Ecology et.al.

Which statement best describes how bacteria recycle matter in an ecosystem?

• Bacteria are producers that create energy for second-order consumers.

• Bacteria produce toxins to prevent the growth of invasive species.

• Bacteria cause diseases that limit the reproduction of organisms in a population.

• Bacteria are decomposers that help to transfer organic material to the soil.

A farmer is struggling to control the population of a certain insect on his farm. After researching population control techniques, he discovers that a particular bird is a predator of this insect. The farmer purchases a number of these birds and releases them onto his farm. How might the farmer’s action most likely have a negative impact on the ecosystem?

• The birds will increase biodiversity of native plant species

• The birds will pollinate native species, increasing genetic variation.

• The birds will consume beneficial insects, as well as the pest species.

• The birds will mate with native birds and create a new species.

The flow of energy in a grassland ecosystem is shown. Based on the diagram, which two populations best represent trophic levels that receive the LEAST amount of the total energy provided to the ecosystem by the grass?

• Crickets and Sparrows

• Toads and Spiders

• Rabbits and Mice

• Hognose snakes and Owls

A food web representing a Gulf Coast ecosystem is shown. Based on this food web, which organism occupies multiple trophic levels?

• Canada

  Goose

• Eastern

  Cottontail

• Loggerhead

  Sea Turtle

• Sand

  Dollar

A partial Texas food web is shown. The populations of which organisms will most likely increase as a result of a disease that suddenly reduced the population of Texas horned lizards?

• Grasses and Ants

• Ants and Grasshoppers

• Grasshoppers and Texas Cottonmouths

• Texas Cottonmouths and Red-shouldered Hawks

A biomass pyramid of an ecosystem is shown. Which statement provides the best explanation for the difference in biomass of organisms found at each trophic level?

• Organisms at higher trophic levels have less energy available to them than organisms at lower trophic levels.

• Organisms at higher trophic levels require smaller habitats than organisms at lower trophic levels.

• Organisms at lower trophic levels provide less energy than organisms at higher trophic levels.

• Organisms at lower trophic levels outcompete organisms at higher trophic levels.

A small town in the piney woods of East Texas has a soccer field composed of native grasses. The soccer field is mowed once a week. What effect does continual mowing have on the ecology of the field?

• Mowing increases the likelihood of nonnative species displacing native species.

• Mowing increases the number of species found in the field.

• Mowing causes different types of communities to form across the field.

• Mowing maintains a low species diversity by inhibiting further succession.

Saprophytes are fungi that feed on dead and decomposing organisms. They secrete enzymes that digest components of cell walls, such as cellulose and lignin.

Which statement explains why these fungi are an important part of the biogeochemical cycle?

• Saprophytes transport nutrients through the xylem and phloem in autotrophs.

• Saprophytes perform gas exchange that assists the cellular activities of autotrophs.

• Saprophytes extract minerals from living tissue to recycle them back into the soil.

• Saprophytes return organic material to the soil for use by living organisms.

Based on this food web, which organisms are direct sources of energy for secondary consumers?

• Aphid

  Bird

  Rabbit

• Ladybug

  Fox

  Dragonfly

• Frog

  Butterfly

  Berries

• Mouse

  Snake

  Hawk

How might deforestation of a forest habitat directly affect populations of tree-dwelling animals? The deforestation will lead to–

• a shift of environmental conditions favoring prairie grass.

• a reduction of organisms that rely on the trees for protection.

• an influx of bird species that will occupy the trees.

• an increase in field mice, as they will camouflage easier.