Ecosystem Unit Review

In an ecosystem, grasshoppers are the main food source for opossums. The opossums are hunted by great horned owls and gray foxes. The population of opossums is reduced due to the spread of a disease.What effect will the decrease in the opossum population have on other organisms of the ecosystem?

• The gray fox population will increase.

• The grasshopper population will increase.

• The grass cover in the region will increase.

• The great horned owl population will increase.

Use the diagram which shows a simple grassland food web to answer the question. Which statement about the food web is true?

• Snakes feed on mice and lizards for food.

• Hawks feed on mice and snakes for food.

• Mice feed on grasses and lizards for food.

• Lizards feed on grasshoppers and rabbits for food.

A forest food web is shown in the diagram. Which statement describes what will happen if all the rabbits and squirrels die due to the spread of a disease?

• The population of owls will increase since the owls will feed on snakes only.

• The population of deer will decrease gradually because grass will dry out.

• The population of foxes will decrease because the foxes will not get enough food.

• The population of blueberries will increase because deer will stop feeding on them.

The diagram shows a food web of Chesapeake Bay. Which statement correctly explains the immediate effect of removing large fish from the ecosystem?

• There would be a sudden increase in the population of small fish.

• There would be a sudden increase in the population of sea ducks.

• There would be a sudden decrease in the population of bald eagles.

• There would be a sudden decrease in the population of ospreys.

A student made a table to categorize different organisms of a wetland food chain. Which organisms depend on the bladderwort for food?

• grass carp and mosquito

• alligator and heron

• heron and grass carp

• mosquito and alligator

Termites are organisms that break down dead and decaying wood matter. Which term best describes the role of termites in a food chain?

• carnivore

• consumer

• decomposer

• producer

The list shows how different organisms in a pond habitat obtain energy. Which food chain correctly represents the energy flow in the pond habitat?

• snail → catfish → heron → algae

• heron → catfish → snail → algae

• catfish → snail → algae → heron

• algae → snail → catfish → heron

Sharks must eat fish to survive in an ocean ecosystem. What role of the shark is described?

• Consumer

• decomposer

• prey

• producer

Which statement best explains how the role of an organism in a food chain is described?

• The role of an organism in a food chain is described by the organism’s size.

• The role of an organism in a food chain is described by the way it gets its energy.

• The role of an organism in a food chain is described by the organism’s lifespan.

• The role of an organism in a food chain is described by the speed of the organism.

What is the primary source of energy in most living communities?

• animal

• plant

• snail

• sun