Food Chains, Webs, & Pyramids

How Energy Flows in an Ecosystem

FOOD CHAINSProducers, Consumers, and…

Producers

• A group of organisms that produce their own food using sunlight to convert water & CO2 into glucose (food)– Also called autotrophs– Examples: plants & algae

Producers/Autotrophs

Consumers

• Organisms that consume other organisms in order to live– Also called heterotrophs because they

cannot make their own food– Examples: sharks, mushrooms, seals,

cows

Consumers/Heterotrophs

Primary Consumers

• Eat plants– Examples: giraffes, rabbits

Primary Consumers

Secondary Consumers

• Eat primary consumers (eat plant eaters)– Examples: lions, tigers, bears (oh my!)

Secondary Consumers

Tertiary Consumers

• Eat secondary consumers (eats meat eaters)– Examples: cougars, bears, wolves– Not always present in the food chain

Tertiary Consumers

Scavengers

• Feed on the tissue of dead organisms (both plants and animals)– Examples: crows, vultures, shrimp

Scavengers

Decomposers

• Absorb any dead material and break it down into simple nutrients or fertilizers– Examples: bacteria & mushrooms

Decomposers

Food Chain

• A diagram that shows how energy in food flows from one organism to another– Arrow points toward whichever organism

is receiving the energy

Food Chain

Links in the Chain

• Every organism depends on the other organisms– Example: If all of the grass died, the

grasshopper would starve to death causing the snake and the hawk to starve to death until eventually even the fungi do not have anything to feed on

FOOD WEBSChains + Chains =

Food Webs

• A diagram that shows the feeding relationships between organisms in an ecosystem–Multiple relationships composed of

multiple food chains–Most organisms eat more than one

organism–Much more complex and accurate

Food Web

ENERGY PYRAMIDSHow energy flows…

Energy Pyramid

• A triangular diagram that shows an ecosystem’s loss of energy– Results as energy passes through the

ecosystem’s food chain/web– Shows the number of organisms and

amount of matter/energy available at each level

– Decreases at each level because most energy is lost as heat waste

The End!