Chapter 52

Which of the following statements regarding turnover in a lake is correct? A) In fall turnover, dense water at 4°C sinks and disturbs sediments in the benthic zone. B) In fall turnover, dense water at 4°C rises and disturbs sediments in the benthic zone. C) The surface water gets to 4°C only by cooling. D) Fall turnovers and spring turnovers are exactly the same.

A) In fall turnover, dense water at 4°C sinks and disturbs sediments in the benthic zone.

Which of the following is responsible for the differences in summer and winter temperature stratification of deep temperate zone lakes? A) Water is most dense 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.

A) Water is most dense at 4°C.

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

A) an oligotrophic lake

Which of the following types of organisms is likely to have the widest geographic distribution? A) bacteria B) songbirds C) bears D) lizards

A) bacteria

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) convergent evolution B) allopatric speciation C) introgression D) gene flow

A) convergent evolution

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 larger, more contiguous established populations to begin with B) produce well-provisioned seeds C) have seeds that become viable only after a forest fire D) disperse many seeds in close proximity to the parent tree

A) have larger, more contiguous established populations to begin with

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

A) in biomes at different latitudes

If an ecologist were studying the regional interactions among multiple populations of different species and how they influence the exchange of materials between their various environments, then this would be an example of which kind of research? A) landscape ecology B) population ecology C) global ecology D) ecosystem ecology

A) landscape ecology

The ocean ecosystems affect the biosphere by ________. I) producing a substantial amount of the biosphere's oxygen II) adding carbon dioxide to the atmosphere III) being the source of most of Earth's rainfall IV)regulating the pH of freshwater biomes and terrestrial groundwater A) only I and III B) only II and IV C) only I, II, and IV D) only I, II, and III

A) only I and III

Which statements about dispersal are accurate? I) Dispersal is a common component of the life cycles of plants and animals. II) Colonization of devastated areas after floods or volcanic eruptions primarily depends upon climate. III) Seeds are important dispersal stages in the life cycles of most flowering plants. IV)Dispersal occurs only on an evolutionary time scale. A) only I and III B) only II and IV C) only I, II, and IV D) only II, III, and IV

A) only I and III

The main reason polar regions are cooler than the equator is that ________. A) solar radiation strikes the poles at a lower angle and travels through more atmosphere B) the poles are farther from the sun than is the equator C) the polar atmosphere is thinner and contains fewer greenhouse gases D) the poles are permanently tilted away from the sun

A) solar radiation strikes the poles at a lower angle and travels through more atmosphere

Generalized global air circulation and precipitation patterns are caused by ________. A) solar radiation that warms moist air masses near the equator, which then cool and release precipitation as they rise, and then, at high altitude, move north or south of the tropics and sink back to the surface as dry air masses B) air masses that are dried and heated over continental areas, which then 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) solar radiation that warms dry air masses at the poles, causing them to sink toward the tropics, gain moisture, and then release it as precipitation.

A) solar radiation that warms moist air masses near the equator, which then cool and release precipitation as they rise, and then, at high altitude, move north or south of the tropics and sink back to the surface as dry air masses

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

A) temperate broadleaf forest and grassland

Which of the following examples demonstrate an ecological effect leading to an evolutionary effect? A) When seeds are not plentiful, trees produce more seeds. B) A few individuals with denser fur survive the coldest years of an ice age, and the offspring of the reproducing survivors of the ice age will likely have more dense fur. C) Fish that swim the fastest in running water catch the most prey and more easily escape predation. D) The insects that spend the most time exposed to sunlight have the most mutations from UV light, and thus evolve the fastest

B) A few individuals with denser fur survive the coldest years of an ice age, and the offspring of the reproducing survivors of the ice age will likely have more dense fur.

Which of the following investigations would shed the most light on the future distribution of organisms in temperate regions that are faced with climate change? A) Remove, to the mineral soil, all of the organisms from an experimental plot, and monitor the colonization of the area over time in terms of both species diversity and abundance. B) Look at the climatic changes that occurred since the last ice age and how species redistributed as glaciers melted, then make predictions on future distribution in species based on past trends. C) Compare and contrast the flora and fauna of warm/cold/dry/wet climates to shed light on how they evolved to be suited to their present-day environment. D) Quantify the impact of man's activities on present-day populations of threatened and endangered species to assess the rate of extirpation and extinction.

B) Look at the climatic changes that occurred since the last ice age and how species redistributed as glaciers melted, then make predictions on future distribution in species based on past trends.

Which of the following statements best describes the interaction between fire and ecosystems? A) The likelihood of a wildfire occurring 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 suppression of forest fires by humans has prevented certain communities, such as grasslands, from reaching their climax stage. D) Chaparral communities have evolved to the extent that they rarely burn.

B) Many kinds of plants and plant communities have adapted to frequent fires.

In areas of permafrost, stands of black spruce are frequently observed in the landscape, while other tree species are noticeably absent. Often these stands are referred to as "drunken forests" because many of the black spruce often "lean over" (that is, they are displaced from their normal vertical alignment). What is the most likely explanation for the unusual growth of these forests in this marginal habitat? A) Branches are adapted to absorb more carbon dioxide with this displaced alignment. B) Taproot formation is impossible, so trees developed shallow root beds. C) Trees are tilted so snow prevents them from breaking or tipping over. D) Trees tip so that they do not compete with each other for sunlight.

