Deck 40: Population Ecology and the Distribution of Organisms

Question 1

In which of the following terrestrial biome pairs are both biomes dependent upon periodic burning?

A)tundra and coniferous forest
B)chaparral and savanna
C)desert and savanna
D)tropical and broadleaf forest
E)grassland and tundra

Answer 1

B

Question 2

Which of the following levels of ecological organization is arranged in the correct sequence from most to least inclusive?

A)community,ecosystem,individual,population
B)ecosystem,community,population,individual
C)population,ecosystem,individual,community
D)individual,population,community,ecosystem
E)individual,community,population,ecosystem

Answer 2

B

Question 3

Deserts typically occur in a band around 30 degrees north and 30 degrees south latitude because

A)descending air masses originating from the tropical areas tend to be dry.
B)ascending air masses absorb moisture and create an arid,desert climate.
C)moisture-laden air is heavier than dry air and is not carried to these latitudes.
D)these locations get the most intense solar radiation of any location on Earth.

Answer 3

A

Question 4

A cosmic catastrophic event occurred that caused the tilt of the Earth's axis relative to its plane of orbit to increase from 23.5 degrees to 90 degrees.The most obvious effect of this change would be

A)the elimination of trade winds.
B)an increase in the length of night.
C)an increase in the length of a year.
D)the elimination of seasonal variation.

Question 5

Which of the following choices causes all of the others in creating global terrestrial climates?

A)differential heating of Earth's surface
B)Pacific and Atlantic ocean currents
C)seasonal changes in wind patterns
D)evaporation of water from the oceans

Question 6

Which of the following statements best describes the effect of climate on biome distribution?

A)Average annual temperature and precipitation are sufficient to predict which biome will be found in a certain area.
B)Seasonal climate variation is not a limiting factor in biome distribution in areas with the same annual climate patterns.
C)Both average climate and the pattern of climatic variation are important in determining the nature of an area biome.
D)Temperate forests and grasslands are not the same biomes solely because of the variances in sunlight received.
E)Correlation of climate with biome distribution is sufficient to determine the cause of terrestrial biome patterns.

Question 7

The tilt of the Earth's axis relative to its plane of orbit is 23.5 degrees.Which of the following events might you predict to occur if the angle of tilt increased to 33 1/2 degrees?

A)Summers in the United States would likely become warmer.
B)Winters and summers in Australia would become indiscrete.
C)Seasonal variation at the equator might decrease significantly.
D)The North and South poles would experience massive ice melts.

Question 8

In mountainous areas of western North America,which type of plant life would you expect to find on a southern-slope of a mountain?

A)drought-tolerant plants
B)coniferous pine trees
C)broadleaf woody trees
D)cone-bearing trees

Question 9

Palm trees and subtropical plants are commonplace in Land's End,England,whose latitude is the equivalent of Labrador in coastal Canada,where the local flora is subarctic.Which of the following contributes the most to the differences between these two biomes?

A)differences in latitude
B)direction of ocean currents
C)variances in annual rainfall
D)intensity of solar radiation

Question 10

Generalized global air circulation and precipitation patterns are dependent on the intensity of solar radiation near the equator.Which of the following correctly states an event that contributes to the creation of these global patterns?

A)rising,warm,moist air masses at 30 degrees north and south
B)rising air masses that expand and cool in the tropical regions
C)rising cool,moist air masses at 90 degrees north and south
D)rising air masses that expand and warm in temperate regions

Question 11

A particular mountain range is subjected to prevailing winds.Which of the following contributes the most to a drier climate on the leeward side of the mountain range?

A)air expanding and heating on the windward side of the range
B)air expanding and cooling on the windward side of the range
C)air expanding and heating on the leeward side of the range
D)air expanding and cooling on the leeward side of the range

Question 12

With respect to the sun,Earth normally rotates once in a 24-hour period.What would be the effect on climate in the temperate latitudes if the rotation increased to 48-hours?

A)Seasons would be longer and more distinct;for example,colder winters and hotter summers.
B)Smaller ranges between nighttime low and daytime high temperatures would be common.
C)Large-scale weather events such as hurricanes would no longer be a part of regional climates.
D)In the Northern and Southern hemispheres,winter precipitation would increase in frequency.
E)Larger ranges between daytime high and nighttime low temperatures would occur frequently.

Question 13

Air masses formed over the Pacific Ocean eventually encounter extensive north-south mountain ranges as they move from west to east.Which statement best describes a component of an outcome of this encounter between a mountain range and an air mass?

A)The cool,moist Pacific air heats up as it rises,releasing its precipitation as it passes the tops of the mountains.
B)The warm,moist Pacific air rises and cools,releasing precipitation as it moves up the windward 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.
D)The warm,moist Pacific air is blocked by the mountains,resulting in the heavy annual rainfall on the windward side.
E)These air masses remain essentially unchanged in moisture content and temperature as they pass over the ranges.

Question 14

Fire suppression by humans

A)will always result in an increase in species diversity in a given biome.
B)can change the species composition within biological communities.
C)will result in more small non-woody plants and fewer trees in savannas.
D)is necessary to maintain species composition in grassland and chaparral.

Question 15

The main reason that polar regions are cooler than the equator is that

A)there is more ice/glaciers at polar regions.
B)sunlight strikes the poles at a lower angle.
C)the polar regions are farther from the sun.
D)the polar regions' atmosphere is thinner.
E)the poles are always tilted away from the sun.

