Deck 25: Global Change

Question 1

The figure below shows the relative concentration of polychlorinated biphenyls (PCBs)in several members of a lake food web.
Although the lake trout and minnow are both fish, the lake trout is more contaminated. Why?

A)Lake trout are bigger so their bodies can store a greater quantity of PCBs.
B)PCBs dissolve poorly in water but readily in fat; lake trout have a higher percentage of body fat than minnows.
C)Lake trout are large and long-lived; when they respire they pass water over their gills allowing the PCBs in the lake to accumulate in their bodies.
D)Lake trout fed on minnows, whereas minnows fed on crustaceans.

Answer 1

D

Question 2

The industrial production of fertilizers by humans

A)removes carbon dioxide from the atmosphere.
B)is causing a hole in the ozone layer.
C)has greatly increased the extent of human participation in the nitrogen cycle.
D)reduces the amount of acid rain.

Answer 2

C

Question 3

One of the major effects of an increase in atmospheric carbon dioxide is

A)an increase in average global temperature.
B)cooler average temperatures as carbon dioxide reflects sunlight back into space.
C)an acceleration of the depletion of ozone.
D)an increase in the pH of oceans and lakes.

Answer 3

A

Question 4

Why do synthetic chemicals and metals tend to bioaccumulate so readily?

A)These substances are so rare in natural environments that living organisms have developed very efficient methods of collecting them.
B)Natural reservoirs are so large that when expressed as a concentration putting the same amount into an organism will always produce an elevated value.
C)Synthetic chemicals often have no nutritional value, so they are simply stored in the body and passed on when an organism is eaten.
D)They are stable chemicals and are accumulated in the cells of organisms more rapidly than they can be removed.

Question 5

The release of chlorofluorocarbons (CFCs)into the atmosphere has caused a(n)

A)increase in the amount of usable nitrogen.
B)decrease in the amount of ultraviolet light reaching Earth.
C)increase in acid rainfall.
D)decrease in Earth's ozone layer.

Question 6

Although not directly toxic to living organisms, chlorofluorocarbons (CFCs)have had unanticipated impacts on the atmosphere. The ecological impacts of CFCs will be

A)relatively benign because even as secondary pollutants their toxicity remains low.
B)limited to the terrestrial ecosystem only.
C)limited to high-altitude communities where ultraviolet radiation is more intense.
D)uniformly serious, with effects experienced in almost all ecosystems and trophic levels.

Question 7

When nitrogen is added to nitrogen-poor aquatic ecosystems, productivity _____ and the number of species _____.

A)increases; declines
B)increases; increases
C)declines; declines
D)declines; increases

Question 8

The organisms responsible for most of the conversion of atmospheric molecular nitrogen (N₂)to the nitrate or ammonium that can be used by most other organisms are

A)photosynthetic plants.
B)bacteria.
C)fungi.
D)mammals.

Question 9

Humans are particularly adept at water transformation; current estimates are that human activities have affected nearly _____ percent of the world's rivers.

A)10
B)40
C)70
D)100

Question 10

Humans now use approximately 30-35 percent of the terrestrial net primary productivity (NPP). A result of this is that

A)human hunger has been virtually eliminated.
B)the number of species on Earth has increased.
C)humans are often in direct competition with other species for food and other natural resources.
D)we have learned how to manage Earth's resources so that all species have the resources they need to survive.

Question 11

Which of the following represents the most significant anthropogenic modification to the nitrogen cycle?

A)industrial fixation of nitrogen to produce fertilizer
B)release of nitrogen dioxide as a waste emission from burning coal
C)production of nitrogen monoxide by car engines
D)nitrogen fixation by bacteria associated with agricultural crops such as peas

Question 12

Changes to the physical and biotic features of the Earth are called land and water transformations. Which of the following is an example of a water transformation?

A)Clearing land along an urban-growth boundary to allow a city to expand.
B)Constructing a dam along a river so that an expanding city may increase the availability of drinking water.
C)Clear-cutting a forest for the lumber needed to build the homes for an expanding city.
D)Clear-cutting a forest to make cropland to grow the food for an expanding city.

