Food Chains and Food Webs: Energy Flow in Nature

The source of energy in EVERY ecosystem= THE SUN!

Trophic Levels The number of steps from the start of a food chain. -troph=“nutrient”

Producers makes its own food energy from sunlight is a producer. (Photosynthesis) Also called Autotrophs (self feeders) Source of all food in an ecosystem.

Consumers Consumers are heterotrophs. They must eat things to get energy. Herbivore, carnivores, omnivores

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

Decomposers Break down wastes and dead organisms and return the raw materials to SOIL Bacteria and fungi and scavengers

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

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

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

Food Webs Consists of many overlapping food chains Some organisms may play more than one role by changing trophic levels.

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

Energy Pyramid A diagram that shows the amount of energy that moves from one feeding level to another in a food web. Most energy at the producer level. (bottom)

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

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)