1. At each level of the food chain, about 90% of the energy is lost in the form of heat.
The total energy passed from one level to the next is only about one-tenth of the energy received from the previous organism.
Therefore, as you move up the food chain, there is less energy available.

2. Rootbeer Activity The sun has one liter of rootbeer (energy) to give.
2. Of that, the plant gets one-tenth or 100 milliliters.
3. The mouse gets 10 milliliters from the plant.
4. The hawk gets 1 milliliter from the mouse.
5. When the hawk dies and is decomposed by the mushroom, the mushroom gets only one-tenth of a milliliter!

3. Sun has 1 liter (1000 ml)
Plant receives -100 ml
Plant has 100 ml
Mouse receives 10 ml
Mouse has 10 ml
Hawk Receives 1 ml
Hawk dies has 1 ml
Decomposers receive .1 ml

4. Ecologists study energy pyramids Energy Pyramids show the flow
of energy
through an
ecosystem

5. An energy pyramid from the Andrews
1 Kcal
3rd level
consumers
mostly carnivores &
some omnivores
10 Kcal
2nd level consumer
carnivores & omnivores
100 Kcal
1st level consumer
herbivores
1000 Kcal
Producers:
green plants make their own energy from sunlight
10,000 Kcal

6. move, digest, produce body heat, reproduce and escape from predators.
When an owl eats a flying squirrel it uses about 90% of the calories to live—
move, digest, produce body heat, reproduce and escape from predators.
When a frog eats a cricket or a cricket eats a plant, they use 90% of those calories to move, digest, produce body heat, reproduce and escape from predators.
0.01%
1 Kcal
0.1%
10 Kcal
100 Kcal 1%
When a cricket eats a plant it uses about 90% of the calories from that plant to move, digest, produce body heat, reproduce and escape from predators.
When a snake eats a cricket or a chipmunk, it uses about 90% of those calories to move, digest, produce body heat, reproduce and escape from predators.
When a top predator like a cougar, bear or spotted owl eats a flying squirrel, frog or salmon, it uses about 90% of those calories to move, digest, produce body heat and reproduce.
1000 Kcal
10%
100%
10,000 Kcal