1. Energy Flow in Ecosystems
How Ecosystems Work
Energy Flow in Ecosystems

2. Energy Transfer

3. Food Chains

4. Energy flows in one direction
from sun or inorganic molecules
to autotrophs
to heterotrophs

5. Energy Transfer
Each time an organism eats another organism, an energy transfer occurs.
This transfer of energy can be traced by studying food chains, food webs, and trophic levels.

6. Food Chains
Series of steps in which organisms transfer energy by eating and being eaten

7. Arrows show the flow of energy

9. A food chain shows the transfer of energy through an ecosystem.
Arrows show how energy moves.

10. Food Chain in an Antarctic Ecosystem

11. Food webs show all the feeding relationships in an ecosystem
Food webs show all the feeding relationships in an ecosystem. They contain many food chains.

14. Each step of a food web or food chain is a trophic level.
Consumers depend on the trophic level below for their energy.
2nd and higher levels – consumers
1st trophic level – producers

15. Trophic Relationships
4th Level Consumers (top predators)
3rd Level Consumers
2nd Level Consumers
1st Level Consumers (herbivores)
Autotrophs

18. The End