Chapter 55 Review Questions
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. E) deprivation of nitrogen to ecosystems adjacent to nitrogen application.
A
If this were a marine food web, the smallest organism might be A) A. B) F. C) C. D) I. E) E.
A
In general, the total biomass in a terrestrial ecosystem will be greatest for which trophic level? A) producers B) herbivores C) primary consumers D) tertiary consumers E) secondary consumers
A
What is the most important role of photosynthetic organisms in an ecosystem? A) converting inorganic compounds into organic compounds B) absorbing solar radiation C) producing organic detritus for decomposers D) dissipating heat E) recycling energy from other tropic levels
A
Which of the following has the smallest biomass? A) hawk B) snake C) shrew D) grasshopper E) grass
A
Which of the following lists of organisms is ranked in correct order from lowest to highest percent in production efficiency? A) mammals, fish, insects B) insects, fish, mammals C) fish, insects, mammals D) insects, mammals, fish E) mammals, insects, fish
A
Which of the following probably contains the highest concentration of toxic pollutants (biological magnification)? A) hawk B) snake C) shrew D) grasshopper E) grass
A
Which of the following terms encompasses all of the others? A) heterotrophs B) herbivores C) carnivores D) primary consumers E) secondary consumers
A
Which species is autotrophic?
A
A secondary consumer, such as a fox, receives what percent of the energy fixed by primary producers in a typical field ecosystem? A) 0.1% B) 1% C) 10% D) 20% E) 90%
B
Agricultural lands frequently require nutritional supplementation because A) nitrogen-fixing bacteria and detrivores do not cycle nutrients as effectively as they do on wild lands. B) the nutrients that enter the plants are not returned to the soil on lands where they are harvested. C) the prairies that comprise good agricultural land tend to be nutrient-poor. D) grains raised for feed must be fortified, and thus require additional nutrients. E) cultivation of agricultural lands inhibits the decomposition of organic matter.
B
Ecosystems are A) processors of energy and transformers of matter. B) processors of matter and transformers of energy. C) processors of matter and energy. D) transformers of matter but not of energy. E) neither transformers or processors of matter nor energy.
B
For most terrestrial ecosystems, pyramids of numbers, biomass, and energy are essentially the same-they have a broad base and a narrow top. The primary reason for this pattern is that A) secondary consumers and top carnivores require less energy than producers. B) at each step, energy is lost from the system as a result of keeping the organisms alive. C) as matter passes through ecosystems, some of it is lost to the environment. D) biomagnification of toxic materials limits the secondary consumers and top carnivores. E) top carnivores and secondary consumers have a more general diet than primary producers.
B
Species C is toxic to predators. Which species is most likely to benefit from being a mimic of C?
B
The total biomass of photosynthetic autotrophs present in an ecosystem is known as A) gross primary productivity. B) standing crop. C) net primary productivity. D) secondary productivity. E) trophic efficiency.
B
To recycle nutrients, the minimum an ecosystem must have is A) producers. B) producers and decomposers. C) producers, primary consumers, and decomposers. D) producers, primary consumers, secondary consumers, and decomposers. E) producers, primary consumers, secondary consumers, top carnivores, and decomposers.
B
Trophic efficiency is A) the ratio of net secondary production to assimilation of primary production. B) the percentage of production transferred from one trophic level to the next. C) a measure of how nutrients are cycled from one trophic level to the next. D) usually greater than production efficiencies. E) about 90% in most cosystems
B
What would be a likely entry for box B? A) decomposer population carries on cellular respiration and uses up oxygen B) plants no longer producing oxygen C) warm water holding less oxygen than cold water D) fish that cannot acclimate to low oxygen levels E) carbon dioxide building up from cellular respiration by decomposers
B
Which of the following ecosystems would likely have a larger net primary productivity/hectare? A) open ocean because of the total biomass of photosynthetic autotrophs B) grassland because of the small standing crop biomass that results from consumption by herbivores and rapid decomposition C) tropical rainforest because of the massive standing crop biomass and species diversity. D) cave due to the lack of photosynthetic autotrophs E) tundra because of the incredibly rapid period of growth during the summer season.
B
Which of the following is a tertiary consumer? A) hawk B) snake C) shrew D) grasshopper E) grass
B
Which of the following statements best describes why biologists are currently concerned with global warming and the thawing of permafrost in many areas of the tundra biome? A) The thawing process will likely decrease the abundance and diversity of soil-dwelling organisms in tundra habitats. B) The bacterial decomposition of the thawed organic materials on the widespread areas of the tundra will produce large quantities of CO2, which will add to greenhouse gases and exacerbate global warming. C) Oil and coal deposits will thaw and rise to the surface (because of their lower density) of the tundra, destroying millions of acres of arctic habitat. D) Populations of humans inhabiting the arctic will have to move to more southern latitudes, resulting in increased competition for resources in already densely populated areas. E) Migratory species of waterfowl will likely be less successful finding food in thawed tundra, and population numbers will drop dramatically.
