answer to ch 5 test eesa01

Environment: The Science Behind the Stories, 4e (Withgott) Chapter 5 Environmental Systems and Ecosystem Ecology

5.1 Graph and Figure Interpretation Questions

Use Figure 5.1 to answer the following questions.

1) This graph helps to explain ________.A) why the open ocean is so productiveB) why cultivated lands are a logical choice to replace rainforestsC) why we need to be concerned with damage to rainforests and coral reefsD) why tundra has such high net primary productivity of biomassE) the importance of desertsAnswer: CDiff: 2Objective: 5.1 Earth's environmental systems

1Copyright © 2011 Pearson Education, Inc.

2) Recall that areas with high net primary productivity not only produce high levels of biomass rapidly, they also take up large amounts of CO2 and give off large amounts of oxygen. What is the likely result of the increasing amounts of sediments and fertilizers in the major rivers emptying into oceans and affecting algal beds, reefs, swamps, and estuaries?A) Productivity in these areas will increase permanently, leading to more CO2 uptake and more oxygen released.B) Eutrophication, followed by hypoxia, is a likely result, ultimately leading to less CO2 uptake and less oxygen released.C) Eutrophication, followed by hypoxia, is a likely result, ultimately leading to more CO2 uptake and more oxygen released.D) Eutrophication, followed by hypoxia, is a likely result, ultimately leading to less CO2 uptake and more oxygen released.E) Fisheries will improve as the extra nutrients feed shellfish and fish.Answer: BDiff: 2Objective: 5.3 Human impacts on systems and cycles

3) Overall, it appears that biomes with more available fresh water ________.A) tend to have less productivity than those without much freshwaterB) tend to have about the same productivity as those without much freshwaterC) tend to have more productivity than those without much freshwaterD) don't differentiate between freshwater as rainfall and freshwater as ice in glaciersE) No real conclusions can be drawn.Answer: CDiff: 2Objective: 5.2 Biogeochemical cycles


5.2 Matching Questions

Match the following.

A) hydrosphereB) ecosystemC) transpirationD) water tableE) evaporationF) biosphereG) atmosphereH) biomeI) lithosphereJ) aquiferK) biomassL) precipitation

1) A large ecological unit influenced by temperature, elevation, precipitation, and latitudeDiff: 1Objective: 5.1 Earth's environmental systems

2) Matter contained in living organismsDiff: 1Objective: 5.1 Earth's environmental systems

3) The solid earth beneath our feetDiff: 1Objective: 5.1 Earth's environmental systems

4) The process by which water moves from Earth's surface (such as in lakes or rivers) to the atmosphereDiff: 1Objective: 5.2 Biogeochemical cycles

5) Release of water vapor by plants through their leavesDiff: 1Objective: 5.2 Biogeochemical cycles

6) Upper limit of groundwater in soil or rocksDiff: 1Objective: 5.2 Biogeochemical cycles

7) Water returns from the clouds to Earth's surface asDiff: 1Objective: 5.2 Biogeochemical cycles

Answers: 1) H 2) K 3) I 4) E 5) C 6) D 7) L


5.3 Multiple-Choice Questions

1) Any network of relationships among a group of components, which interact with and influence one another through exchange of matter and/or information, is referred to as ________.A) an interchangeB) a systemC) an ecosystemD) an environmental collaborationE) hierarchyAnswer: BDiff: 1Objective: 5.1 Earth's environmental systems

2) A system receiving inputs and producing outputs without undergoing any changes in size or function is said to be in ________.A) static controlB) environmental balanceC) harmonic resonanceD) normal balanceE) dynamic equilibriumAnswer: EDiff: 1Objective: 5.1 Earth's environmental systems

3) Cattle on an open range, in some areas, may compact fragile soils while grazing. This can damage plant roots, leading to fewer, smaller plants, which may in turn cause cattle to graze more and work harder to obtain food. This is an example of a ________.A) positive feedback loopB) negative feedback loopC) homeostatic systemD) dynamic equilibriumE) food webAnswer: ADiff: 2Objective: 5.3 Human impacts on systems and cycles


