UNIT4: Interactions in Ecosystems

Did the lemming population begin to increase, decrease, or stay the same in 1990? (2 points)

• Increase

• Decrease

• Stay the Same

Frogs eat grasshoppers. Grasshoppers eat grass. If the amount of grass decreases, what will happen to the population of frogs?

• Population Increase

• Population Decrease

• Populations stay the same

• It is not possible to tell

frogs are a predator, and grasshoppers are their prey. If the number of frogs increases, what happens to the number of grasshoppers?

• Population Increases

• Population Decreases

• Population Stays the Same

• It is not possible to tell

In an ecosystem, wolves eat deer and rabbits. If bears are introduced to the ecosystem, and the number of deer and rabbits eaten by wolves stays the same, what will happen to the population of plants?

• The amount of plants will increase

• The amount of plants will decrease until they are all gone

• The amount of plants will stay the same

• The amount of plants will decrease a little

What pattern in the weasel population begins during each of the years that followed 1988, 1992, 1996, and 2000?

• Increase

• Decrease

• Stay the Same

A honey-badger digs the ground tunnels in search for snakes. In one occasion, the badger finds a snake and competes with it. The badger leaves scratches and bite marks on the snake before it escapes. After twenty-four hours the snake dies. What is the limiting factor to the snake?

• Predator-Prey Relationships (density dependent)

• Competition for Food (density dependent)

• Temperature (density independent)

• Weather (density independent)

What happens to the amount of rainfall from 1976 to 1977?

• Increase

• Decrease

• Stay the same

If the population of a certain predator increases, there is often _______ its prey

• a decrease the population of
• an increase of the population of 
• great news for its prey of
• no  impact found on

"Introducing a new species to an ecosystem is too small of a change to have a large effect on the other populations in an ecosystem." Is this true?

• I agree with this claim. Small changes in an ecosystem are unlikely to affect other populations.

• My knowledge supports this claim. Small changes in an ecosystem can affect other populations, but only in small ways.

• I disagree with this claim. Small changes in an ecosystem can have large effects on another population, but only if the population is directly affected by the change.

• I disagree with this claim. Small changes in an ecosystem can have large effects on many populations throughout an ecosystem.

What happens to the population of finches from 1976 to 1977?

• Increase

• Decrease

• Stay the same