B
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. E) The nitrogen cycle involves movement of diatomic nitrogen between the biotic and abiotic components of the ecosystem.
B
A porcupine eats 3,000 J of plant material. 1,600 J is indigestible and is eliminated as feces. 1,300 J are used in cellular respiration. What is the approximate production efficiency of this animal? A) .03% B) 1% C) 3% D) 10% E) 30%
C
As big as it is, the ocean is nutrient-limited. If you wanted to investigate this, one reasonable avenue would be to A) follow whale migrations in order to determine where most nutrients are. B) observe Antarctic Ocean productivity from year to year to see if it changes. C) experimentally enrich some areas of the ocean and compare their productivity to that of untreated areas. D) compare nutrient concentrations between the photic zone and the benthic zone in various locations E) contrast nutrient uptake by autotrophs in oceans of different temperatures.
C
How does phosphorus normally enter ecosystems? A) cellular respiration B) photosynthesis C) rock weathering D) geological uplifting (subduction and vulcanism) E) atmospheric phosphorous dust
C
How is it that the open ocean produces the highest net primary productivity of Earth's ecosystems, yet net primary productivity per square meter is relatively low? A) Oceans contain greater concentrations of nutrients compared to other ecosystems. B) Oceans receive a greater amount of solar energy per unit area. C) Oceans have the greatest total area. D) Oceans possess greater species diversity. E) Oceanic producers are generally much smaller than its consumers.
C
If the Sun were to suddenly stop providing energy to Earth, most ecosystems would vanish. Which of the following ecosystems would likely survive the longest after this hypothetical disaster? A) tropical rainforest B) tundra C) benthic ocean D) grassland E) desert
C
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. E) A, B, C, and D are all correct.
C
In the nitrogen cycle, the bacteria that replenish the atmosphere with N2 are A) Rhizobium bacteria. B) nitrifying bacteria. C) denitrifying bacteria. D) methanogenic protozoans. E) nitrogen-fixing bacteria.
C
Many homeowners mow their lawns during the summer and collect the clippings, which are then hauled to the local landfill. Which of the following actions would most benefit the local ecosystem? A) Allow sheep to graze the lawn and then collect the sheep's feces to be delivered to the landfill. B) Collect the lawn clippings and burn them. C) Either collect the clippings and add them to a compost pile, or don't collect the clippings and let them decompose into the lawn. D) Collect the clippings and wash them into the nearest storm sewer that feeds into the local lake. E) Dig up the lawn and cover the yard with asphalt.
C
Subtraction of which of the following will convert gross primary productivity into net primary productivity? A) the energy contained in the standing crop B) the energy used by heterotrophs in respiration C) the energy used by autotrophs in respiration D) the energy fixed by photosynthesis E) all solar energy
C
Suppose you are studying the nitrogen cycling in a pond ecosystem over the course of a year. While you are collecting data, a flock of 100 Canada geese lands and spends the night during a fall migration. What could you do to eliminate error in your study as a result of this event? A) Find out how much nitrogen is consumed in plant material by a Canada goose over about a 12-hour period and multiply this number by 100 and add to the total nitrogen in the ecosystem. B) Find out how much nitrogen is eliminated by a Canada goose over about a 12-hour period and multiply this number by 100 and subtract from the total nitrogen in the ecosystem. C) Find out how much nitrogen is consumed and eliminated by a Canada goose over about a 12-hour period and multiply this number by 100; enter this +/-value into the nitrogen budget of the ecosystem. D) Do nothing. The Canada geese visitation to the lake would have negligible impact on the nitrogen budget of the pond. E) Put a net over the pond so that no more migrating flocks can land on the pond and alter the nitrogen balance of the pond.
C
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. E) chemical cycling through an ecosystem.
C
Which of the following causes excessively high levels of toxic chemicals in fish-eating birds? A) depletion of atmospheric ozone B) turnover C) biological magnification D) greenhouse effect E) eutrophication
C
Which of the following is true of detrivores? A) They recycle chemical elements directly back to primary consumers. B) They synthesize organic molecules that are used by primary producers. C) They convert organic materials from all trophic levels to inorganic compounds usable by primary producers. D) They secrete enzymes that convert the organic molecules of detritus into CO2 and H2O. E) Some species are autotrophic, while others are heterotrophic.
