Chapter 7 McGraw Hill Test

This diagram shows the transfer of energy in an aquatic ecosystem. Which population would increase if the blue whale population greatly decreased?

• krill

• crabs

• squid

• leopard seals

Refer to the table to answer the question. 

A student makes a table comparing primary and secondary ecological succession.  Which would best fit the space in the table labeled G?

• A glacier retreats, leaving bare rock behind

• 
  A hurricane causes a river to overflow its banks

• A group of trees are blown over in a wind storm

• A fishing company overfishes in a bay, decreasing the size of a fish population

The circle graphs display data about four ecosystems in an area. The different color segments represent different species found in the ecosystem. The size of the segments show the percentage of organisms that are of that species. Based on the information in the circle graphs, which ecosystem is most sustainable if a natural disaster strikes the area?

• a

• b

• c

• d

A student gathered data about the size of several populations in an ecosystem and organized the data into a table about population sizes in ecosystems.  In this ecosystem, lizards eat grasshoppers. Snakes eat mice. Grasshoppers and mice eat grass. Which of these would best explain the trend in population sizes in this ecosystem?

• Disease reduced the size of the mouse population.

• A species that eats snakes was introduced to the ecosystem.

• 
  A pesticide was used to control the size of the grasshopper population.

• 
  Most of the grass in the ecosystem was removed to make room for a parking lot.

Volcanic eruptions can send ash high into the air, blocking sunlight for long periods of time. How would food webs in an ecosystem change if a volcanic eruption caused a large reduction in sunlight for six months?

• All of the populations would decrease in size.

• The populations of producers would increase, but other populations would decrease.

• The populations of producers would decrease, but other populations would stay the same.

• The populations of consumers would decrease, but other populations would stay the same

What action could people take to help ecosystems provide more ecosystem services and resources?

• Introduce new species wherever possible.

• Work to maintain biodiversity in their local ecosystems.

• Identify the most common local species and focus on removing all other species.

• Increase the size of existing ecosystems by clearing land to allow them to expand.

Refer to the image to answer the question. The image shows secondary ecological succession that occurred in an area after a forest fire. Which statement is supported by evidence in the image?

• 
  Immediately following the forest fire, species diversity was low, and it remained low. 

• 
  Immediately following the forest fire, species diversity was high, and it remained high. 

• Immediately following the forest fire, species diversity was low, but then it increased over time.

• 
  Immediately following the forest fire, species diversity was high, and then it increased over time.

How would energy transfer and populations in a food web be affected if the number of producers in the ecosystem greatly decreased due to flooding in the area?

• First-level consumers would get plenty of energy to survive.

• The amount of energy available to first-level consumers would decrease.

• Population sizes of organisms that are consumers would stay about the same.

• 
  Second-level consumers would be able to get plenty of energy because they eat animals, not plants.

The image shows four stages in primary succession. Which statements are supported by evidence in the image? Select all correct answers.

• Species diversity is highest in stage number 2.

• Population diversity is highest in stage number 1.

• Most of the species in stage number 2 are pioneer species.

• The stability of the ecosystem is highest in stage number 4.

An ecosystem is constantly changing. However, most of the changes do not result in a large disruption of the balance between parts of the ecosystem. Which term describes this quality of ecosystems?

• carrying capacity

• dynamic equilibrium

• secondary succession

• eutrophication