Name ___________________________
Date __________________
Food Chains, Food Webs, and Population Levels
Instructions: Click on the links online but then fill out your answers on the printed copy.
1. Go to
http://www.ecokids.ca/pub/eco_info/topics/frogs/chain_reaction/play_chainreaction.cf
m
a. An _______________________ eats both plants and animals. People are in this group.
b. A ________________________ eats only meat. Two examples shown here are ________________ and
______________________.
c. An ________________________ eats only plants. Two examples shown here are _____________________
and _______________________.
d. Click on “Forest Food Chain” on the next page. Make the food chain, then test it. (Start with the sun even
though we don’t usually draw the sun in food chains. Remember that the energy for food chains comes
originally from the sun!) Draw the food chain here. (Just use words and arrows, not pictures.)
e. Remove the frog from the food chain in the simulation. Watch and read about what happens.
i. Does the grasshopper population increase (go up) or decrease (go down) at first? Why?
(Population means how many of that animal there are.)
ii. What happens to the grasshopper population eventually? Why?
iii. What will the snakes and hawks have to do? Why?
iv. What do you think would happen if all the grass suddenly disappeared from the original
food chain (for example, if the area was paved over for a parking lot)? Why?
f.
Repeat the activity for the “Arctic Food Chain”. This food chain would exist in the very cold water near the
North Pole. (Hints: The blob of green dots represents green algae, which is a producer. The algae uses
energy from the sun to make its own food. If you’ve ever seen pond scum, you were looking at algae.) Draw
the food chain here. (Just use words and arrows, not pictures.)
g. Remove the fish (the arctic cod) from the food chain in the simulation. Watch and read about what happens.
i. Why does the shrimp population at first increase but then later decrease and eventually
disappear? (Writing a thorough explanation will probably take a couple of sentences.)
ii. What will happen to the ringed seals? Why?
iii. What will happen to the polar bears? Why?
2. Go to the web site http://www.bbc.co.uk/schools/scienceclips/ages/10_11/interdependence.shtml
a. Click on each of the eight different living things in this woodland habitat. Then, click on each magnifying
glass and fill out the table below:
Woodland Ecosystem
Organism
What It Eats
What Eats and / or Kills It
Producer, Consumer, or
Decomposer?
Oak tree
Caterpillar
Snail
Thrush (small bird)
Fox
Barn Owl
Squirrel
Earthworm
b. Click on “Sorter 1” and make the food web. Notice that four different creatures all eat parts of the tree.
Draw the food web here. (Use words and arrows rather than pictures.)
c. Do the “Sorter 2” activity. Which animal in the diagram doesn’t fly, doesn’t have legs, and doesn’t have a
shell? _____________________
3. Go to this web site:
Then do the quiz.
http://www.harcourtschool.com/activity/food/food_menu.html
Do the activities and draw each completed food web. (Use words and arrows, not pictures.) Then answer
each question.
Meadow Food Web
Questions: If the rabbit population went way up, what do you think would happen to the fox population at first? Why?
What would happen to the rabbit population as a result? Why?
Then what would happen to the fox population? Why?
Arctic Food Web
(Hints: Diatoms are microscopic producers, a type of green algae. They can capture energy from the sun, like green
plants do. Krill are a kind of small shrimp, so they’re a type of animal.)
Question: What do you think would happen to the polar bear population if there were no more arctic wolves? Why?
Pond Food Web
(Hints: The green algae pictured here can make their own food using energy from the sun like green plants do. Every
other organism pictured in this food web is an animal.)
Questions: What is the producer in this ecosystem? ________________________
Which two consumers pictured here appear to be herbivores? (They eat the producer, but they don’t eat the animals.)
________________ and ________________
According to this food web, which fish is a carnivore? (It eats only animals. It doesn’t eat the producer directly.)
_____________________
Which fish is an omnivore? (It eats the producer and also eats animals.) ______________________
What is the top consumer (the top predator) in this ecosystem? (Hint: It eats organisms pictured here, but according to
this food web nothing in this ecosystem eats it. ) _________________________