C
Which of the following statements is true? A) An ecosystem's trophic structure determines the rate at which energy cycles within the system. B) At any point in time, it is impossible for consumers to outnumber producers in an ecosystem. C) Chemoautotrophic prokaryotes near deep-sea vents are primary producers. D) There has been a well-documented increase in atmospheric nitrogen over the past several decades. E) The reservoir of ecosystem phosphorous is the atmosphere.
C
Why are ecologists concerned about the shift in date from May 28 in 1980 to May 15 in 2000 of the caterpillar peak mass? A) The caterpillars will eat much of the foliage of the trees where flycatchers nest, and their nests will be more open to predation. B) The earlier hatching of caterpillars will compete with other insect larval forms on which the flycatchers also feed their young. C) The flycatcher nestlings in 2000 will miss the peak mass of caterpillars and may not be as well fed. D) The flycatchers will have to migrate sooner to match their brood-rearing season with the time of caterpillar peak mass. E) Pesticides, which have a negative effect on the ecosystem, will have to be used to control the earlier outbreak of caterpillar hatching.
C
Aquatic ecosystems that are most readily damaged by acid are those that lack an important buffer that dissolves into the runoff after a precipitation event. What is this buffer? A) calcium B) carbonic acid C) nitrate D) bicarbonate E) sulfate
D
How is it that satellites can detect differences in primary productivity on Earth? A) Photosynthesizers absorb more visible light in the 350—750 wavelengths. B) Satellite instruments can detect reflectance patterns of the photosynthesizers of different ecosystems. C) Sensitive satellite instruments can measure the amount of NADPH produced in the summative light reactions of different ecosystems. D) By comparing the wavelengths of light captured and reflected by photosynthesizers to the amount of light reaching different ecosystems. E) By measuring the amount of water vapor emitted by transpiring photosynthesizers.
D
If this were a terrestrial food web, the combined biomass of C + D would probably be A) greater than the biomass of A. B) less than the biomass of H. C) greater than the biomass of B. D) less than the biomass of A + B. E) less than the biomass of E.
D
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. E) All of the permafrost ice would become runoff, and this volume of water will cause sea levels to rise globally, flooding some of the most important photosynthetic CO2 sink regions on the planet.
D
The difference between net and gross primary productivity would likely be greatest for A) phytoplankton in the ocean. B) corn plants in a farmer's field. C) prairie grasses. D) an oak tree in a forest. E) sphagnum moss in a bog.
D
The most likely cause for the shift in caterpillar peak mass is A) pesticide use. B) earlier migration returns of flycatchers. C) an innate change of biological clock by caterpillars. D) global warming. E) a decrease in the amount of calcium in the ecosystem.
D
What would be a likely entry for box A? A) increased temperature B) elimination of zooplankton C) increased sunlight D) fertilizers washed into the lake E) increased ultraviolet radiation
D
When levels of CO2 are experimentally increased, C3 plants generally respond with a greater increase in productivity than C4 plants. This is because A) C3 plants are more efficient in their use of CO2. B) C3 plants are able to obtain the same amount of CO2 by keeping their stomata open for shorter periods of time. C) C4 plants don't use CO2 as their source of carbon. D) C3 plants are more limited than C4 plants by CO2 availability because of transpirational water loss. E) C3 plants have special adaptations for CO2 uptake, such as larger stomata.
D
Which of the following are responsible for the conversion of most organic material into CO2, which can be utilized in primary production? A) autotrophs B) detrivores C) primary consumers D) herbivores E) carnivores
D
Which of the following describes carbon dioxide, methane, and water vapor re-reflecting infrared radiation back toward Earth? A) depletion of atmospheric ozone B) turnover C) biological magnification D) greenhouse effect E) eutrophication
D
Which of the following properly links the nutrient to its reservoir? A) Nitrogenionic nitrogen in the soil B) Wateratmospheric water vapor C) Carbondissolved CO2 in aquatic ecosystems D) Phosphoroussedimentary rocks E) A, B, C, and D are all correct
D
Which of these ecosystems accounts for the largest amount of Earth's net primary productivity? A) tundra B) savanna C) salt marsh D) open ocean E) tropical rain forest
D
Which of these ecosystems has the highest net primary productivity per square meter? A) savanna B) open ocean C) boreal forest D) tropical rain forest E) temperate forest
D
Which statement best describes what ultimately happens to the chemical energy that is not converted to new biomass in the process of energy transfer between trophic levels in an ecosystem? A) It is undigested and winds up in the feces and is not passed on to higher trophic levels. B) It is used by organisms to maintain their life processes through cellular respiration reactions. C) Heat produced by cellular respiration is used by heterotrophs to thermoregulate. D) It is dissipated into space as heat in accordance with the second law of thermodynamics. E) It is recycled by decomposers to a form that is once again usable by primary producers.
