You are working for the Environmental Protection Agency and researching the effect of a potentially toxic chemical in drinking water. There is no documented scientific evidence showing that the chemical is toxic, but many suspect it to be a health hazard. Using the precautionary principle, what would be a reasonable environmental policy? A) Establish no regulations until there are conclusive scientific studies. B) Set the acceptable levels of the chemical conservatively low, and keep them there unless future studies show that they can be safely raised. C) Set the acceptable levels at the highest levels encountered, and keep them there unless future studies demonstrate negative health effects. D) Caution individuals to use their own judgment in deciding whether to drink water from a potentially contaminated area. E) Establish a contingency fund to handle insurance claims in the event that the chemical turns out to produce negative health effects.

b

Which of the following statements best describes the difference in approach to studying the environment by early naturalists compared to present-day ecologists? A) Early naturalists employed a descriptive approach; present-day ecologists generate hypotheses, design experiments, and draw conclusions from their observations. B) Early naturalists manipulated the environment and observed changes in plant and animal populations, while modern ecology focuses on population dynamics. C) Early naturalists systematically recorded what they observed in their environment; modern ecology is only concerned with manʹs impact on the environment. D) Early naturalists were interested with manʹs interaction with the natural world; present-day ecologists seek to link ecology to developmental biology. E) Early naturalists were interested in interactions between organisms and their environment; present day ecologists are interested in interactions between organisms

a

Which statement best contrasts environmentalism with ecology? A) Ecology is the study of the environment; environmentalism is the study of ecology. B) Ecology provides scientific understanding of living things and their environment; environmentalism is more about conservation and preservation of life on Earth. C) Environmentalists are only involved in politics and advocating for protecting nature; ecologists are only involved in scientific investigations of the environment. D) Ecologists study organisms in environments that have been undisturbed by human activities; environmentalists study the effects of human activities on organisms. E) Environmentalism is devoted to applied ecological science; ecology is concerned with basic/theoretical ecological science

b

Of the following examples of ecological effect leading to an evolutionary effect (→), which is most correct? A) When seeds are not plentiful → trees produce more seeds. B) A few organisms of a larger population survive a drought → these survivors then emigrate to less arid environments. C) A few individuals with denser fur survive the coldest days of an ice age → the reproducing survivors all have long fur. D) Fish that swim the fastest in running water → catch the most prey and more easily escape predation. E) The insects that spend the most time exposed to sunlight → have the most mutations.

c

Rachel Carson would most likely have endorsed which of the following statements? A) Conserving wildness will lead to the preservation of the Earth. B) The greatest liberty humans have taken is with nature. C) Humans have dominion over the Earth and all of its inhabitants. D) All pesticides are unsafe and must be banned. E) The environment can repair damage created by human activity.

b

Landscape ecology is best described as the study of A) the flow of energy and materials between the biotic and abiotic components of an ecosystem. B) how the structure and function of species enable them to meet the challenges of their environment. C) what factors affect the structure and size of a population over time. D) the interactions between the different species that inhabit and ecosystem. E) the factors controlling the exchanges of energy, materials, and organisms among ecosystem patches.

e

Studying species transplants is a way that ecologists A) determine the abundance of a species in a specified area. B) determine the distribution of a species in a specified area. C) develop mathematical models for distribution and abundance of organisms. D) determine if dispersal is a key factor in limiting distribution of organisms. E) consolidate a landscape region into a single ecosystem

d

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 abiotic factors has the greatest influence on the metabolic rates of plants and animals? A) water B) wind C) temperature D) rocks and soil E) disturbances

c

Which of the following statements about light in aquatic environments is correct? 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 not too intense.

a

In mountainous areas of western North America, north-facing slopes would be expected to A) receive more sunlight than similar southern exposures B) be warmer and drier than comparable southern exposed slopes C) consistently steeper than southern exposures D) support biological communities similar to those found lower elevations on similar south-facing slopes. E) support biological communities similar to those found at higher elevations on similar south-facing slopes.

e

Coral reefs can be found on the southern east coast of the United States but not at similar latitudes on the southern west coast. Differences in which of the following most likely account for this? A) sunlight intensity B) precipitation C) day length D) ocean currents E) salinity

d

Deserts typically occur in a band at 30 degrees north and south latitude because A) descending air masses tend to be cool and dry. B) trade winds have a little moisture. C) water is heavier than air and is not carried far over land. D) ascending air tends to be moist. E) these locations get the most intense solar radiation of any location on Earth

a

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 density of water changes as seasonal temperatures change. E) currents generated by nektonic animals

d

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

Which of the following is responsible for the summer and winter stratification of deep temperate 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

