Food and Energy

Ecology II

Food Chain

Diagram that shows how matter and energy move

through an ecosystem

Direction of Arrow

“” means “gets eaten by”, shows the direction energy

flows

Algae zooplankton small fish heron alligator

Trophic Level

Feeding level of organism, the energy level

Each organism represents a trophic level

Organisms can occupy more than one trophic level if they eat

more than 1 type of food

Food Web

Multiple food chains with organisms occupying multiple

trophic levels

Arrow

shows

the flow

of energy

Most energy is at the

bottom

2 2

Food chains and food webs

They represent the ways matter and energy can be

transferred in an ecosystem

#1 Energy source is …

SUN!

Sunlight is what drives photosynthesis

How do we show how energy is used in an

ecosystem?

Use ecological pyramid as a model to show the energy

flow

Rule of Energy

As you increase trophic levels you lose energy. Only 10%

of energy is transferred from one organism to the next.

5th trophic level

4th trophic level

3rd trophic level

2nd trophic level

1st trophic level

Scavengers &

Decomposers = 4th heterotroph

Carnivore that eats

carnivores = 3rd heterotroph

= 2nd heterotroph

= 1st heterotroph

= autotroph

Carnivore that eats

herbivore

Herbivore eats plants

Plants

3rd consumer

2nd consumer

1st consumer

producer

1000

1

10

100

•Only 10% energy

goes up

•Rest is used for

movement,

metabolism, heat