Bio test 4

Why do moderate levels of disturbance result in an increase in community diversity? A) Habitats are opened up for less competitive species. B) Competitively dominant species infrequently exclude less competitive species after a moderate disturbance. C) The environmental conditions become optimal. D) The resulting uniform habitat supports stability, which in turn supports diversity. E) Less-competitive species evolve strategies to compete with dominant species.

a

Which of the following locations are major reservoirs for carbon for the carbon cycle? I) atmosphere II) sediments and sedimentary rocks III) fossilized plant and animal remains (coal, oil, and natural gas) IV) plant and animal biomass A) only I and III B) only II and IV C) only I, II, and IV D) only II, III, and IV E) I, II, III, and IV

e

Which of the following support(s) the observation that herbivores do not generally eat all of the available plants? I) top-down control hypothesis II) poor nutrition hypothesis III) plant-defense hypothesis A) only I B) only II C) only III D) only II and III E) I, II, and III

e

Why are changes in the global carbon cycle important? I) Burning reduces available carbon for primary producers and, therefore, primary consumers. II) Deforestation and suburbanization reduce an area's net primary productivity. III) Increasing atmospheric concentrations of carbon dioxide could alter Earth's climate. IV) By using fossil fuels we are destroying a nonrenewable resource. A) only I and III B) only II and IV C) only I, II, and IV D) only II, III, and IV E) only I, II, III, and IV

e

Which one of the following animals would most likely be defined as a keystone species? A) sea otter B) housefly C) fathead minnow D) nauplii (a species of zooplankton)

a

Why is energy lost when herbivores eat primary producers? A) Primary producers have energy stored in indigestible substances. B) Primary producers cannot produce once eaten. C) Digestion takes place so rapidly that very little energy is absorbed. D) Most primary producers contain no usable energy for herbivores.

a

46) Imagine five forest communities, each with one hundred individuals distributed among four different tree species (W, X, Y, and Z). Which forest community would be most diverse? A) 25W, 25X, 25Y, 25Z B) 40W, 30X, 20Y, 10Z C) 50W, 25X, 15Y, 10Z D) 70W, 10X, 10Y, 10Z E) 100W, 0X, 0Y, 0Z

a

According to bottom-up and top-down control models of community organization, which of the following expressions would imply that an increase in the size of a carnivore (C) population would negatively impact its prey (P) population, but not vice versa? A) P ← C B) P → C C) C ↔ P D) P ← C → P E) C ← P →

a

As climate changes because of global warming, plant species' ranges in the northern hemisphere may move northward. The trees that are most likely to avoid extinction in such an environment are those that _____. A) have seeds that are easily dispersed by wind or animals B) have thin seed coats C) produce well-provisioned seeds D) have seeds that become viable only after a forest fire E) disperse many seeds in close proximity to the parent tree

a

Consider the food chain of grass → grasshopper → mouse → snake → hawk. About how much of the chemical energy fixed by photosynthesis of the grass (100 percent) is available to the hawk? A) 0.01% B) 0.1% C) 1% D) 10% E) 60%

a

Which of the following human activities is impacting the water cycle the LEAST? A) increase in asphalt and concrete surfaces B) conversion of grasslands and forests into agricultural fields C) increased processing of salt water to freshwater D) increases in irrigated agriculture

c

Elephants are not the most dominant species in African grasslands, yet they influence community structure. The grasslands contain scattered woody plants, but they are kept in check by the uprooting activities of the elephants. Take away the elephants, and the grasslands convert to forests or to shrublands. The newly growing forests support fewer species than the previous grasslands. Which of the following describes why elephants are the keystone species in this scenario? A) Elephants exhibit a disproportionate influence on the structure of the community relative to their abundance. B) Grazing animals depend upon the elephants to convert forests to grassland. C) Elephants prevent drought in African grasslands. D) Elephants are the biggest herbivore in this community. E) Elephants help other populations survive by keeping out many of the large African predators.

a

How does inefficient transfer of energy among trophic levels result in the typically high endangerment status of many top-level 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) Top-level predators are more likely to be stricken with parasites.

