1. Food Chains and Food Webs:
Energy Flow in Nature

2. The source of energy in EVERY ecosystem=
THE SUN!

3. Energy Roles
An organism’s energy role in an ecosystem may be that of a producer, consumer, or decomposer.

4. Producers An organism that can make its own food is a producer.
Also called Autotrophs (self feeders)
Source of all food in an ecosystem.
Capture energy from sunlight and stores it as food energy.

5. Consumers
Consumers are heterotrophs. They must eat things to get energy.
A food chain contains several kinds of consumers, each of which occupies a different trophic level.
Herbivore, carnivores, omnivores

6. Consumer Trophic Levels
Primary (1°) consumers eat producers (herbivores)
Secondary (2°) consumers eat primary consumers (carnivores)
Tertiary (3°) consumers eat secondary consumers (carnivores)
Scavengers are carnivores that feed on the bodies of dead organisms.
Omnivores eat plants and animals

7. Decomposers
Break down wastes and dead organisms and return the raw materials to the environment
Bacteria and fungi and scavengers

8. Food Chains
Series of events where one organism eats another and obtains energy.
First organism in chain is the producer.

9. PlanktonCrabSeaOrca
This is only one possible chain in a marine ecosystem.

10. Come up with an example to fill in the blocks of a food chain in two different ecosytems.

11. Food Webs Consists of many overlapping food chains in an ecosystem.
Some organisms may play more than one role by changing consumer levels.

12. What happens in a food web if one or more of the organisms disappear?

14. Energy Pyramid
A diagram that shows the amount of energy that moves from one feeding level to another in a food web.
Represented in a triangle with the most energy at the producer level.

16. Energy Loss and Use 10% of energy transferred to next higher level.
90% of energy is used by organisms’ life processes.
Due to energy loss, ecosystem cannot support many feeding levels.
Number of organisms at each level gets MUCH smalller

18. Biological Magnification-
Pollutants become MORE concentrated as they move up the food chain. (example- why eagles have thin egg shells and shark meat can be unsafe to eat)