Question 13

Land and water transformations have many unintended consequences. One of the most serious is

A)the extinction of species.
B)continental drift.
C)the increasing concentrations of atmospheric ozone.
D)the reduction in global atmospheric carbon dioxide levels and the subsequent decline in worldwide NPP.

Question 14

Ample evidence now exists to show that worldwide environmental changes are occurring; one example is the

A)increased NPP observed within the world's aquatic ecosystems.
B)widespread occurrence of invasive species.
C)moderate decline in atmospheric carbon dioxide concentrations.
D)expansion of forested land as tree-replanting efforts become more accepted.

Question 15

Intentionally supplementing nitrogen into a monoculture like a cornfield has predictable and desirable results. Is the same true when added to a system as complex as a community?

A)Yes; both primary production and species diversity increase.
B)Yes; primary production decreases but species diversity increases.
C)No; both primary production and species diversity decrease.
D)No; primary production increases but species diversity decreases.

Question 16

About _____ percent of the human population lives near the coast. This makes the coasts _____.

A)50; vulnerable to disruption by humans
B)30; vulnerable to erosion by wave action
C)80; more stable due to foundations from buildings
D)20; more stable due to the addition of sand for recreational purposes

Question 17

In recent years, the amount of nitrogen compounds fixed by human activities has

A)exceeded the amount of nitrogen compounds fixed by natural processes.
B)been reduced to a level below the amounts fixed by natural processes.
C)equaled the amount fixed by natural processes.
D)fluctuated above and below the amounts fixed by natural processes.

Question 18

Converting atmospheric nitrogen into chemical forms that can be used biologically is called fixation. Which of the following organisms can fix nitrogen?

A)insects
B)oak trees
C)bacteria
D)fish

Question 19

Which of the following is a source of naturally occurring carbon dioxide in the atmosphere?

A)cellular respiration by living organisms
B)the combustion of plant material ignited by lightning
C)volcanic eruptions
D)all of the above

Question 20

Which of the following statements is not correct?

A)Land and water transformations are caused by humans.
B)Land and water transformations are global in scale.
C)Land and water transformations are currently occurring.
D)Land and water transformations have had little effect on Earth.

Question 21

Biodeisel fuel is produced from oils synthesized by and harvested from living plants. How does the use of biodeisel fuel compare to the use of fossil fuels with respect to the amount of carbon dioxide released to the atmosphere?

A)There is no difference; the combustion of the fuel produces carbon dioxide regardless of its source.
B)It is beneficial; converting plant material to biodeisel permanently traps carbon dioxide and prevents its entry to the atmosphere.
C)It is detrimental; because biodeisel produces lower mileage, more must be burned, causing a proportional increase in carbon dioxide release.
D)It is beneficial; because living plants are the source of the biodeisel, burning it simply represents nutrient recycling.

Question 22

Polar bears are threatened by a reduction in the amount of phytoplankton in the ocean because

A)polar bears are at the top of the food chain in which phytoplankton are the primary producers.
B)polar bears use phytoplankton as an important source of vitamins.
C)phytoplankton are bioindicators of the amount of ice in the polar bear's ecosystem.
D)polar bears become covered with phytoplankton as camouflage when they forage on the tundra.

Question 23

What best describes the relationship between cutting down forests and changes in atmospheric carbon dioxide levels?

A)Herbivore populations decline in the absence of forests, and without their respiration less carbon dioxide is recycled into the atmosphere.
B)The carbon dioxide used by the plants for cellular respiration would all be released into the atmosphere at once.
C)Trees naturally die and decompose, but when turned into lumber their carbon is prevented from recycling back to the atmosphere.
D)In the absence of forest plants, there would be less carbon dioxide removed from the atmosphere for use during photosynthesis.

Question 24

Having a sustainable impact on the Earth and our biosphere means that we must

A)produce more fertilizers to feed a growing population.
B)take advantage of global warming by growing more crops in areas that were previously unavailable for agriculture.
C)find ways to recycle carbon dioxide more rapidly.
D)create better balances between our consumption of resources and the rates at which they can be replenished.