a

If a meteor impact or volcanic eruption injected a lot of dust into the atmosphere and reduced the sunlight reaching Earth's surface by 70 percent for one year, which of the following marine communities most likely would be least affected? A) deep-sea vent B) coral reef C) intertidal D) pelagic E) estuary

a

If you are interested in observing a relatively simple community structure in a clear water lake, you would do well to choose diving into _____. A) an oligotrophic lake B) a eutrophic lake C) a relatively shallow lake D) a nutrient-rich lake E) a lake with consistently warm temperatures

a

In temperate lakes, the surface water is replenished with nutrients during turnovers that occur in the _____. A) autumn and spring B) autumn and winter C) spring and summer D) summer and winter E) summer and autumn

a

Some birds follow moving swarms of army ants in the tropics. As the ants march along the forest floor hunting insects and small vertebrates, birds follow and pick off any insects or small vertebrates that fly or jump out of the way of the ants. What is the result of the association between birds and ants? A) Birds benefit from the association but have no impact on the ants. B) Birds benefit from the association and harm the ants. C) Birds and ants benefit from the association. D) Birds do not benefit from the association, but the ants do. E) Neither birds nor ants benefit from the association.

a

The competitive exclusion principle states that _____. A) it is not possible for two species with the same niche to coexist in the same region B) it is not possible for two species to compete for the same resources C) two species with different niches will not compete for the same resources D) two species with the same niche will constantly be competing for resources

a

The specific abiotic factors defining a biome are _____. I) annual variation in temperature and precipitation II) average annual temperature and moisture levels III) maximum annual temperature and moisture levels IV) maximum annual temperatures, moisture levels, and average annual temperature A) only I and II B) only III and IV C) only I, II, and IV D) only II, III, and IV E) only I, II, and III

a

Theoretically, which would be the most effective way to disrupt a Hadley cell? A) Remove all equatorial moisture and convection. B) Extensively water the deserts. C) Heat the poles. D) Shift the Sun to apply direct rays 30 degrees south latitude.

a

What is the main difference between a disturbance and a disturbance regime? A) A disturbance regime includes defining the predictable frequency and severity of the disturbance. B) A disturbance regime includes defining the length of the disturbance. C) A disturbance regime is a more specific type of disturbance. D) They are essentially the same thing.

a

Which abiotic factor would have the most significant physiological effect on migrating salmon? A) water solute content B) competition for resources C) ambient temperature D) human-built structural interferences

a

Which of the following can be said about light in aquatic environments? A) Water selectively reflects and absorbs certain wavelengths of light. B) Photosynthetic organisms that live in deep water probably use red light. C) Longer wavelengths penetrate to greater depths. D) Light penetration seldom limits the distribution of photosynthetic species. E) Most photosynthetic organisms avoid the surface where the light is too intense.

a

Which of the following is a consequence of biological magnification (biomagnification)? A) Toxic chemicals in the environment pose greater risk to top-level predators than to primary consumers. B) Populations of top-level predators are generally smaller than populations of primary consumers. C) The biomass of producers in an ecosystem is generally higher than the biomass of primary consumers. D) Only a small portion of the energy captured by producers is transferred to consumers. E) The amount of biomass in the producer level of an ecosystem decreases if the producer turnover time increases.

a

Which of the following is responsible for the differences in summer and winter temperature stratification of deep temperate zone lakes? A) Water is densest at 4°C. B) Oxygen is most abundant in deeper waters. C) Winter ice sinks in the summer. D) Stratification is caused by a thermocline. E) Stratification always follows the fall and spring turnovers.

