Staar Science Ecosystems

Fertilizers used on farms near the coast can be carried to the ocean when runoff occurs during rain showers. These fertilizers can decrease the populations of fish and shellfish. Which other populations most likely decrease as a result? (5.9C)

• Organisms that eat algae

• Organisms that live on farms

• Organisms that eat fish and shellfish

• All of these

Data for four animal populations in a wooded area were collected before and after a shopping mall was constructed near the area. The graph shows changes in the populations. Which animal's food sources most likely increased after the mall opened? (5.9C)

• Snakes, squirrels, and raccoons

• Squirrels only

• Snakes, squirrels, and deer

• Raccoons only

The nesting habits of four types of birds are described in the table. If all the dead branches and dying trees in a wooded area are removed, which bird's nesting habit would be most affected? (5.9C)

• Baltimore oriole

• Barn swallow

• Downy woodpecker

• Belted kingfisher

Prairie dogs eat plants and dig underground tunnels. Prairie dog tunnels help break up hard prairie soils, and the animals' waste adds nutrients to the soil. In the past, large groups of prairie dogs lived in many parts of the U.S. Great Plains, but people have destroyed most of these colonies. Which of these will most likely happen when prairie dogs are removed from an area? (5.9C)

• The population of predators that eat prairie dogs will decrease.

• The population of plants that prairie dogs eat will decrease.

• The nutrients in the soil will increase.

• The number of underground tunnels will increase.

Wild Texas hogs, similar to the one shown here, are descended from hogs brought here from other countries. These wild hogs eat many different kinds of foods, including plants, fungi, and insects. Besides being very destructive to the habitats of other animals, how do wild hogs most likely harm other animals? (5.9C)

• By competing with other animals for food

• By moving slower than most other animals

• By causing other animals to reproduce more

• By eating foods that no other animals eat

This picture shows a type of plant called kudzu. Kudzu is a fast-growing Asian vine that was introdued into the United States. Kudzu quickly uses available resources and can completely cover the plants in an area. What effect does the rapid growth of kudzu most likely have on an ecosystem? (5.9C)

• The variety of native plants decreases.

• The water supply in the area increases.

• Weather patterns in the area change.

• The number of other plants increases.