Ecosystems MCQs
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Which of the following probably contains the highest concentration of toxic pollutants (biological magnification)?
- A. hawk
- B. snake
- C. shrew
- D. grasshopper
- Correct Answer: Option A
Which of the following is a tertiary consumer?
- A. hawk
- B. snake
- C. shrew
- D. grasshopper
- Correct Answer: Option B
Which of the following has the smallest biomass?
- A. hawk
- B. snake
- C. shrew
- D. grasshopper
- Correct Answer: Option A
The high levels of pesticides found in birds of prey is an example of
- A. eutrophication.
- B. predation
- C. biological magnification.
- D. the green world hypothesis.
- Correct Answer: Option C
Human-induced modifications of the nitrogen cycle can result in
- A. eutrophication of adjacent wetlands.
- B. decreased availability of fixed nitrogen to primary producers.
- C. accumulation of toxic levels of N2 in groundwater.
- D. extermination of nitrogen-fixing bacteria on agricultural lands.
- Correct Answer: Option A
Some global warming models predict that, if permafrost in the tundra regions in the northern hemisphere melts, atmospheric CO2 levels will increase. Which of the following statements best explains this prediction?
- A. The heat released by the melting of the ice on such a vast scale will cause atmospheric CO2 saturation levels to increase.
- B. All of the tundra producers will die if the permafrost melts, and because the tundra regions are vast in the northern hemisphere the tundra plants will not take part in photosynthetic removal of atmospheric CO2.
- C. CO2 tied up in the permafrost ice will be released during a thaw.
- D. All of the undecayed organic material would be subject to decomposition following a thaw, which would lead to incredible increase in global cellular respiration, and add to atmospheric CO2.
- Correct Answer: Option D
In terms of nutrient cycling, why does timber harvesting in a temperate forest cause less ecological devastation than timber harvesting in tropical rain forests?
- A. Temperate forest tree species require fewer nutrients to survive than their tropical counterpart species, so a harvest removes fewer nutrients from the temperate ecosystem. C) D)
- B. There are far fewer decomposers in tropical rain forests so turning organic matter into usable nutrients is a slower process than in temperate forest ecosystems.
- C. The warmer temperatures in the tropics influence rain forest species to assimilate nutrients more slowly, so tropical reforestation is much slower than temperate reforestation.
- D. Typical harvests remove up to 75% of the nutrients in the woody trunks of tropical rain forest trees, leaving nutrient-impoverished soils behind.
- Correct Answer: Option D
Which of the following properly links the nutrient to its reservoir?
- A. Nitrogen--ionic nitrogen in the soil
- B. Water--atmospheric water vapor
- C. Carbon--dissolved CO2 in aquatic ecosystems
- D. Phosphorous--sedimentary rocks
- Correct Answer: Option D
If you were tracking a nutrient molecule through an ecosystem, which of the following statements would you expect to verify?
- A. Molecules move through all ecosystems at the same constant rate, as the laws of physics would predict.
- B. Because of the liquid nature of the aquatic ecosystem, nutrient molecules move through it more rapidly than forest ecosystems.
- C. Vertical mixing is essential for high productivity in aquatic ecosystems.
- D. Most nutrient molecules leave an ecosystem, but are later replaced from another ecosystem.
- Correct Answer: Option C
Which of the following statements is correct about biogeochemical cycling?
- A. The phosphorus cycle involves the recycling of atmospheric phosphorus.
- B. The phosphorus cycle is a cycle that involves the weathering of rocks.
- C. The carbon cycle is a localized cycle that primarily involves the burning of fossil fuels.
- D. The carbon cycle has maintained a constant atmospheric concentration of CO2 for the past million years.
- Correct Answer: Option B