a

Which of the following locations is the main reservoir for nitrogen in the nitrogen cycle? A) atmosphere B) sedimentary bedrock C) fossilized plant and animal remains (coal, oil, and natural gas) D) plant and animal biomass E) soil

a

Which of the following most often controls the rate of nutrient cycling in ecosystems? A) rate of decomposition of detritus B) primary productivity C) secondary productivity D) both primary and secondary productivity

a

Which of the following statements regarding altitude and climate are true? I) Species composition on different sides of a mountain range are often different from each other. II) Rain shadows may appear on one side of a mountain range. III) The higher the altitude, the warmer the climate. IV) Both sides of a mountain range generally receive equal amounts of precipitation. A) only I and II B) only III and IV C) only I, II, and IV D) only II, III, and IV E) only I, II, and III

a

After looking at the experiment in the figure above, what can be said about nutrient export in ecosystems? Nutrient export is _____. A) typically ten times lower in a clear-cut watershed B) typically ten times higher in a clear-cut watershed C) typically ten times higher in an uncut watershed D) not affected by any form of cutting

b

Considering its total area covered, which ecosystem type represented in the figure above has a very low level of economic impact on Earth's ecosystem? A) tropical wet forest B) rock, sand, and ice C) tropical seasonal forest D) ocean neritic zone

b

Considering the global carbon cycle, which of the following is the largest reservoir of carbon? A) terrestrial ecosystems B) oceans C) atmosphere D) algae in lakes and streams

b

For most terrestrial ecosystems, pyramids composed of species abundances, biomass, and energy are similar in that 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 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

If the Earth were to reorient such that the North Pole always received direct sunlight (always faced the Sun), how would that change Earth's climate? A) The equators would not change in climate. B) The South Pole would get colder. C) The equators would get warmer. D) The North Pole would get more wind.

b

In a tide pool, fifteen species of invertebrates were reduced to eight after one species was removed. The species removed was likely a(n) _____. A) pathogen B) keystone species C) herbivore D) resource partitioner E) mutualistic organism

b

Keystone predators can maintain species diversity in a community if they _____. A) competitively exclude other predators B) prey on the community's dominant species C) allow immigration of other predators D) reduce the number of disruptions in the community E) prey only on the least abundant species in the community

b

Matter is gained or lost in ecosystems. How does this occur? A) Chemoautotrophic organisms can convert matter to energy. B) Matter can be moved from one ecosystem to another. C) Photosynthetic organisms convert solar energy to sugars. D) Detritivores convert matter to energy. E) Heterotrophs convert heat to energy.

b

Species richness increases _____. A) as we increase in altitude in equatorial mountains B) as we travel southward from the North Pole C) on islands as distance from the mainland increases D) as depth increases in aquatic communities E) as community size decreases

b

The main reason polar regions are cooler than the equator is that _____. A) there is more ice at the poles B) sunlight strikes the poles at a lower angle C) the poles are farther from the sun D) the polar atmosphere is thinner and contains fewer greenhouse gases E) the poles are permanently tilted away from the sun

b

There are more species in tropical areas than in places more distant from the equator. This is probably a result of _____. A) fewer predators B) more intense annual solar radiation C) more frequent ecological disturbances D) fewer agents of disease

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 ecosystems

b

What would happen to the seasons if the Earth were tilted 35 degrees off its orbital plane instead of the usual 23.5 degrees? A) The seasons would disappear. B) Winters and summers would be more severe. C) Winters and summers would be less severe. D) The seasons would be shorter.

b

Which habitat type in the figure above makes available the most new tissue to consumers? A) tropical wet forest B) open ocean C) algal beds and reefs D) wetlands

b

Which habitat types in the figure above cover the largest area? A) tropical wet forest plus the ocean neritic zone B) open ocean C) algal beds and reefs plus the ocean neritic zone D) wetlands plus the ocean neritic zone

b

Which marine zone would have the lowest rates of primary productivity (photosynthesis)? A) pelagic B) abyssal C) neritic D) continental shelf E) intertidal

b

Which of the following levels of ecological organization is arranged in the correct sequence from most to least inclusive A) community, ecosystem, organism, population B) ecosystem, community, population, organism C) population, ecosystem, organism, community D) organism, population, community, ecosystem E) organism, community, population, ecosystem

b

Which one of the following is a type of species interaction with impacts that depend on prey density and effectiveness of defenses to determine the short-term impact on the prey population? A) competition B) consumption C) mutualism D) commensalism

b

Which would be the best way to directly test the hypothesis that C. stellatus (a species of barnacle) is competitively excluded from the lower intertidal zone by B. balanoides (another species of barnacle)? A) Place individuals of each species in a jar and see which species survives. B) Remove all B. balanoides from the lower intertidal zone. C) Transplant B. balanoides to the upper intertidal zone. D) Clear rocks in an entire area and document recolonization events. E) Remove all C. stellatus from the upper tidal zone.

