Trophic Levels/Energy Pyramid
Trophic Levels = describe the position that an organism occupies in a food chain - what it eats
and what eats it.
BMIs: Write the names of the BMIs that you collected and identified at the Cedar River in the
appropriate place on the pyramid (primary consumers/herbivores & Secondary
consumers/predators).
FISH: Salmon/Trout that eat BMIs
Consumers (heterotrophs): organisms that feed on other organisms. Includes herbivores (eat
only plants or algae) and predators (eat other animals).
Producers: (autotrophs) utilize energy from the sun and nutrients from the abiotic environment
(carbon dioxide from the air or water, other nutrients from the soil or water) to perform
photosynthesis and grow. Producers are generally green plants & algae.
Decomposers (detritivores): utilize energy from wastes or dead plants and animals, and so
complete the cycle by returning nutrients to the soil or water, and carbon dioxide to the air and
water. Some BMIs (shredders) help breakdown larger pieces of dead leaves & twigs into fine
particles, which in turn provide food for other BMIs (collectors).
Resources:
Spineless Ones (p. 86-95)
Stream Bugs of King County (p. 101-102)
http://dnr.metrokc.gov/wlr/waterres/Bugs/role.htm
Note: some energy
pyramids show
Decomposers off to
the side with arrows
coming from each
level of pyramid. Your
choice!
Include labeled pictures
representing the BMIs the
class caught, their feeding
group and their pollution
tolerance values.
Tertiary Consumers
Freeliving
Caddisfly
PTV = 2
Decomposers
Secondary Consumers
(Predators)
Stonefly
PTV= 1
Mayfly
PTV = 2
Primary Consumers
(herbivores)
Producers
Casemaker
Caddisfly
PTV = 2