Generally speaking, deserts are located in places where air masses are usually A) tropical. B) humid. C) rising. D) descending. E) expanding

d

Which of the following causes Earthʹs seasons? A) global air circulation B) global wind patterns C) ocean currents D) changes in Earthʹs distance from the sun E) the tilt of Earthʹs axis

e

Which of the following events might you predict to occur if the tilt of Earthʹs axis relative to its plane of orbit was increased 33.5 degrees? A) Summers and winters in the United States would likely become warmer and colder, respectively. B) Winters and summers in Australia would likely become less distinct seasons. C) Seasonal variation at the equator might decrease. D) Both northern and southern hemispheres would experience summer and winter at the same time. E) Both poles would experience massive ice melts

a

Imagine some cosmic catastrophe jolts Earth so that its axis is perpendicular to the orbital plane between Earth and the sun. The most obvious effect of this change would be A) the elimination of tides. B) an increase in the length of night. C) an increase in the length of a year. D) a decrease in temperature at the equator. E) the elimination of seasonal variation.

e

The main reason polar regions are cooler than the equator is because A) there is more ice at the poles. B) sunlight strikes the poles at an lower angle. C) the poles are farther from the sun. D) the poles have a thicker atmosphere. E) the poles are permanently tilted away from the sun.

b

Which of the following environmental features might influence microclimates? A) a discarded soft-drink can B) a tree C) a fallen log D) a stone E) all of the above

e

The success with which plants extend their range northward following glacial retreat is best determined by A) whether there is simultaneous migration of herbivores. B) their tolerance to shade. C) their seed dispersal rate. D) their size. E) their growth rate.

c

As climate changes because of global warming, speciesʹ 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

Which of the examples below provides appropriate abiotic and biotic factors that might determine the distribution of the species in question? A) The amount of nitrate and phosphate in the soil and wild flower abundance and diversity B) The number of frost-free days and competition between species of introduced grasses and native alpine grasses C) Increased predation and decreased food availability and a prairie dog population after a prairie fire D) Available sunlight and increased salinity in the top few meters of the ocean and the abundance and diversity of phytoplankton communities E) The pH and dissolved oxygen concentration and the streams in which brook trout can live

b

A certain species of pine tree survives only in scattered locations at elevations above 2,800 m 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

How would an ecologist likely explain the expansion of the cattle egret? A) The areas to which the cattle egret has expanded have no cattle egret parasites. B) Climatic factors, such as temperature and precipitation provide suitable habitat for cattle egrets. C) There are no natural predators for cattle egrets in the New World, so they continue to expand their range. D) A habitat left unoccupied by native herons and egrets met the biotic and abiotic requirements of the cattle egret transplants and their descendants. E) The first egrets to colonize South America evolved into a new species capable of competing with the native species of herons and egrets.

d

Species introduced to new geographic locations A) are usually successful in colonizing the area. B) always spread because they encounter no natural predators. C) increase the diversity and therefore the stability of the ecosystem. D) can out-compete and displace native species for biotic and abiotic resources. E) are always considered pests by ecologists

d

Which of the following organisms is the most likely candidate for geographic isolation? A) sparrow B) bat C) squirrel D) salt-water fish E) land snail

e

Generalized global air circulation and precipitation patterns are caused by A) rising, warm, moist air masses cool and release precipitation as they rise and then at high altitude, cool and sink back to the surface as dry air masses after moving north or south of the tropics. B) air masses that are dried and heated over continental areas that rise, cool aloft, and descend over oceanic areas followed by a return flow of moist air from ocean to land delivering high amounts of precipitation to coastal areas. C) polar, cool, moist high pressure air masses from the poles that move along the surface, releasing precipitation along the way to the equator where they are heated and dried. D) the revolution of the Earth around the sun. E) Mountain ranges that deflect air masses containing variable amounts of moisture.

a

Air masses formed over the Pacific Ocean are moved by prevailing westerlies where they encounter extensive north-south mountain ranges, such as the Sierra Nevada and the Cascades. Which statement best describes the changes that these air masses undergo? A) The cool, moist Pacific air heats up as it rises, releasing its precipitation as it passes the tops of the mountains, and this warm, now dry air cools as it descends on the leeward side of the range. B) The warm, moist Pacific air rises and cools, releasing precipitation as it moves up the windward side of the range, and this cool, now dry air mass heats up as it descends on the leeward side of the range. C) The cool, dry Pacific air heats and picks up moisture from evaporation of the snowcapped peaks of the mountain range, releasing this moisture as precipitation as the air cools as it descends on the leeward side of the range. D) These air masses are blocked by these mountain ranges producing high annual amounts of precipitation on the windward sides of these mountain ranges. E) These air masses remain essentially unchanged in moisture content and temperature as they pass over these mountain ranges.