Question 25

The single most significant human-caused contribution (about 75 percent)to the worldwide increase in atmospheric carbon dioxide is

A)acid rain and the subsequent chemical reactions that release carbon dioxide from the soil.
B)nitrogen supplements that accelerate decompositional activity and recycle carbon before it can become sequestered in the soil.
C)the burning of fossil fuels and the subsequent emission of carbon dioxide.
D)deforestation and the subsequent decline in photosynthesis.

Question 26

Atmospheric scientists anticipate a 3.5°C temperature rise in the next century; if so, what impacts will such change bring?

A)Some plant and animal species will migrate to cooler locations, whereas others will become extinct.
B)There will be a positive impact on the world's agricultural systems as ocean evaporation and terrestrial rainfall increase.
C)Sea levels could rise high enough to improve the ease of navigability and shipping.
D)The polar ice caps will increase in size.

Question 27

Carbon dioxide levels are increasing because

A)human agriculture has greatly increased the amount of carbon dioxide given off by plants during respiration.
B)humans have begun releasing carbon that was formerly sequestered in fossil fuels into the atmosphere.
C)holes in the ozone layer have reduced the total amount of photosynthesis occurring in the biosphere.
D)the huge growth in the human population and domestic livestock has increased the amount of carbon dioxide being released through respiration.

Question 28

Carbon dioxide makes up approximately _____ percent of Earth's atmosphere.

A)94
B)44
C)4
D)0.04

Question 29

In comparison to past estimates, extinction rates are currently high. Which of the following is the most plausible explanation?

A)Natural fluctuations in climate causes extinctions.
B)Continental drift is causing rapid changes in climate, which, in turn, causes extinctions.
C)Previous extinctions make survival of contemporary species more difficult.
D)Humans are affecting many aspects of the global environment.

Question 30

What characteristics would you expect to find in species that will most likely prosper as projected climate change occurs?

A)organisms with narrow tolerances that can live in specialized environments
B)organisms that have broad tolerances that can live in a variety of habitats
C)organisms that live in very stable environments
D)organisms that can live only if they form mutualistic relationships with other organisms

Question 31

The addition of carbon dioxide to the atmosphere also increases the amount of carbon dioxide dissolved in ocean water. This has the effect of

A)cooling the ocean water by increasing the rate of evaporation of ocean water.
B)warming the ocean water by decreasing the rate of evaporation of ocean water.
C)increasing the acidity of ocean water because dissolved carbon dioxide makes the water more acidic.
D)decreasing the acidity of ocean water because dissolved carbon dioxide makes the water less acidic.

Question 32

The physical and biotic changes humans make to the land surface of Earth are collectively known as land ____________________.

Question 33

The levels of carbon dioxide in the atmosphere

A)peaked around 1950 and have begun slowly decreasing since then.
B)are high but not higher than the highest estimated levels in the last 420,000 years.
C)are estimated to be higher than at any time in the past 420,000 years.
D)began decreasing when the use of CFCs stopped.

Question 34

Which of the following cycles appears to make the greatest contribution to climate change?

A)the phosphorus cycle
B)the carbon cycle
C)the sulfur cycle
D)the nitrogen cycle

Question 35

Historically, an unusual aspect of the recent rise in CO₂ levels is that

A)there is no known mechanism for its occurrence.
B)CO2 reacts so quickly with other compounds that it should not be occurring.
C)it has occurred relatively slowly.
D)it has occurred relatively rapidly.

Question 36

Which of the following would cause the slowest global change?

A)continental drift
B)climate change
C)human activity
D)volcanic activity

Question 37

When plants are initially exposed to elevated carbon dioxide levels most increase their rate of photosynthesis; how might plant communities be affected?

A)no changes other than increased NPP
B)competition increases for other resources such as sunlight or phosphorus with the eventual disappearance of some community members
C)community members decrease in size over time with the removal of the selection pressure for carbon dioxide acquisition
D)Because carbon dioxide is never a limiting factor like water, nitrogen, or phosphorus, increased levels typically have no significant effects.

Question 38

What will happen in the future if humans continue to impact natural systems at the same rates as today?

