1. Feeding Relationships
How does energy flow through living systems?
Energy flows through an ecosystem in one direction, from the sun or inorganic compounds to autotrophs (producers) and then to various heterotrophs (consumers).
Energy cannot be recycled.

2. Vocabulary
Food chain
The energy stored by producers can be passed through an ecosystem along a food chain.
Food chain.- a series of steps in which organisms transfer energy by eating and being eaten.
In most ecosystems, feeding relationships are more complex than food chains.

3. Vocabulary
Food web
When the feeding relationships among the various organisms in a ecosystem form a network of complex interactions it is called a food web.
A food web is made of many food chains.

5. sun
tree
mouse
mushroom
snake
hawk

6. Each step in a food chain or food web is called a trophic level.
Vocabulary
Trophic level
Each step in a food chain or food web is called a trophic level.
Producers make the first trophic level and consumers make up the second, third or higher trophic levels.
Each consumer depends on the trophic level below it for energy.

7. All organisms need energy to live. They get it in different ways.
ENERGY FLOW
All organisms need energy to live.
They get it in different ways.
The sun is the original, main source or energy for life on Earth.

8. Energy is transferred in only one direction
sun  producer  1° consumer  2° consumer  3° consumer  decomposer  producer
Only 10% of the energy at one trophic level is transferred to the next trophic level.
10% is stored in living tissue (biomass)
90% used to keep the organism alive (respiration, movement, heat, etc.)
How efficient is the transfer of energy among organisms in an ecosystem?
Vocabulary
biomass