b

Experts in deer ecology generally agree that population sizes of deer that live in temperate climates are limited by winter snow. The deer congregate in ʺyardingʺ areas under evergreen trees because venturing out to feed in winter is energetically too expensive when snowfall depths accumulate to above 40 cm. Deer often stay yarded until the spring thaw. Snow depth over 40 inches for more than 60 days results in high mortality due to starvation. This observation best illustrates which of the following principles about factors that limit distribution of organisms? A) Abiotic factors, such as weather extremes, ultimately limit distribution. B) Organisms will face extinction unless they adapt to conditions or evolve new mechanisms for survival. C) Environmental factors are limiting not only in amount but also in longevity. D) Daily accumulations in snow depth gradually add up to cause increased deer mortality. E) Temporary extremes in weather conditions usually result in high mortality in the deer population.

c

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

b

The benthic zone in an aquatic biome A) often supports communities of organisms that feed largely on detritus. B) supports communities of highly motile animals. C) is where one would most expect to find a thermocline. D) has wider seasonal fluctuations in temperature than other aquatic zones. E) is always devoid of light.

a

Where would an ecologist find the most phytoplankton in a lake? A) profundal zone B) benthic zone C) photic zone D) oligotrophic zone E) aphotic zone

c

Phytoplankton is most frequently found in which of the following zones? A) oligotrophic B) photic C) benthic D) abyssal E) aphotic

b

You are planning a dive in a lake, and are eager to observe not many underwater organisms but be able to observe them both close up and far away. You would do well to choose A) an oligotrophic lake. B) an eutrophic lake. C) a relatively shallow lake. D) a nutrient-rich lake. E) a lake with consistently warm temperatures.

a

You are interested in studying how organisms react to a gradient of a variety of abiotic conditions and how they coexist in this gradient. The best location in which to conduct such a study is A) a grassland. B) an intertidal zone. C) a river. D) tropical forest. E) an eutrophic lake.

b

Which of the following statements about the ocean pelagic biome is true? A) The ocean is a vast, deep storehouse that always provides sustenance; it is the next ʺfrontierʺ for feeding humanity. B) Because it is so immense, the ocean is a uniform environment. C) More photosynthesis occurs in the ocean than in any other biome. D) Pelagic ocean photosynthetic activity is disproportionately low in relation to the size of the biome. E) The most abundant animals are unicellular zooplankton.

d

Coral animals A) are a diverse group of cnidarians often forming mutualistic symbiotic relationships with dinoflagellate algae. B) are predominantly photosynthetic, multicellular algae. C) can tolerate low oxygen and nutrient levels, and varying levels of salinity. D) can only survive in tropical waters 30oC and above. E) build coral reefs by glueing sand particles together.

a

If a meteor impact or volcanic eruption injected a lot of dust into the atmosphere and reduced the sunlight reaching Earthʹs surface by 70% for one year, all of the following marine communities most likely would be greatly affected except A) deep-sea vent communities. B) coral reef communities. C) benthic communities. D) pelagic communities. E) estuary communities.

a

Which of the following is not true about estuaries? A) Estuaries are often bordered by mudflats and salt marshes. B) Estuaries contain waters of varying salinity. C) Estuaries support a variety of animal life that humans consume. D) Estuaries usually contain no or few producers. E) Estuaries support many semiaquatic species.

d

Which of the following statements best describes the effect of climate on biome distribution? A) Knowledge of annual temperature and precipitation is sufficient to predict which biome will be found in an area. B) Fluctuation of environmental variables is not important if areas have the same annual temperature and precipitation means. C) It is not only the average climate that is important in determining biome distribution, but also the pattern of climatic variation. D) Temperate forests, coniferous forests, and grasslands all have the same mean annual temperatures and precipitation. E) Correlation of climate with biome distribution is sufficient to determine the cause of biome patterns.

c

Probably the most important factor(s) affecting the distribution of biomes is (are) A) wind and ocean water current patterns. B) species diversity. C) proximity to large bodies of water D) climate. E) day length and rainfall

d

In the development of terrestrial biomes, which factor is most dependent on all the others? A) the species of colonizing animals B) prevailing temperature C) prevailing rainfall D) mineral nutrient availability E) soil structure

a

An area in which different terrestrial biomes grade into each other is known as a(n) A) littoral zone. B) vertically stratified canopy. C) ecotone. D) abyssal zone. E) cline.

c

Two plant species live in the same biome but on different continents. Although the two species are not at all closely related, they may appear quite similar as a result of A) parallel evolution. B) convergent evolution. C) allopatric speciation. D) introgression. E) gene flow.

