1. Energy Movement in Ecosystems

2. Trophic Levels
Energy flow can easily be understood by using trophic levels.
These levels are organized by HOW organisms get their energy.
Autotrophs: create their own food
These organisms are known as producers
Heterotrophs: eat other organisms
AKA consumers

3. Trophic Levels First trophic level: producers (autotrophs)
Second trophic level: primary consumers
These organisms rely solely on the first trophic level for food.
Third trophic level: secondary consumers
They rely on the second trophic level organisms for their food. They eat these organisms who have eaten the autotrophs.
ETC…

4. Top Consumer
3rd trophic level
2nd trophic level
1st trophic level

5. Energy & Food Chains
Every organism in a particular ecosystem provides energy for other organisms.
Food Chains show step by step the flow of energy (who eats who).
Those at the top of a food chain are called the top carnivore (nothing eats them while they are alive).
Trophic levels and positions on the food chain are very closely linked.

6. Food Web
The reality of nature is that most organisms are part of many different food chains. This blending of food chains is known as a food web where organisms that may not share a common food chain are linked together based on who eats who.

9. The Transfer of Energy
Every time energy is transferred within an ecosystem some of the energy changes form and is no longer available for transfer.
The further along the food chain you travel the less energy that is available to be consumed.
Where does the lost energy go?
It is used by the organism to grow/live.

10. Thermodynamics
Another limit that energy transfer faces is the laws of thermodynamics (the study of energy transformations)
1st Law: Energy can be transformed but not created or destroyed.
2nd Law: in any energy transformation some of the energy becomes unusable.

11. Understanding Concepts
Answer questions 1 to 9 on page 39