B) Taproot formation is impossible, so trees developed shallow root beds.

At 15-30°N, air masses formed over the Pacific Ocean are moved by prevailing westerlies, where they encounter extensive north-south mountain ranges. Which statement best describes the outcome of this encounter between a landform and an air mass? A) The cool, moist Pacific air heats as it rises, releasing its precipitation as it passes the tops of the mountains. This now warm and 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. This now cool and dry air mass heats up as it descends on the leeward side of the range. C) The cool, dry Pacific air heats up and picks up moisture from evaporation of the snowcapped peaks of the mountain range, releasing this moisture as precipitation when the air cools while descending on the leeward side of the range. D) These air masses are blocked by the mountain ranges, producing high annual amounts of precipitation on the windward sides of these mountain ranges.

B) The warm, moist Pacific air rises and cools, releasing precipitation as it moves up the windward side of the range. This now cool and dry air mass heats up as it descends on the leeward side of the range.

Subtropical plants are commonplace in Land's End, England, whose latitude is the equivalent of Labrador in coastal Canada, where the local flora is instead subarctic. Which statement best explains why this apparent anomaly exists between North America and Europe? A) Labrador does not get enough rainfall to support the subtropical flora found in Land's End. B) Warm ocean currents interact with England, whereas cold ocean currents interact with Labrador. C) Rainfall fluctuates greatly in England; rainfall is consistently high in Labrador. D) Labrador receives sunlight of lower duration and intensity than does Land's End.

B) Warm ocean currents interact with England, whereas cold ocean currents interact with Labrador.

What would happen to the seasons if 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) Winters and summers would be more severe.

A certain species of pine tree survives only in scattered locations at elevations above 2,800 meters in the western United States. To understand why this tree grows only in these specific places, an ecologist should ________. A) study the anatomy and physiology of this species B) investigate the various biotic and abiotic factors that are unique to high altitude C) analyze the soils found in the vicinity of these trees, looking for unique chemicals that may support their growth D) collect data on temperature, wind, and precipitation at several of these locations for a year

B) investigate the various biotic and abiotic factors that are unique to high altitude

In deep water, which of the following abiotic factors would most limit primary productivity? A) temperature B) light availability C) solute concentration D) chemical composition of the sea floor

B) light availability

Which of the following causes seasons on Earth? A) the variation in proximity of the Earth to the sun at different times of the year B) the constant tilt of the Earth, combined with its orbit around the sun C) the distance between the Earth and the sun in winter versus in the summer D) the variation or wobble of Earth's tilt during the year

B) the constant tilt of the Earth, combined with its orbit around the sun

If the direction of Earth's rotation reversed, the most predictable effect would be ________. A) an elimination of deserts and increase in tropics B) winds blowing from west to east along the equator C) a loss of seasonal variation at high latitudes D) the elimination of ocean currents

B) winds blowing from west to east along the equator

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 fail to freeze over in winter. B) An algal bloom of algae would result every spring. C) Lakes would suffer a nutrient depletion in surface layers. D) The pH of the lake would become increasingly alkaline.

C) Lakes would suffer a nutrient depletion in surface layers.

Which of the following statements can be accurately made about light in aquatic environments? A) Water equally reflects and absorbs all wavelengths of light. B) Longer wavelengths penetrate to greater depths. C) Light penetration largely limits the distribution of photosynthetic species. D) Most photosynthetic organisms avoid the surface where the light is too intense.

C) Light penetration largely limits the distribution of photosynthetic species.

For mountain ranges that are subjected to prevailing winds, why is the climate drier on the leeward (downwind) side? A) Deserts create dry conditions on the leeward side of mountain ranges. B) The sun illuminates the leeward side of mountain ranges at a more direct angle, converting to heat energy, which evaporates most of the water present. C) Pushed by the prevailing winds on the windward side, air is forced to rise, cool, condense, and drop its precipitation, leaving drier air to descend the leeward side. D) Air masses pushed by the prevailing winds are stopped by mountain ranges and the moisture

C) Pushed by the prevailing winds on the windward side, air is forced to rise, cool, condense, and drop its precipitation, leaving drier air to descend the leeward side.