b

) Regarding soil and organic matter in humus, which of the following statements is true? A) Humus is composed of inorganic nutrients, and organic matter is composed only of organic matter. B) Soil organic matter is completely decayed. C) Completely decayed soil organic matter is called humus. D) Eventually, the nutrients in soil organic matter are converted to organic form.

c

) Which of the following statements best describes the effect of climate on biome distribution? A) Average annual temperature and precipitation are sufficient to predict which biome will be found in an area. B) Seasonal fluctuation of temperature is not a limiting factor in biome distribution if areas have the same annual temperature and precipitation means. C) The average climate and pattern of climate are important in determining biome distribution. D) Temperate forests and grasslands are different biomes because they receive a different quality and quantity of sunlight, even though they have essentially the same annual temperature and precipitation. E) Correlation of climate with biome distribution is sufficient to determine the cause of biome patterns.

c

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 trophic levels is usually less than 20 percent efficient.

e

A certain species of pine tree survives only in scattered locations at elevations above 2800 meters in the western United States. To understand why this tree grows only in these specific places, an ecologist should _____. A) conclude that lower elevations are limiting to the survival of this species B) study the anatomy and physiology of this species C) investigate the various biotic and abiotic factors that are unique to high altitude D) analyze the soils found in the vicinity of these trees, looking for unique chemicals that may support their growth E) collect data on temperature, wind, and precipitation at several of these locations for a year

c

As big as it is, the ocean is nutrient-limited. If you wanted to investigate this phenomenon, one reasonable approach would be to _____. A) follow whale migrations in order to determine where most nutrients are located 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 marine locations E) contrast nutrient uptake by autotrophs in marine locations that are different temperatures

c

Based on the intermediate disturbance hypothesis, a community's species diversity is increased by _____. A) frequent massive disturbance B) stable conditions with no disturbance C) moderate levels of disturbance D) human intervention to eliminate disturbance E) intensive disturbance by humans

c

Detritivores _____. A) recycle chemical elements directly back to primary consumers B) synthesize organic molecules that are used by primary producers C) convert organic materials from all trophic levels to inorganic compounds usable by primary producers D) secrete enzymes that convert the organic molecules of detritus into carbon dioxide and water E) may be autotrophic or heterotrophic

c

Food chains are sometimes short because _____. A) only a single species of herbivore feeds on each plant species B) local extinction of a species causes extinction of the other species in its food chain C) most of the energy in a trophic level is lost as it passes to the next higher level D) predator species tend to be less diverse and less abundant than prey species E) most producers are inedible

c

In the nitrogen cycle, the bacteria that replenish the atmosphere with nitrogen are _____. A) Rhizobium bacteria B) nitrifying bacteria C) denitrifying bacteria D) methanogenic protozoans E) nitrogen-fixing bacteria

c

People with at least one copy of the HLA-B53 gene are better able to beat back malarial infections before the infection progresses. If this is a coevolutionary arms race between Plasmodium and humans, what would the next step in this race be? A) to see humans with more than one copy of the HLA-B53 gene B) to see humans without the HLA-B53 gene C) to see Plasmodium populations that counter the HLA-B53 gene D) to see Plasmodium populations that have the HLA-B53 gene E) to see a mutation in the HLA-B53 gene that makes it more effective against malarial infections

c

Recall that Clements's view of biological communities is that of a highly predictable and interrelated structure, while Gleason's view of biological communities is that individual species operate independently. If we set up many identical sterilized ponds in the same area and allowed them to be colonized, what should we predict if we wished to test Gleason's hypothesis? A) Identical plankton communities will develop in all ponds. B) Similar plankton communities will develop in all ponds. C) Different plankton communities will develop in all ponds. D) Limited plankton communities will develop in all ponds. E) Initially the number of species in each pond will be greater than the number normally found in similar environments.