4) The eutrophication that has taken place in the Gulf of Mexico and other locations appears to be due to ________.A) global warming from human use of fossil fuelsB) pesticide use along the waterwaysC) heavy metals dumped in the sewageD) weather alone, because it is only obvious in the summerE) excess nutrients from fertilizersAnswer: EDiff: 2Objective: 5.3 Human impacts on systems and cycles

5) The physical, abiotic components of our planet can be divided into the ________.A) geosphere and atmosphereB) lithosphere, hydrosphere, and atmosphereC) lithosphere, biosphere, and atmosphereD) lithosphere, hydrosphere, biosphere, and atmosphereE) centrosphere, geosphere, biosphere, and atmosphereAnswer: BDiff: 2Objective: 5.1 Earth's environmental systems

6) A natural ecosystem, undamaged by human activity, is ________.A) a closed system of organic materials and energy; everything is recycledB) an open system of organic materials and energy C) an open system of organic and inorganic materials and energyD) a closed system of organic and inorganic materials and energy; everything is recycledE) an open system of inorganic materials and energyAnswer: CDiff: 2Objective: 5.1 Earth's environmental systems

7) The swamplands of extreme southern Louisiana, which contain elements of both the forests and coastal marshes, could be called ________.A) a superbiomeB) an ecotoneC) a dead zoneD) a closed ecosystemE) an abiotic systemAnswer: BDiff: 2Objective: 5.1 Earth's environmental systems


8) A small section of prairie grasses, over a year, produces enough biomass to feed insects, mice, rabbits, birds, deer, antelope, and a host of decomposers. The amount of food potentially available to the herbivores is the ________.A) net primary productionB) gross primary productionC) secondary productionD) respirationE) food chainAnswer: ADiff: 2Objective: 5.1 Earth's environmental systems

9) The rate at which biomass becomes available to consumers is termed ________.A) gross primary productionB) ecosystem productivityC) grossulosity factorD) net densityE) net primary productivityAnswer: EDiff: 2Objective: 5.1 Earth's environmental systems

10) The biosphere consists of the ________.A) water, saltwater, and freshwater in surface bodies and the atmosphereB) solid earth beneath our feetC) sum of all the planet's living organisms and the abiotic portions of the environmentD) air surrounding our planetE) abiotic portions of the environmentAnswer: CDiff: 1Objective: 5.1 Earth's environmental systems

11) Ecotones are the ________.A) sounds that animal communities make in ecosystemsB) interactive behaviors leading to communicationC) areas between territories of organismsD) studies of specific biomes by ecologistsE) transitional zones between ecosystemsAnswer: EDiff: 1Objective: 5.1 Earth's environmental systems


12) Examining areas from the landscape scale, termed landscape ecology, is useful because ________.A) humans have not yet caused alterations to landscapesB) the dynamics of animals result in localized problemsC) the role of ecosystems is often overstatedD) multiple ecosystems may exist in a single area with many transitional zonesE) it helps to define the entire closed systemAnswer: DDiff: 2Objective: 5.1 Earth's environmental systems

13) Macronutrients ________.A) are large molecules necessary for making macromoleculesB) are required in large amounts for organisms to surviveC) are the only nutrients that can be tracked in nutrient cyclesD) can only be taken up by plants from rock cyclesE) are what large predators eatAnswer: BDiff: 1Objective: 5.1 Earth's environmental systems

14) Experiments done in coastal regions of oceans throughout the world have demonstrated that ________.A) the same few micronutrients limit growth everywhereB) only one micronutrient, nitrogen, limits growth everywhereC) only one micronutrient, phosphorus, limits growth everywhereD) different micronutrients appear to limit growth in different placesE) the only micronutrient that is important is carbonAnswer: ADiff: 2Objective: 5.1 Earth's environmental systems

