Chapter 23 Global Ecology
1. Concentrations of ozone in earth’s atmosphere are highest in the
a) troposphere.
b) stratosphere.
c) mesosphere.
d) thermosphere.
e) ozonosphere.
Answer: B
2. Which of the following gases contribute to warming of the Earth’s surface through the
greenhouse effect?
a) carbon dioxide
b) methane
c) water vapor
d) nitrous oxide
e) all of the above
Answer: E
3. Before life evolved on Earth, the atmosphere
a) had much higher concentrations of oxygen.
b) had much lower concentrations of oxygen.
c) was more or less the same as it is now.
d) had much lower concentrations of carbon dioxide.
e) had much lower concentrations of hydrogen.
Answer: B
4. El Niño events
a) occur when the Southern Oscillation index is high.
b) occur when barometric pressure is lower in the western Pacific than in the eastern
Pacific.
c) include the appearance of warm currents on the Pacific coast of South America.
d) are always accompanied by La Niña events at the same time.
e) are accompanied by westward movement of the location of storm generation in the
Pacific.
Answer: C
5. Episodes of lower sea surface temperatures and higher barometric pressure in the
eastern tropical Pacific are known as La Niña events.
Answer: T
6. During El Niño events,
a) Australia experiences drought.
b) western North America experiences drought.
c) Canada and Alaska are cooler than average.
d) populations of anchovies and seabirds increase along the South American coast.
e) primary production increases around the Galápagos Islands.
Answer: A
7. Fur seals and sea lions in the Galápagos Islands experience population declines during
El Niño events because
a) their hibernation cues are disrupted by the unusual climate.
b) they are not capable of effective thermoregulation in the cooler waters around the
islands.
c) the fish they feed upon move further offshore in search of warmer water.
d) the fish they feed upon move offshore and deeper in search of cooler water.
e) the fish they feed on are driven to local extinction.
Answer: D
8. During El Niño events, primary production by phytoplankton increases sharply in the
Great Salt Lake of Utah. This is because
a) water temperatures increase.
b) nutrient concentrations are increased as lake volume shrinks.
c) decreasing salinity allows invasion of predators that control brine shrimp populations.
d) decreasing salinity allows invasion of more phytoplankton species.
e) decreasing salinity increases the efficiency of photosynthesis.
Answer: C
9. Periodic increases and decreases in red kangaroo populations in Australia are
associated with
a) predator-driven population cycles.
b) disease-driven population cycles.
c) sunspot cycles.
d) the El Niño – Southern Oscillation.
e) none of the above
Answer: D
10. Nitrogen fixation due to human activities now exceeds total global fixation by all
other biotic and abiotic agents.
Answer: T
11. Which of the following make important contributions to nitrogen fixation by human
activities?
a) combustion of fossil fuels
b) industrial production of nitrogen fertilizers
c) use of crop rotation in agriculture
d) all of the above
e) only (b) and (c)
Answer: D
12. The nation containing the largest fraction of the world’s tropical rain forest is
a) Congo.
b) Brazil.
c) Mexico.
d) The United States.
e) Indonesia.
Answer: B
13. Which of the following statements does NOT apply to tropical forest edges?
a) Edge habitat is hotter than the forest interior.
b) Edge habitat is drier than the forest interior.
c) Edge habitat has higher solar radiation than the forest interior.
d) Trees grow more rapidly and survive better in edge habitat than in the forest interior.
e) Forest fragmentation increases the ratio of edge habitat to forest interior.
Answer: D
14. A carbon dioxide concentration record from the Vostok ice core indicates
a) little change in atmospheric CO2 concentration before the Industrial Revolution.
b) dramatic increases in atmospheric CO2 associated with ice ages.
c) dramatic increases in atmospheric CO2 associated with interglacials.
d) dramatic changes in atmospheric CO2, but no obvious association with the
glacial/interglacial cycle.
e) an inverse correlation between atmospheric CO2 concentration and temperature
Answer: C
15. Atmospheric CO2 concentrations began their most recent steep increase about
a) 5000 B.C.
b) 1000 B.C.
c) 1400 A.D.
d) 1800 A.D.
e) 1950 A.D.
Answer: D
16. Human release of CO2 into the atmosphere accelerated during World War I and
World War II.
Answer: F
17. The reduction in atmospheric 14C/12C ratio associated with fossil fuel combustion is
known as the ____________.
Answer: Suess effect
18. Ozone plays an important role in shaping the environment for life on Earth because it
a) absorbs ultraviolet radiation.
b) emits ultraviolet radiation.
c) absorbs visible radiation.
d) reflects visible radiation.
e) dissolves more readily than oxygen gas in seawater.
Answer: A
19. Ozone in the stratosphere is destroyed during breakdown of ________ molecules.
Answer: chlorofluorocarbons (CFCs)
20. The 1987 Montreal Protocol was an agreement to limit human production of
a) carbon dioxide.
b) nitrate.
c) PCBs.
d) lead paint.
e) chlorofluorocarbons.
Answer: E
21. In the “U.S. LTER Network”, LTER stands for ________.
Answer: Long Term Ecological Research