Ecology

Energy Transfer

• All energy in an ecosystem comes from the sun• There are 2 ways energy moves. – As organisms eat other organisms, energy is stored. That

energy is used for life processes (movement, cellular respiration, reproduction) and released as heat.

– Energy is transferred from one organism to another when eaten.

Energy Transfer

Energy Transfer

Grass

Rabbits

Bobcats

Cougars Heat

Heat

Heat

100%

10%

1%

.1%

Percentage of initial energy transferred to the next level

Energy lost as heat (digestion,

movement, etc.)

Why is there not a percent on the decomposers box?

Because it depends on the energy of what is being decomposed.

KCal or amount of energy. Notice

that only 10% is being transferred

to each level.

Food Chain

• If an organism has an arrow going away from it, it is being eaten (giving energy to another organism).

• If an organism has an arrow going towards it, it is eating another organism (getting energy from that organism).

Ex: Plants Aphids Spiders Sparrows

Food Pyramid• Why is the bottom larger than the

top?

• Which level has the most energy and least energy?

• Label the trophic level with the most organisms and the least.

• 10% of energy is passed to each level, therefore fewer energy and fewer organisms.

It has more organisms and more energy

Food Webs

• If an organism has an arrow going away from it, it is being eaten.• If an organism has an arrow going towards it, it is eating another

organism. • If an organism has both arrows (one going away and one going

towards it), it is eating an organism and is being eaten by another organism.

• The organism that ONLY has arrows going away from it means:– It does not get energy from other organisms. It has to get energy from the

sun, therefore it is a producer.