15) The largest pools of carbon in the carbon cycle are ________.A) freshwater systems and oceansB) plants and animalsC) sedimentary rock and fossil fuelsD) atmosphereE) hydrosphereAnswer: CDiff: 2Objective: 5.2 Biogeochemical cycles


16) The origin of all phosphorus in biological tissues is ________.A) volcanic activitiesB) atmospheric phosphorus gas C) phosphorus weathered from rockD) phosphorus dissolved in the ocean and taken up by shellfishE) phosphorus in animal bonesAnswer: CDiff: 2Objective: 5.2 Biogeochemical cycles

17) The origin of all nitrogen in biological tissues is ________.A) earthquake activitiesB) atmospheric N2 gas C) nitrogen weathered from rockD) lightningE) volcanoesAnswer: BDiff: 2Objective: 5.2 Biogeochemical cycles

18) Nitrogen fixation is a process that makes nitrogen available to plants and is carried out by ________.A) photosynthesisB) volcanic eruptionsC) parasitic bacteriaD) nitrogen gas dissolving in freshwater and in the oceanE) mutualistic and free-living bacteriaAnswer: EDiff: 2Objective: 5.2 Biogeochemical cycles

19) Humans have dramatically altered the rate of nitrogen fixation into forms usable by autotrophs ________.A) due to the burning of fossil fuels to meet our energy needsB) because of the erosion of farmlands through poor agricultural practicesC) as we produce synthetic fertilizers and apply them to crops, lawns, and parksD) by using antibiotics to reduce the numbers of denitrifying bacteriaE) by selectively removing leguminous plantsAnswer: CDiff: 3Objective: 5.3 Human impacts on systems and cycles


20) Aquifers are ________.A) natural ponds and lakesB) recharge lakes at water quality facilitiesC) underground water reservoirsD) the result of transpirationE) oceansAnswer: CDiff: 2Objective: 5.2 Biogeochemical cycles

21) By damming rivers and using methods such as flood irrigation, we are ________.A) increasing evaporationB) increasing the water tableC) decreasing the water tableD) decreasing transpirationE) increasing transportation Answer: ADiff: 3Objective: 5.3 Human impacts on systems and cycles

22) Human beings have dramatically altered the flux rate of nitrogen from ________.A) the atmosphere to various pools on the earth's surfaceB) from soils to the atmosphereC) proteins to inorganic ions in soilsD) oceans to soilsE) producers to consumers through increased wildfiresAnswer: ADiff: 2Objective: 5.2 Biogeochemical cycles

23) Ecological modeling ________.A) is a form of ecosystem restorationB) is based on natural ecosystems and helps us design sustainable management strategiesC) has so far proven useless in predicting ecological eventsD) requires the dismantling and dissecting of a functioning ecosystem E) is used by evolutionary biologist to predict future evolutionary eventsAnswer: BDiff: 2Objective: 5.1 Earth's environmental systems


24) Ecological modelling can help us ________ ecosystem services.A) control the growth ofB) create many newC) understand the system functions of and sustainably useD) decrease the cost of maintainingE) replace destroyedAnswer: CDiff: 2Objective: 5.3 Human impacts on systems and cycles

25) In an eutrophic aquatic ecosystem dissolved oxygen ________ and dissolved macronutrients ________.A) increases/deceaseB) increases/increaseC) decreases/decreaseD) decreases/increaseE) remains stable/increasesAnswer: DDiff: 2Objective: 5.3 Human impacts on systems and cycles