b

In which of the following terrestrial biome pairs are both dependent upon periodic burning? A) tundra and coniferous forest B) chaparral and savanna C) desert and savanna D) tropical forest and temperate broadleaf forest E) grassland and tundra

b

Fire suppression by humans A) will always result in an increase in the species diversity in a given biome. B) can change the species composition within biological communities. C) will result ultimately in sustainable production of increased amounts of wood for human use. D) is necessary for the protection of threatened and endangered forest species. E) is a management goal of conservation biologists to maintain the healthy condition of biomes.

b

Which of the following statements best describes the interaction between fire and ecosystems? A) The chance of fire in a given ecosystem is highly predictable over the short term. B) Many kinds of plants and plant communities have adapted to frequent fires. C) The prevention of forest fires has allowed more productive and stable plant communities to develop. D) Chaparral communities have evolved to the extent that they rarely burn. E) Fire is unnatural in ecosystems and should be prevented.

b

Which biome is able to support many large animals despite receiving moderate amounts of rainfall? A) tropical rain forest B) temperate forest C) chaparral D) taiga E) savanna

e

Tropical grasslands with scattered trees are also known as A) taigas. B) tundras. C) savannas. D) chaparrals. E) temperate plains

c

Which type of biome would most likely occur in a climate with mild, rainy winters and hot, dry summers? A) desert B) taiga C) temperate grassland D) chaparral E) savanna

d

In which community would organisms most likely have adaptations enabling them to respond to different photoperiods? A) tropical forest B) coral reef C) savanna D) temperate forest E) abyssal

d

The growing season would generally be shortest in which of the following biomes? A) savanna B) temperate broadleaf forest C) temperate grassland D) tropical rain forest E) coniferous forest

e

Trees are not usually found in the tundra biome because of A) insufficient annual precipitation. B) acidic soils. C) extreme winter temperatures. D) overbrowsing by musk ox and caribou. E) permafrost

e

If global warming continues at its present rate, which biomes will likely take the place of the coniferous forest (taiga)? A) tundra and polar ice B) temperate broadleaf forest and grassland C) desert and chaparral D) tropical forest and savanna E) chaparral and temperate broadleaf forest

b

Which of the following areas of study focuses on the exchange of energy, organisms, and materials between ecosystems? A) population ecology B) organismal ecology C) landscape ecology D) ecosystem ecology E) community ecology

c

If Earthʹs axis of rotation suddenly became perpendicular to the plane of its orbit, the most predictable effect would be A) no more night and day. B) a big change in the length of the year. C) a cooling of the equator. D) a loss of seasonal variation at high latitudes. E) the elimination of ocean currents

d

When climbing a mountain, we can observe transitions in biological communities that are analogous to the changes A) in biomes at different latitudes. B) at different depths in the ocean. C) in a community through different seasons. D) in an ecosystem as it evolves over time. E) across the United States from east to west.

a

The oceans affect the biosphere in all of the following ways except A) producing a substantial amount of the biosphereʹs oxygen. B) removing carbon dioxide from the atmosphere. C) moderating the climate of terrestrial biomes. D) regulating the pH of freshwater biomes and terrestrial groundwater. E) being the source of most of Earthʹs rainfall.

d

Which lake zone would be absent in a very shallow lake? A) benthic zone B) aphotic zone C) pelagic zone D) littoral zone E) limnetic zone

b

Which of the following is true with respect to oligotrophic lakes and eutrophic lakes? A) Oligotrophic lakes are more subject to oxygen depletion. B) Rates of photosynthesis are lower in eutrophic lakes. C) Eutrophic lake water contains lower concentrations of nutrients. D) Eutrophic lakes are richer in nutrients. E) Sediments in oligotrophic lakes contain larger amounts of decomposable organic matter.

d

Which of the following is characteristic of most terrestrial biomes? A) annual average rainfall in excess of 250 cm B) a distribution predicted almost entirely by rock and soil patterns C) clear boundaries between adjacent biomes D) vegetation demonstrating stratification E) cold winter months

d

Which of the following biomes is correctly paired with the description of its climate? A) savanna-low temperature, precipitation uniform during the year B) tundra-long summers, mild winters C) temperate broadleaf forest-relatively short growing season, mild winters D) temperate grasslands-relatively warm winters, most rainfall in summer E) tropical forests-nearly constant day length and temperature

e

Suppose the number of bird species is determined mainly by the number of vertical strata found in the environment. If so, in which of the following biomes would you find the greatest number of bird species? A) tropical rain forest B) savanna C) desert D) temperate broadleaf forest E) temperate grassland

a