem
A lot of food chains together