c

Some birds follow moving swarms of army ants in the tropics. As the ants march along the forest floor hunting insects and small vertebrates, birds follow and pick off any insects or small vertebrates that fly or jump out of the way of the ants. This situation is an example of what kind of species interaction between the birds and the ants? A) cooperation B) consumption C) commensalism D) parasitism E) mutualism

c

Suppose you are studying the nitrogen cycling in a pond ecosystem over the course of a month. While you are collecting data, a flock of one hundred 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 twelve-hour period, multiply this number by 100, and add that amount to the total nitrogen in the ecosystem. B) Find out how much nitrogen is eliminated by a Canada goose over about a twelve-hour period, multiply this number by 100, and subtract that amount from the total nitrogen in the ecosystem. C) Find out how much nitrogen is consumed and eliminated by a Canada goose over about a twelve-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

What is the main advantage of controlled burnings of forested areas? Controlled burnings _____. A) eliminate the possibility of forest fires B) clear forested areas for farmland C) prevent the overgrowth of the underbrush D) allow new species to form

c

Which category in the figure above makes available the highest productivity per square meter? A) tropical wet forest B) open ocean C) algal beds and reefs D) wetlands

c

Which of the following are important biotic factors that can affect the structure and organization of biological communities? A) precipitation, wind B) nutrient availability, soil pH C) predation, competition D) temperature, water E) light intensity, seasonality

c

Which of the following best substantiates why location 3 is an equatorial (tropical) climate? A) It has a monsoon season during the winter months. B) It has consistent monthly averages for rainfall. C) The temperature is high for each monthly average. D) The temperatures reach 100°F during some months. E) The temperatures are lower in June, July, and August.

c

Which of the following has the greatest effect on the rate of chemical cycling in an ecosystem? A) the ecosystem's rate of primary production B) the production efficiency of the ecosystem's consumers C) the rate of decomposition in the ecosystem D) the trophic efficiency of the ecosystem E) the location of the nutrient reservoirs in the ecosystem

c

Which of the following statements is consistent with the principle of competitive exclusion? A) Bird species generally do not compete for nesting sites. B) The random distribution of one competing species will have a positive impact on the population growth of the other competing species. C) Two species with the same fundamental niche will exclude other competing species. D) Even a slight reproductive advantage will eventually lead to the elimination of the less well adapted of two competing species. E) Natural selection tends to increase competition between related species.

c

While traveling in Texas, you stumble across a snake with red, yellow, and black bands. You somehow remember that this could be a poisonous coral snake or a harmless milk snake, but you forget how to differentiate them because they both have similar colors and banding patterns. You wisely decide not to pick up the snake. What defense of the snake was successful in preventing you from grabbing the snake? A) constitutive defense B) Müllerian mimicry C) Batesian mimicry D) inducible defenses

c

Why are food chains relatively short? A) Top-level feeders tend to be more numerous than lower-trophic-level species. B) Top-level feeders tend to be small but are capable of conserving more energy. C) Longer chains are less stable and energy transfer between trophic levels is inefficient. D) There are only so many organisms that are adapted to feed on other types of organisms. E) Food chain length is ultimately determined by the photosynthetic efficiency of producers.

c

You own three hundred acres of patchy temperate forest. Which one of the following actions would increase the net primary productivity of the area the most? A) adding fertilizer to the entire area B) introducing one hundred rabbits into the area C) planting five hundred new trees D) relocating all of the deer found in the area

c

Approximately how many kilograms (kg) of carnivore (secondary consumer) biomass can be supported by a field plot containing 1000 kg of plant material? A) 10,000 B) 1000 C) 100 D) 10 E) 1

d

Based on the experiment in the figure above, which of the following are plausible reasons for the result? I) No nutrients evaporate now that vegetation is absent. II) Nutrients dissolve in the water running through the watershed. III) Nutrients are attached to small particles of sand or clay that leave the watershed. IV) Plant roots that held soil particles in place are no longer there. A) only I and III B) only II and IV C) only I, II, and IV D) only II, III, and IV E) only I, II, and III

d

Imagine that a deep temperate zone lake did not turn over during the spring and fall seasons. Based on the physical and biological properties of limnetic ecosystems, what would be the difference from normal seasonal turnover? A) The lake would be uniformly cold during the winter and summer. B) The lake would fail to freeze over in winter. C) An algal bloom of algae would result every spring. D) Lakes would suffer a nutrient depletion in surface layers. E) The pH of the lake would become increasingly alkaline.