Which of the following biomes spans the largest annual mean temperature range, but the narrowest mean precipitation range? A) tropical forest B) temperate forest C) desert D) taiga

C) desert

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

C) determine if dispersal is a key factor in limiting distribution of organisms

Which of these environmental factor(s) is/are the key determining factor(s) that control(s) the biotic structure of aquatic biomes? A) average annual air temperature and precipitation B) seasonal fluctuation of water temperature C) oxygen concentrations and nutrient levels D) salinity

C) oxygen concentrations and nutrient levels

Wetlands are standing bodies of freshwater, just like lakes and ponds. However, wetlands are different from lakes and ponds because wetlands have ________. A) emergent vegetation B) oxygen-poor water C) shallow water and emergent vegetation D) emergent vegetation and oxygen-poor water

C) shallow water and emergent vegetation

Suppose that 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) tundra B) savanna C) temperate broadleaf forest D) temperate grassland

C) temperate broadleaf forest

The success of plants extending their range northward following glacial retreat is primarily determined by ________. A) whether there is simultaneous migration of herbivores B) their tolerance to shade C) their seed dispersal rate D) their tolerance to cooler temperatures

C) their seed dispersal rate

Coral reefs occur on the southeast coast of the United States but not at similar latitudes on the southwest coast. Differences in which of the following most likely account for this? A) air temperatures driven by precipitation B) day length C) water temperatures driven by ocean currents D) salinity differences

C) water temperatures driven by ocean currents

Which aquatic biome listed here is one of the most productive on Earth, and why? A) deep-sea vent, warm water temperatures B) coral reef, diversity of organisms C) wetlands, nutrient rich high-moisture soils D) oligotrophic lake, clear water for light penetration

C) wetlands, nutrient rich high-moisture soils

Organisms evolve over generations to become adapted to the environmental conditions to which they are exposed. The diversity of organisms that occurs in any particular area thus may be largely determined by the abiotic factors limiting survivorship and reproduction of organisms in a region. Which of the following limit the range of Saguaro cactus in North America? I) pollinators II) sunlight III) precipitation IV)temperature A) only I and III B) only II, III, and IV C) only I, III, and IV D) I, II, III and IV

D) I, II, III and IV

A fish swimming into an estuary from a river would have which of the following as its greatest physiological challenge? A) The high water flow would make the fish expend more energy. B) The low oxygen content would give the fish difficulty in swimming aerobically. C) The temperature change would stress the fish by denaturing its proteins. D) The change in water solute content would challenge the osmotic balance of the fish.

D) The change in water solute content would challenge the osmotic balance of the fish.

What would be the effect on climate in the temperate latitudes if Earth were to slow its rate of rotation from a 24-hour period of rotation to a 48-hour period of rotation? A) Seasons would be longer and more distinct (colder winters and warmer summers). B) Large-scale weather events such as tornadoes and hurricanes would no longer be a part of regional climates. C) Winter seasons in both the northern and southern hemispheres would have more abundant and frequent precipitation events. D) There often would be a larger range between daytime high and nighttime low temperatures.

D) There often would be a larger range between daytime high and nighttime low temperatures.

Generally speaking, deserts are located in places where air masses are usually ________. A) tropical B) ascending C) at the start of trade winds D) descending

D) descending

Which of the following might be an investigation of microclimate? A) the effect of ambient temperature on the onset of caribou migration B) the seasonal population fluctuation of nurse sharks in coral reef communities C) competitive interactions among various species of songbirds during spring migration D) how sunlight intensity affects plant community composition in the zone where a forest transitions into a meadow

D) how sunlight intensity affects plant community composition in the zone where a forest transitions into a meadow

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) support biological communities similar to those found at lower elevations on similar south-facing slopes D) support biological communities similar to those found at higher elevations on similar south-facing slopes

D) support biological communities similar to those found at higher elevations on similar south-facing slopes

In the region of the Rocky Mountains, imagine that one local variety of Ponderosa pine (Pinus ponderosa) predominantly occurs between 5,000-8,500 feet in elevation, where it can best tolerate temperatures and precipitation. If future climate change in this region causes the temperature to increase and rainfall to decrease, then which of the following changes might an ecologist predict about the variety's range? A) that variety will occur at lower elevations B) that variety will occur at higher elevations C) that variety will occur at lower elevations and/or lower latitudes D) that variety will occur at higher elevations and/or higher latitudes

D) that variety will occur at higher elevations and/or higher latitudes

Turnover of water in temperate lakes during the spring and fall is caused 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

D) the changes in the density of water as seasonal temperatures change

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 a year C) a decrease in temperature at the equator D) the elimination of seasonal variation

D) the elimination of seasonal variation

In creating global climate patterns, which of the following factors is the primary cause of all of the other factors that are listed? A) precipitation differences between tropical and polar regions B) global ocean currents C) global wind patterns D) variation in the heating of Earth's surface

D) variation in the heating of Earth's surface

Which of the following is an important feature of most terrestrial biomes? A) annual average rainfall in excess of 250 centimeters B) a distribution predicted almost entirely by rock and soil patterns C) clear boundaries between adjacent biomes D) vegetation demonstrating vertical layering

D) vegetation demonstrating vertical layering

If you conclude that vegetation at every point on Earth exactly resembles the predicted biome distribution in a climograph, then ________. A) you are ignoring human land use changes or impacts, which have highly altered many regions within biomes B) the biome spanning the smallest combined ranges in precipitation and temperature is the tundra C) the biome most sensitive (in danger) from global warming is the desert D) you are ignoring the fact that local differences in soil, elevation, or topography can result in considerably different plant communities that are embedded within named biomes

D) you are ignoring the fact that local differences in soil, elevation, or topography can result in considerably different plant communities that are embedded within named biomes