D
Burning fossil fuels releases oxides of sulfur and nitrogen. Ultimately, these are probably responsible for A) the death of fish in Norwegian lakes. B) rain with a pH as low as 3.0. C) calcium deficiency in soils. D) direct damage to plants by leaching nutrients from the leaves. E) A, B, C, and D are all correct.
E
If the flow of energy in an arctic ecosystem goes through a simple food chain, perhaps involving humans, starts from seaweeds to fish to seals to polar bears, then which of the following could be true? A) Polar bears can provide more food for humans than seals can. B) The total biomass of the seaweeds is lower than that of the seals. C) Seal meat probably contains the highest concentrations of fat-soluble toxins. D) Seal populations are larger than fish populations. E) The seaweed can potentially provide more food for humans than the seal meat can.
E
If you wanted to convert excess grain into the greatest amount of animal biomass, to which animal would you feed the grain? A) chickens B) mice C) cattle D) carp (a type of fish) E) mealworms (larval insects)
E
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) Trees are generally smaller in temperate forests, so fewer nutrients will be removed from the temperate forest ecosystem during a harvest. B) 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) 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) 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. E) Typical harvests remove up to 75% of the nutrients in the woody trunks of tropical rain forest trees, leaving nutrient-impoverished soils behind.
E
Nitrogen is available to plants only in the form of A) N2 in the atmosphere. B) nitrite ions in the soil. C) uric acid from animal excretions. D) amino acids from decomposing plant and animal proteins. E) nitrate ions in the soil.
E
Of the following pairs, which are the main decomposers in a terrestrial ecosystem? A) fungi and prokaryotes B) plants and mosses C) insects and mollusks D) mammals and birds E) annelids and nematodes
E
The amount of chemical energy in consumers' food that is converted to their own new biomass during a given time period is known as which of the following? A) biomass B) standing crop C) biomagnification D) primary production E) secondary production
E
The producers in aquatic ecosystems include organisms in which of the following groups? A) cyanobacteria B) algae C) plants D) photoautotrophs E) A, B, C, and D are all correct
E
Which of the following is caused by excessive nutrient runoff into lakes? A) depletion of atmospheric ozone B) turnover C) biological magnification D) greenhouse effect E) eutrophication
E
Which of the following is primarily responsible for limiting the number of trophic levels in most ecosystems? A) Many primary and higher-order consumers are opportunistic feeders. B) Decomposers compete with higher-order consumers for nutrients and energy. C) Nutrient cycles involve both abiotic and biotic components of ecosystems. D) Nutrient cycling rates tend to be limited by decomposition. E) Energy transfer between tropic levels is in almost all cases less than 20% efficient.
E
Which species is most likely the decomposer?
E
You have a friend who is wary of environmentalists' claims that global warming could lead to major biological change on Earth. Which of the following statements can you truthfully make in response to your friend's suspicions? A) We know that atmospheric carbon dioxide has increased in the last 150 years. B) Through measurements and observations, we know that carbon dioxide levels and temperature fluctuations were directly correlated even in prehistoric times. C) Global warming could have significant effects on United States agriculture. D) Sea levels will likely rise, displacing as much as 50% of the world's human population. E) A, B, C, and D are all correct
E
A cow's herbivorous diet indicates that it is a(n) A) primary consumer. B) secondary consumer. C) decomposer. D) autotroph. E) producer.
A
Aquatic primary productivity is most limited by which of the following? A) light and nutrient availability B) predation by fishes C) increased pressure with depth D) disease E) temperature
A
How are matter and energy used in ecosystems? A) Matter is cycled through ecosystems; energy is not. B) Energy is cycled through ecosystems; matter is not. C) Energy can be converted into matter; matter cannot be converted into energy. D) Matter can be converted into energy; energy cannot be converted into matter. E) Matter is used in ecosystems; energy is not
A
How does inefficient transfer of energy among trophic levels result in the typically high endangerment status of many top predators? A) Top-level predators are destined to have small populations that are sparsely distributed. B) Predators have relatively large population sizes. C) Predators are more disease-prone than animals at lower trophic levels. D) Predators have short life spans and short reproductive periods. E) A, B C, and D are all correct.
A
Which of the following causes an increase in the intensity of UV radiation reaching the Earth? A) depletion of atmospheric ozone B) turnover C) biological magnification D) greenhouse effect E) eutrophication
A
Aquatic ecosystems are least likely to be limited by which of the following nutrients? A) nitrogen B) carbon C) phosphorus D) iron E) zinc
B
Which species is most likely an omnivore?
C
A toxic pollutant would probably reach its highest concentration in which species?
D