d

In a particular case of secondary succession, three species of wild grass all invaded a field. By the second season, a single species dominated the field. A possible factor in this secondary succession was _____. A) equilibrium B) facilitation C) immigration D) inhibition E) parasitism

d

In biology, an arms race occurs when _____. A) predators become dominant over their prey species leading to the local extinction of the prey B) a new species evolves into two separate species C) a new niche is created because of interactions between species D) there is a repeating cycle of reciprocal adaptation E) a prey species adapts and is able to coexist with its predators

d

In the hypothesis that C. stellatus (a species of barnacle) is competitively excluded from the lower intertidal zone by B. balanoides (another species of barnacle), what could be concluded about the two species? A) The fundamental and realized niches of B. balanoides and C. stellatus are identical. B) The fundamental and realized niches of B. balanoides and C. stellatus are different. C) The fundamental and realized niches of B. balanoides are different, but the fundamental and realized niches of C. stellatus are identical. D) The fundamental and realized niches of B. balanoides are identical, but the fundamental and realized niches of C. stellatus are different.

d

Turnover of water in temperate lakes during the spring and fall is made possible by which of the following? A) warm, less dense water layered at the top B) cold, more dense water layered at the bottom C) a distinct thermocline between less dense, warm water and cold, dense water D) the changes in the density of water as seasonal temperatures change E) currents generated by nektonic animals

d

What do researchers typically focus on when they study a particular biogeochemical cycle? I) the nature and size of the reservoirs II) the rate of element movement between reservoirs III) interaction of the current cycle with other cycles A) only I B) only II C) only III D) only II and III E) I, II, and III

d

What is the main reason for using food webs instead of food chains in analyzing ecosystems? I) Most organisms eat more than one type of food. II) Most organisms feed at several trophic levels. III) The decomposition cycle needs to be shown. A) only I B) only II C) only III D) only I and II E) I, II, and III

d

When primary producers expend energy to build new tissue, this is _____. A) net primary productivity B) the amount of energy available to consumers C) maintenance costs D) net primary productivity and the amount of energy available to consumers E) maintenance costs and the amount of energy available to consumers

d

Which is a likely biotic factor limiting songbird distribution in Hawaii to alpine habitats? A) temperature B) oxygen content C) moisture D) insects causing fatal diseases in songbirds at lower altitudes

d

Which level of ecological study focuses the most on abiotic factors? A) speciation ecology B) population ecology C) community ecology D) ecosystem ecology

d

Which of the following is a correct statement about the MacArthur/Wilson Island Biogeography Model? A) The more species that inhabit an island, the lower the extinction rate. B) As the number of species on an island increases, the emigration rate decreases. C) Competitive exclusion is less likely on an island that has large numbers of species. D) Small islands receive few new immigrant species. E) Islands closer to the mainland have higher extinction rates.

d

Which of the following is a widely supported explanation for the tendency of tropical communities to have greater species diversity than temperate or polar communities? A) They are less likely to be affected by human disturbance. B) There are fewer parasites to negatively affect the health of tropical communities. C) Tropical communities are low in altitude, whereas temperate and polar communities are high in altitude. D) Tropical communities are generally older than temperate and polar communities. E) More competitive dominant species have evolved in temperate and polar communities.

d

Which of the following is an example of a commensalism? A) fungi residing in plant roots, such as endomycorrhizae B) bacteria fixing nitrogen in plants C) rancher ants that protect aphids in exchange for sugar-rich honeydew D) cattle egrets eating insects stirred up by grazing bison

d

Which of the following terms is used by ecologists to describe the community interaction where one organism makes the environment more suitable for another organism? A) parasitism B) mutualism C) inhibition D) facilitation E) commensalism

