Food Chains and Ecosystems

Grade 3 Science Worksheet - Challenge Me

Circle the answer.

1. 1.

   In grass → grasshopper → frog → hawk, if the frogs disappear, what happens to the grasshoppers at first?

   • they increase, because fewer frogs eat them
   • they decrease, because hawks eat them instead
   • they decrease, because they have less grass
   • they stay the same, because they eat grass
2. 2.

   In grass → grasshopper → frog → hawk, what happens to the grass if the grasshoppers increase a lot?

   • it stays the same, because grass makes its own food
   • it decreases, because more of it gets eaten
   • it increases, because hawks protect it
   • it increases, because frogs eat less
3. 3.

   In a meadow, rabbits and mice both eat grass and seeds. Hawks eat rabbits and mice. If the rabbits leave, why might the hawks still survive?

   • the hawks can start eating grass
   • the mice will make food for hawks
   • the hawks need no food for a while
   • the hawks can still eat mice
4. 4.

   A wetland is drained to build houses. Which animal would most likely not survive there anymore?

   • a frog that lays eggs in water
   • a pigeon that nests on roofs
   • a squirrel that lives in trees
   • an ant that lives in soil
5. 5.

   Which food chain shows energy moving through four living things in the right order?

   • algae → big fish → small fish → heron
   • small fish → algae → big fish → heron
   • heron → big fish → small fish → algae
   • algae → small fish → big fish → heron
6. 6.

   A farmer sprays a field and most insects die. Birds in the field eat insects. What will most likely happen to the birds?

   • fewer birds can live there
   • more birds will move there
   • the number of birds will not change
   • the birds will make their own food
7. 7.

   Deer eat young trees. Wolves eat deer. Wolves return to a forest after many years. What happens to the young trees?

   • more young trees grow, because there are fewer deer
   • nothing changes for the trees
   • the young trees stop growing
   • fewer young trees grow, because wolves eat trees
8. 8.

   Sea otters eat sea urchins, and sea urchins eat kelp. If the sea otters disappear, what happens to the kelp forest?

   • it stays the same, because kelp makes its own food
   • it grows, because the urchins leave
   • it shrinks, because more urchins eat the kelp
   • it grows, because otters no longer eat kelp
9. 9.

   A long drought dries up a small pond until no water is left. What will most likely happen to the fish that lived in it?

   • they move to the grass and eat seeds
   • they die, because their water habitat is gone
   • they grow larger, because there is less water
   • they swim away to find a bigger pond
10. 10.

    In a pond, ducks and fish both eat insects. If the ducks increase, what might happen to the fish?

    • they will make their own food
    • they will start eating the ducks
    • they will have more insects to eat
    • they may have fewer insects to eat