A)The environment is much too big and the human population much too small in comparison to have any serious consequences.
B)Human societies may experience severe disruptions in the services ecosystems provide that human societies depend on.
C)Some short-term changes may be experienced, but the magnitude will likely be no greater than those that have occurred naturally.
D)Some beneficial and necessary reductions on population growth will occur.

Question 39

Which of the following choices is a major difference between human-caused global change and that which occurs naturally?

A)Human-caused global change occurs more quickly, leaving organisms less time to adapt.
B)Human-caused global changes are of a smaller scale than naturally caused changes.
C)Naturally caused global change occurs only at one place on Earth at a time.
D)Naturally caused global changes are limited to the terrestrial habitats where humans live.

Question 40

Which of the following does not represent evidence for global warming?

A)The 10 hottest years on record have occurred since 1990.
B)In Europe, bird and butterfly species have shifted their ranges northward.
C)The hole in the ozone layer over Antarctica has been growing in size.
D)Plants in northern latitudes have increased the length of their growing seasons.

Question 41

The amount of nitrogen that cycles among organisms is ____________________ than the amount that is in the atmosphere.

Question 42

Long-lived synthetic organic molecules that bioaccumulate in organisms are referred to as ____________________.

Question 43

Humans are changing the way many chemicals ____________________ through ecosystems.

Question 44

Because wetlands have relatively little economic value, the percentage of the United States that is covered by wetlands has been relatively stable during the past 200 years.

Question 45

The highest concentrations of environmental pollutants are typically found in the predators at the top of the food web.

Question 46

Marine organisms with calcified structures, such as clams, are affected by increased atmospheric carbon dioxide levels because in the ocean these increases also cause an increase in ____________________.

Question 47

Wetlands are one of the few habitats to have escaped human-caused destruction; the worldwide distribution of wetlands has remained relatively stable for the past 200 years.

Question 48

Humans use approximately 15 percent of the world's total net primary production.

Question 49

When biologically usable nitrogen is increased in terrestrial communities, net primary productivity usually ____________________.

Question 50

Bisphenol A is found in plastic water bottles and has been shown to cause an increased risk of diabetes and reproductive problems among other disorders. Bisphenol A acts as a(n)____________________.

Question 51

Normally the major part of a polar bear's diet is composed of ____________________.

Question 52

Scientists predict that current increases in atmospheric carbon dioxide concentrations will cause temperatures on Earth to rise, a phenomenon known as ____________________.

Question 53

Using more "green" building materials, recycling more waste, using bicycles more, and reducing the use of fossil fuels are examples of ways that we can work toward ____________________.

Question 54

As a group, the ____________________ gases allow light energy to pass through the atmosphere but absorb heat energy as it passes through the atmosphere to outer space.

Question 55

Nitrogen gas makes up approximately 20 percent of the air we breathe.

Question 56

Humans have had little lasting impact on the physical appearance of Earth.

Question 57

All global changes presently observed on Earth are due to human activity.

Question 58

The cutting and burning of forests has led to an increase in global ____________________ levels.

Question 59

The conversion of N₂ to NH₄⁺ is called ____________________.

Question 60

The best hope for slowing the recent rapid ecological changes is to decrease the impact of ____________________ on Earth to a sustainable level.

Question 61

Global levels of carbon dioxide have risen dramatically in the past 200 years.

Question 62

The carbon that is increasing the levels of carbon dioxide in our atmosphere comes largely from fossil fuels.

Question 63

Ample evidence now exists that demonstrates that human activities are strongly associated with global warming.

Question 64

Human activities presently fix more nitrogen than all natural sources combined.

Question 65

The atmospheric concentration of carbon dioxide is presently approaching values equal to those believed to have existed 420,000 years ago.

Question 66

Net primary productivity is typically limited by the amount of nitrogen and phosphorus available to producers; when these nutrients are increased, NPP increases as well.

Question 67

Due to the reduction in pack ice-an effect of global warming-polar bears are eating more geese and goose eggs instead of seals.

Question 68

Even without the melting of polar ice, sea levels are anticipated to rise because warm water expands.

Question 69

Most plants can be considered carbon sinks; their net effect on atmospheric carbon is to reduce its concentration.

Question 70

The effects of global warming have already been detected in both aquatic and terrestrial ecosystems.