5.9c

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 live 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?

• 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.

The nesting habits of 4 types of bird 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?

• Baltimore oriole
• Barn swallow
• Downy woodpecker
• Belted kingfisher

Wild Texas hogs, similar to the one shown, 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?

• 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.

The picture shows a type of plant called kudzu.  Kudzu is a fast-growing Asian vie that was introduced into the United States.  Kudzu quickly uses available resources and can completely cover the plants in the area. What effect does the rapid growth of kudzu most likely have on a n ecosystem?

• 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.

The picture shows a frog in a pond containing duckweed.  Facts about Duckweed: 
*Duckweed is a small plant that grows in water. 
*Many waterbirds depend on duckweed for food.
*Duckweed can reproduce rapidly in water that is rich in the nutrients used in agriculture.
Which of these human activities would most likely cause an overgrowth of duckweed in a pond environment?

• Gradually introducing geese into the pond.
• Fishing in the pond as recreation.
• Planting trees in nearby forests.
• Heavily fertilizing nearby farm fields.