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 the reactions of cellular respiration. C) Heat produced by cellular respiration is used by heterotrophs for thermoregulation. D) It is eliminated as feces or is dissipated into space as heat, consistent with the second law of thermodynamics. E) It is recycled by decomposers to smaller and smaller forms until it finally breaks down to form soil.

d

Why is terrestrial productivity higher in equatorial climates? A) Productivity increases with temperature. B) Productivity increases with water availability. C) Productivity increases with available sunlight. D) The answer is most likely a combination of the other responses.

d

) Which of the following would be most significant in understanding the structure of an ecological community? I) determining how many species are present overall II) determining which particular species are present III) determining the kinds of interactions that occur among organisms of different species IV) determining the relative abundance of species A) only I and III B) only II and IV C) only I, II, and III D) only II, III, and IV E) I, II, III, and IV

e

As you study two closely related predatory insect species, the two-spot and the three-spot avenger beetles, you notice that each species seeks prey at dawn in areas without the other species. However, where their ranges overlap, the two-spot avenger beetle hunts at night and the three-spot hunts in the morning. When you bring them into the laboratory and isolate the two different species, you discover that the offspring of both species are found to be nocturnal. You have discovered an example of _____. A) mutualism B) character displacement C) Batesian mimicry D) facultative commensalism E) resource partitioning

e

Considering the global carbon cycle, where are humans having a great impact? I) terrestrial ecosystems II) oceans III) atmosphere A) only I B) only II C) only III D) only I and III E) I, II, and III

e

Detritus can be consumed by which of the following primary decomposers? I) bacteria II) archaea III) fungi IV) earthworms A) only I and III B) only II and IV C) only I, II, and IV D) only II, III, and IV E) only I, II, III, and IV

e

During a year, plants never use 100% of the incoming solar radiation for photosynthesis. What is a reasonable explanation for this? I) Plants cannot photosynthesize as well during winter (in cold winter climates). II) Plants cannot photosynthesize as well on cloudy days. III) The pigments that drive photosynthesis respond to only a fraction of the wavelengths that are available. A) only I B) only II C) only III D) only II and III E) I, II, and III

e

For a species to be called "invasive," it must _____. I) be introduced to a new area II) spread rapidly in this new area III) eliminate native species A) only I B) only II C) only III D) only II and III E) I, II, and III

e

If the flow of energy in an arctic ecosystem goes through a simple food chain, perhaps involving humans, starting from phytoplankton to zooplankton 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 fish is lower than that of the seals. C) Seal meat probably contains the lowest concentrations of fat-soluble toxins. D) Seal populations are larger than fish populations. E) Fish can potentially provide more food for humans than seal meat.

e

If two species are close competitors, and one species is experimentally removed from the community, the remaining species would be expected to _____. A) eventually become competitively superior to the other species B) change its fundamental niche C) decline in abundance D) become the target of specialized parasites E) expand its realized niche

e

Nitrogen is available to plants mostly in the form of _____. A) nitrogen in the atmosphere B) nitrite ions in the soil C) uric acid from animal excretions D) nucleic acids from decomposing plants and animals E) nitrate and ammonium ions in the soil

e

Once heat is transferred to the soil, where does it go next (reference the study by Noormets et al. 2004)? I) The heat is emitted back to the atmosphere. II) The heat is transferred to other soil layers. III) The heat is stored in the soil. A) only I B) only II C) only III D) only II and III E) I, II, and III

e

The feeding relationships among the species in a community determine the community's _____. A) secondary succession B) ecological niche C) species richness D) species-area curve E) trophic structure

e

Which of the following biomes has the highest variation in annual temperature? A) subtropical deserts B) arctic tundra C) temperate forests D) temperate grasslands E) boreal forests / taiga

e

Which of the following is a source of human-fixed nitrogen? I) industrially produced fertilizers II) cultivation of soybeans III) irrigation agriculture A) only I B) only II C) only III D) only II and III E) only I and II

e