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ECO: Food Webs - What happens if .....

Total questions: 15

Worksheet time: 35mins

Name
Class
Date
1.
Which organism do the owl and the weasel compete for in the food web?
a)
Hawk
b)
Spider
c)
Grasshopper
d)
Shrew
2.
What might happen if you remove a primary consumer from the ecosystem?
a)
There would be more food for secondary consumers.
b)
The number of primary consumers would increase.
c)
The number of plants would increase.
d)
The number of secondary consumers would increase.
3.

Which of the following would be the most likely effect, if there were a sudden increase in the cricket population?

a)

There would be a decrease in the small bird population.

b)

There would be a decrease in the grass/flowers population.

c)

There would be a decrease in the mice population.

d)

There would be an increase in the grass/flowers population.

4.
Recently, a family of bobcats moved into an area with a large rabbit population. What changes may occur in the ecosystem?
a)
The rabbit population may increase
b)
The rabbit population may decrease
c)
The rabbit population may increase first, then decrease
d)
The rabbit population will remain the same
5.
What may happen if the snowshoe hare was removed from the food web pictured?
a)
The insects in the habitat would increase.
b)
The shrew population would decrease due to being only hawk food source.
c)
The willow tree population would decrease.
d)
Foxes would dies due to no food source. 
6.

How would the removal of earthworms from the food chain affect the other organisms?

a)

The number of bass will increase.

b)

The number of crayfish will decrease.

c)

The crayfish will get their energy directly from the sun.

d)

The number of bass and ospreys (bird) will increase.

7.

Suppose that a new predator of the rabbit migrated to this ecosystem. What is the most likely initial effect on the other organisms?

a)

More competition among the mice for food

b)

More competition among the hawks for food

c)

Less competition among snakes for food

d)

Less grass available for food

8.

For the food chain shown, which of the following changes would have the most severe consequences?

a)

a drastic decrease in rainfall, causing a drought

b)

the poaching of predatory hawks by game hunters

c)

the introduction of a second predator that eats field mice

d)

a parasitic infestation that reduces the cricket population

9.

The picture provided shows an ocean bay food chain. Sea otters move into the ocean bay. They eat all of the sea urchins. This change will cause the

a)

kelp to have less food.

b)

crabs to have more food.

c)

sea ducks to have less food.

d)

arctic foxes to have more food.

10.

The picture shows an energy pyramid. What will most likely happen to the foxes and the wolves if the rabbits are removed?

a)

The foxes will eat more wolves.

b)

The foxes will eat fewer wolves.

c)

There will be more foxes and wolves.

d)

There will be fewer foxes and wolves.

11.

A chemical pesticide was applied to an area of this ecosystem by a landowner to control the mouse population. There was a decrease in the mouse population due to the presence of this pesticide. Which one of the following would most likely occur due to this change in the ecosystem?

a)

The amount of grass would decrease.

b)

The snake population would increase.

c)

The rabbit food supply would increase.

d)

The snake food supply would increase.

12.

The picture shows the energy flow through a meadow community. Which of the following would most likely occur to the populations within the community of organisms immediately after a wildfire burns the environment?

a)

Hawks would increase and foxes would increase.

b)

Hawks would decrease and foxes would increase.

c)

Meadow plants would increase and rabbits would decrease.

d)

Meadow plants would decrease and rabbits would decrease.

13.
Recently, a family of bobcats moved into an area with a large rabbit population. What changes may occur in the ecosystem?
a)
The rabbit population may increase
b)
The rabbit population may decrease
c)
The rabbit population may increase first, then decrease
d)
The rabbit population will remain the same
14.
A population of mice lives in a barn community. A cat population has just joined the community. What will happen?
a)
Mouse and cat populations both go up?
b)
Mouse and cat populations both go down
c)
Mouse population goes down as cat population goes up
d)
Mouse population goes up as cat population goes down
15.

What would happen to the blue whale population if the krill population went extinct?

a)

the blue whale population eats other things in the food web

b)

the blue whale population would increase

c)

The blue whale population would remain the same.

d)

the blue whale population would also decrease