Name: ________________________________ Block: ____
(Cold) Flowing-Water Food Web for Pennsylvania
A food chain shows the feeding relationships with one organism at each trophic level. A food web shows ALL of the feeding relationships within an ecosystem. Since all organisms are made of chemicals and chemicals store energy (in their bonds), think of organisms as “stored energy”. Therefore, food webs show how that energy flows through an ecosystem, between less influential and more influential organisms (Keytstone Species), to one top consumer (Apex Predator).
Objective: From the Populations List (bottom) of species and their feeding relationships, form a food web.
1. Include all producers and 4 insects
2. A.) Choose at least 1 organism from each of the other categories. B.) Write the names of your chosen
species on the food web. Pictures aren’t required. Then..,
3. Draw arrows from the organism being consumed to the organism consuming its energy.
Hint! Start at the bottom of the food web box with the producers.
Population List:
Producers: Algae, Water plants, and Detritous (dead organic matter) are the three common aquatic producers.
Crustaceans: Crayfish eats water plants, algae, detritous, worms, slugs and occasionally small fish.
Insects: Mosquito larvae eat algae and other microscopic organisms; Stoneflies eat detritous; Dragonflies eat other
insects, such as mayflies, caddisflies , midges, and some true flies (that suck fluid out of plants).
Mollusks: Freshwater clams and mussels are filter feeders of microscopic algae, bacteria, and protozoans; snails eat algae.
Fish: Trout (fish) eat insects, small fish, and crayfish; Small fish (Sculpin, Dace, & Darters) eat insects and algae; Eels eat
fish, insects, worms, and carrion (dead animals).
Amphibians: Green Frogs eat insects; Salamanders eat insects; Newts eat insect larvae, snails, & frog tadpoles.
Mammals: Beavers eat aquatic plants; Bears eat plants, small animals, and carrion (dead animal); Raccoons and Muskrats
both eat water plants, clams, crayfish, frogs, snails, and small fish.
Reptiles: Snapping Turtles eat plants, insects, and other small animals; Copperheads (snake) eat small rodents (mice and
voles), small fish, and carrion.
Birds: Cranes eat small fish, frogs, and crayfish; Eagles eat fish 90% of the time but also eat snakes, ducks, wading
birds, and rodents.
Name: ________________________________ Block: ____
QUESTIONS: (PA Flowing Water Food Web):
1. What do the arrows represent in a Food Web? In what direction should they point?
2. How many food chains are there in your food web?
3. Draw a food chain from your food web that has at least 3 levels. (Below is an example of a food chain with a 4th level – a Quaternary Consumer.)
Eagle (Quaternary
Consumer)
Crane (Tertiary Consumer)
(Secondary Consumer) Frog
Stonefly
Detritous (Primary
(Producer) Consumer)
4. Name the Tertiary Consumers in your food web.
5. Does your food web have any Quaternary Consumers – those above the Tertiary level? If so, name them. (Quaternary Consumer = 4th level of consumer)
6. Name the organisms that are parts of more than one trophic level. (Look for one organism that gets energy from another by more than one pathway.)
7. Name the top consumers – the “Apex Predator(s)”.
8. What organism(s) do you think are “Keystone Species” – are more important to the ecosystem? (Organize as prey or predators.) Explain your answer. (Hint: look at the number of food chains/arrows coming in to and going away from each organism.)
Prey:
Predators:
9. Is this list of species complete? (Add to it if you can.)
Flowing Water Aquatic Food Web
Eagle
Carrion (dead animals)
Crane Raccoon & Muskrat Bear
Copperhead Eel Trout
Beaver
Small Fish Crayfish
Green Frog Salamanders Newt
Snapping Turtle Dragonflies
True Flies
Clam/Mussel/Snail Mayfly/Caddisfly/Stonefly/Midge Mosquito larvae
Terrestrial
Plants
Algae Water Plants Detritous
Questions:
1. What do the arrows represent in a Food Web? In what direction should they point?
They show the flow of energy FROM comsumed TO the consumer.
2. How many food chains are there in your food web?
3. Draw one food chain from your food web that has at least 3 levels.
4. Name the Tertiary Consumers in your food web.
Crane, Raccoon, Muskrat, Bear, Eagle
5. Do you have any Quaternary Consumers – those above the Tertiary level? If so, name them.
Eagle
6. Name the organisms that are parts of more than one trophic level.
Eagle
7. Name the top “Apex” predator(s).
Eagle, Bear
8. What organism(s) do you think are “keystone species” – are more important to the ecosystem? Explain. (Hint: look at the number of food chains each org is in.)
Prey animals: Small fish, insects
Predators: Eagle , Trout
9. Is this list of species complete? Add to it if you can.