5.4 Essay Questions

1) Compare and contrast positive and negative feedback loops. Give an example of each and how common each is in natural systems.Answer: A system's output can serve as input to that same system, a circular process described as a feedback loop. In a negative feedback loop, output pushing the system in one direction acts as input that moves the system in another direction. The output and input essentially neutralize one another, stabilizing the system. An example would be the regulation of our body temperature. Negative feedback loops are relatively common in nature. In a positive feedback loop, inputs don't stabilize a system but drive them further toward one extreme or another. An example of this process in natural systems is erosion. These are relatively rare in nature but are common in natural systems altered by human actions.Diff: 2Objective: 5.1 Earth's environmental systems


2) Differentiate between an open and a closed system. If possible, give a specific and somewhat detailed example of each. Do both exist in nature? Why or why not? Answer: A closed system is one that is isolated and self-contained. It is hypothetical and allows scientists to grapple with complex systems. An open system is one that exchanges energy, matter, and information with another system. The Mississippi River is an open system that interacts with all aquatic systems, terrestrial systems, and atmospheric systems from its origin to the Gulf of Mexico. It is affected by all sources of pollution, fertilizer, temperature change, and other human impacts that can access its waters. Closed systems do not exist in nature. Even a system as closed as a desktop computer becomes an open system when plugged into the wall socket that is in contact with the electricity that runs through an entire local community. Matter may recycle through a system, but energy must be constantly input from an external source, such as the sun.Diff: 3Objective: 5.1 Earth's environmental systems

3) Give a brief overview of the carbon cycle. Include the source of carbon that enters ecosystems, how it moves through ecosystems, what it is used for, and where it is ultimately deposited. What part of this cycle is believed to contribute to global warming?Answer: Plants take up CO2 from the atmosphere and then incorporate the carbon into their tissue. Animals then eat plants and gain carbon. Carbon is used for all the tissues and molecules of living organisms, such as carbohydrates, fats, and proteins, and as an essential ingredient in DNA. When animals and plants die, their tissues are metabolized by decomposers and much partially degraded biomass (especially from plants) is then deposited into soils. At each stage along the way, some carbon is released back to the atmosphere as carbon dioxide. The use of fossil fuels (previously undecomposed organic materials) causes stored CO2 to be released to the atmosphere. This is occurring at very high rates and is contributing to global warming.Diff: 3Objective: 5.2 Biogeochemical cycles

4) Human activity has affected every aspect of the nitrogen cycle. List the ways that humans have altered nitrogen content starting with how nitrogen becomes available to producers, where it goes, and what impacts it has. What are the concerns for the future? Answer: Humans have spent a great deal of money on producing and distributing nitrogen and have doubled the amount of nitrogen available for use by plants. The Haber-Bosch process allows us to fix nitrogen into usable molecules. We have increased the amount of nitrogen that makes its way into waterways, mostly as runoff from fertilizer. This has caused alterations in terrestrial community composition and eutrophication in water systems. We have also increased the distribution of nitrogen through atmospheric pollution, primarily from nitrogen oxides resulting from burning fossil fuels, that then comes down as acid rain. Concerns for the future include climate change through increased concentrations of nitrous oxide, a greenhouse gas, depleted nutrients from soils, and acidified surface water and soils.Diff: 3Objective: 5.3 Human impacts on systems and cycles


5) Human activity has affected every aspect of the water cycle. List four ways that humans have altered the water cycle. What are the major concerns for the future? Answer: First, humans have dammed rivers to create reservoirs, resulting in increased evaporation and infiltration of surface water into aquifers. Second, we have removed vegetation from many areas so infiltration into the soil, transpiration, and return of water to the atmosphere have all slowed, increasing runoff and erosion. Third, our agricultural methods, such as flood irrigation, have resulted in the depletion of surface waters. Finally, we emit pollutants into the atmosphere that subsequently come down in rainwater.

