Aquatic Food Webs
by Jennifer Rogers
- Introduce Aquatics (freshwater)
- Have students list organisms from an aquatic area nearby
- Review what is to be covered: food webs, the organisms and how they relate
Organisms in a food web
Role of organisms:
- Have students use index cards to name one animal that depends on the
other from the list compiled in the introduction
- Read aloud results-explain they just designed a simple food chain
- Food chain-feeding relationships among organisms
- Brief introduction of aquatic invertebrates if not mentioned in lists
- Shredders, grazers, gathering collectors, filter feeders
- What are producers?
- What are decomposers?
- What are consumers? (herbivores, carnivores, omnivores, parasites, detritovores)
- Pass out examples (specimens)
How do they interconnect?
- Discuss when food chains interconnect they become a food web-Have students
break into groups of 3 to5 and on overhead paper create a food web using
organisms showed in class
- Share student food webs
- Put up an example of an actual food web-pointing out organisms
- Briefly discuss trophic levels in a food web and discuss how it narrows
as you move up in the food chain
- Go over key points: what have we learned?
- Have students attempt to classify a couple of the specimens. Where does
it belong in a food web?
Aquatic Invertebrate trivia:
- Shredders-feed on organic matter by shredding, chewing then digesting
Ex. Stonefly, cranefly, caddisfly
-feed on algae on rocks/hug the bottom
Ex. Caddisfly, mayflies
- Gatherers-roam the stream collecting deposits from rocks
- Filter collectors-use a "net" to catch small animals/invertebrates