The greatest concern for the future will be shortages of potable water. Shortages in specific areas of many countries are already evident. Groundwater is being removed at high rates due to agriculture and manufacturing in this country. Water tables in previously plentiful aquifers are dropping at rapid rates and may ultimately limit agricultural production and manufacturing, as well as the availability of clean, fresh water supplies for people worldwide.Diff: 3Objective: 5.3 Human impacts on systems and cycles

6) Describe the hypotheses and the results obtained in the FACE (Free Air Carbon Dioxide Enrichment project.Answer: This ambitious project was designed to determine whether forests could be a possible factor in removing and sequestering CO2 in a future challenged by global climate change. To test this hypothesis, forests in several US and international locations were dosed with huge amounts of CO2 which simulated a 50% rise in ambient levels. Some of the things learned so far are that elevated CO2 levels increase photosynthesis and tree growth but that the rates of growth eventually slow and level off. The increased biomass still falls to the forest floor where it is metabolized by decomposers, releasing the fixed carbon back into the atmosphere as CO2. Also, the elevated CO2 levels may delay leaf death, resulting in higher tree mortality from frost damage in winter. Finally, in some cases the insect pests of forest trees tended to increase under experimental conditions.Diff: 2Objective: 5.3 Human impacts on systems and cycles

7) What factors contribute to the "dead zone" in the waters off the Gulf of Mexico?Answer: There has been a rapid acceleration of anthropogenic fixing of atmospheric nitrogen and releasing it into the lithosphere. This is manifested through fertilizer runoff into the Mississippi watershed and thence into the Gulf of Mexico. There excess nitrogen and phosphorus, combined with more nutrient loading from sewage discharge, has contributed to algal blooms with a subsequent rise in plant biomass. This the excess biomass is partly eaten by consumers but a large amount sediments out as dead material and is metabolized by benthic decomposers. All this increased aerobic metabolism depletes the Gulf waters of essential dissolved oxygen, leading to a hypoxic dead zone. Diff: 2Objective: 5.3 Human impacts on systems and cycles


8) Define the term emergent properties and give an example from a natural system.Answer: Emergent properties are characteristics that are not evident in the system's components (the whole is greater than the sum of its parts). The component parts of a tree (leaves, branches, roots, bole) do not lead to the whole tree's emergent properties as a source of shade for understory vegetation, a home for birds and insects, a rich resource filled with nectar and pollen during flowering season, and/or a source of food for many organisms in the form of fruits or nuts.Diff: 2Objective: 5.1 Earth's environmental systems

9) What are the anthropogenic sources of phosphorus, and why are they a problem?Answer: The major anthropogenic source of phosphorus is effluent from sewage treatments, which tends to be phosphate rich. Fertilizers also provide large amounts of anthropogenic phosphorus, and many detergents play a part as well. Introduction of phosphates from all of these sources into surface waters causes eutrophication and algal growth, leading to murkier waters and changes in the structure and function of ecosystems.Diff: 2Objective: 5.3 Human impacts on systems and cycles

10) How and for what is GIS software used?Answer: GIS (geographic information system) software is used by landscape ecologists to analyze and visualize how geographic elements of a landscape are arrayed spatially. The elements can be arranged as layers to form a composite map, useful for mapping niches of various species and establishing management strategies for any landscape, natural or urban.Diff: 2Objective: 5.1 Earth's environmental systems


5.5 Scenario-Based Questions

Read the following scenario and answer the questions below.

In the early years of the 20th century there were lush stands of tall grasses in the valley on the east side of the Chiricahua Mountains in Arizona, stretching to Mexico on the south and New Mexico on the east. Dramatic summer rainstorms dumped huge amounts of water, very quickly, on the rocky upper slopes. The water ran down the slopes and into the grasslands, where it quickly soaked into the soft, porous soil. Cattle ranching was in full swing, utilizing the rich grasses, but the ranchers did not appreciate the multitudes of prairie dogs that lived in the grasslands. Cattle would stumble in the holes, break legs, and die of starvation. In addition, many ranchers were convinced that the prairie dogs would destroy the grasses because they directly competed with the cattle for food. The ranchers had already done away with most predators that might possibly affect cattle, and now they turned their attention to the prairie dogs. The ranchers become a part of a new federally sponsored movement to poison the grassland prairie dogs. This movement took root and spread through the 1920s and 1930s.

1) Prairie dogs constantly dig through the soil, making new burrows. They eat the grasses, roots and all. This probably contributes to ________.A) the grassroots being subject to diseasesB) the soil being loose and to little nutrient cycling, causing grasses to fall overC) the soil hardening during rains and to little nutrient cycling, causing grasses to dieD) the soils eroding and losing nutrients over time, causing the grasses to dieE) the soil being loose and to nutrient cycling, allowing new grass roots to grow and prosperAnswer: EDiff: 2Objective: 5.1 Earth's environmental systems

2) When the rains came down on the rocky mountainsides, the water ran down into the grasslands where the prairie dogs were active and ________.A) quickly ran off the loose soil, eroding the soilB) quickly evaporated, drying the loose soilC) quickly soaked into the loose soil, watering the grassesD) gathered atop the loose soil, forming large muddy spotsE) formed pondsAnswer: CDiff: 3Objective: 5.2 Biogeochemical cycles


3) In the late 1800s and early 1900s farmers and ranchers slaughtered coyotes, bobcats, wolves, mountain lions, eagles, and rattlesnakes, trying to protect their cattle. One direct result may have been ________.A) a decrease in soil qualityB) an increase in predationC) an increase in soil qualityD) an increase in the prairie dog populationE) a decrease in the prairie dog populationAnswer: DDiff: 2Objective: 5.3 Human impacts on systems and cycles

4) Once the prairie dogs were poisoned and no longer a part of the ecosystem, which of the following probably occurred?A) Soils slowly became looser because of the cattle, so soil moisture increased.B) Soils slowly compacted because of the cattle, so soil moisture decreased.C) Soils slowly became looser because of the cattle, so fewer nutrients were recycled.D) Soils slowly compacted because of the cattle, so soil moisture increased.E) Soils slowly became looser because of the cattle, so soil moisture decreased.Answer: BDiff: 2Objective: 5.2 Biogeochemical cycles

5) The ranchers now wanted to bring back the prairie dogs because they realized that ________.A) the prairie dogs kept the soil loose, so rain sank in and grasses grewB) the prairie dogs didn't eat grassC) the predators depended on the prairie dogsD) the cattle also ate the prairie dogs when grass was scarceE) the prairie dogs were part of the net secondary productivityAnswer: ADiff: 3Objective: 5.1 Earth's environmental systems


6) In a previous chapter you read about "keystone species." How do the prairie dogs in this story meet the definition of a keystone species? A) They don't meet the definition of a keystone species; the system did fine without them. The predators turned to cattle, and the grasses did better in the compact soil.B) Their burrows loosened the soil and served as homes for other species; they helped with nutrient recycling. They helped water sink into the soil and kept soil loose for grassroots. When they were removed, the system deteriorated.C) The availability of prairie dogs kept the predators in check; when they were removed, the predator populations grew dramatically. They kept the soil aerated and compact.D) When the prairie dogs were removed, the cattle declined; this meets the definition of a keystone species.E) Their burrows caused cattle to break their legs and die. This made them directly responsible for the welfare of another species, which meets the definition of a keystone species.Answer: BDiff: 3Objective: 5.1 Earth's environmental systems

7) Some of the conclusions that can be drawn from this scenario include that ________.A) Cattle improved the soils, contributing to this ecosystem.B) Predators were unimportant components of this ecosystem; their removal caused no subsequent problems.C) Prairie dogs were unimportant components of this ecosystem; their removal caused no subsequent problems.D) Once humans change one thing in an ecosystem, they may find unexpected results occurring elsewhere in the ecosystem.E) Prairie dogs were part of a negative feedback loop once they were removed.Answer: DDiff: 3Objective: 5.3 Human impacts on systems and cycles


answer to ch 5 test eesa01

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