Question 16

What is the limiting factor for the growth of trees in the tundra?

A)low precipitation
B)lack of sunlight
C)insufficient minerals in bedrock
D)pH of soils
E)permafrost

Question 17

Trees are rare in the savanna biome because of

A)tropical storms.
B)acidic topsoils.
C)frequent fires.
D)limited rainfall.

Question 18

Coral reefs can be found 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)sunlight intensity
B)ocean salinity
C)day length
D)ocean currents
E)precipitation

Question 19

Areas where terrestrial biomes grade into neighboring biomes way be wide or narrow.Which of the following terms best describes this intergradation?

A)latitude
B)ecotone
C)longitude
D)ecosystem

Question 20

The growing season would generally be shortest in which of the following biomes?

A)an African savanna
B)a broadleaf forest
C)a temperate grassland
D)a tropical rain forest
E)a Northern pine forest

Question 21

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)investigate the various biotic and abiotic factors that are unique to high altitude.
C)conduct soil analysis for growth supporting chemicals in the vicinity of these trees.
D)collect data on temperature,wind,and rainfall at several of these locations for a year.

Question 22

Which of the following would most likely promote random distribution?

A)territorial species well-rooted in an area
B)periodic use of chemical attractants
C)flocking and schooling behaviors
D)spacing during the breeding season
E)constancy of key chemical factors

Question 23

Which of the following methods would provide the most legitimate data on population density?

A)Count the number of nests of a particular species of songbird,and multiply this by two (because there are two parent birds per nest).
B)Count the number of pine trees in several randomly selected 10-m × 10-m plots,and extrapolate this number to the fraction of the study area that these plots represent.
C)Calculate the difference between all of the immigrants and emigrants to see if the population is growing or shrinking.
D)Add the number of births and subtract the number of individuals who die to see if the population's density is increasing or decreasing.

Question 24

An ecologist recorded 12 white-tailed deer per one square mile in one woodlot and 20 per one square mile in another woodlot.What was the ecologist comparing?

A)density
B)dispersion
C)capacity
D)cohorts
E)range

Question 25

If a meteor impact or volcanic eruption injected a lot of dust into the atmosphere and reduced the sunlight reaching Earth's surface by 70% for one year,which of the following marine communities most likely would be least affected?

A)deep-sea vent
B)coral reef
C)intertidal
D)pelagic
E)estuary

Question 26

Long-term studies of Belding's ground squirrels show that immigrants move nearly 2 km from where they are born and become 1-8% of the males and 0.7-6% of the females in other populations.On an evolutionary scale,why is this significant?

A)These immigrants make up for the deaths of individuals,keeping the other populations' sizes stable over time.
B)Young reproductive males tend to stay in their home population and are not driven out by other territorial males.
C)These immigrants provide a source of genetic diversity for the newly formed squirrel populations.
D)Those individuals that emigrate to these new populations are looking for less crowded conditions with more resources.
E)The populations of ground squirrels will move from a clumped to a uniform population pattern of dispersion.

Question 27

Which of the following examples of an ecological effect leading to an evolutionary effect is most correct?

A)When seeds are not plentiful,trees produce more seeds which can germinate when conditions improve.
B)A few organisms of a larger population survive a drought,and then these survivors emigrate to less arid environments.
C)Only animals with denser fur survived the coldest days of an ice age,and all the future offspring have dense fur.
D)Fish that swim the fastest in running water catch the most prey and more easily escape predation.

Question 28

Which of the following is a physical factor that can limit the geographic distribution of species?

A)predation
B)disease
C)soil structure
D)nutrients
E)pH

Question 29

To construct a life table for a sexual species,you need to

A)assess sperm viability for the males in the population.
B)keep track of all the offspring of a cohort.
C)keep track of the female individuals in a cohort.
D)keep track of all the offspring of females in a cohort.

Question 30

Which of the following is the best natural example of uniform distribution?

A)bumblebees collecting pollen in a wildflower meadow
B)snails in an intertidal zone at low tide in California
C)territorial songbirds in a mature forest during mating season
D)mushrooms growing on the floor of an old-growth forest
E)a cultivated sweet cornfield in an urban community

Question 31

Which marine zone is expected to have the lowest rates of primary productivity (photosynthesis)?

A)pelagic
B)abyssal
C)photic
D)limnetic
E)intertidal

Question 32

Which of the following sets of measurements would best describe a population's physical structure and vital statistics?

A)density,dispersion,and demographics
B)gene frequency over time a year
C)annual precipitation averages
D)annual temperature extremes
E)ratio of predators to prey in an area

Question 33

A population is correctly defined as having which of the following characteristics?
I)inhabits the same general area
II)belongs to the same species
III)possesses a constant and uniform density and dispersion

A)I only
B)III only
C)I and II only
D)II and III only
E)I,II,and III

Question 34

Which of the following statements best describes the interaction between fire and ecosystems?

A)Fires maintain the low,widely scattered vegetation found in deserts.
B)Many kinds of plants and plant communities have adapted to frequent fires.
C)Many species in temperate broadleaf forests depend on fire to regenerate.
D)Chaparral communities have evolved to the extent that they rarely burn.
E)Most species have not adapted to fire as it is unnatural in every ecosystem.

Question 35

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

Question 36

Which of the following methods would most accurately measure the density of the population being studied?

A)counting the number of prairie dog burrows per square mile
B)counting the number of coyote droppings per square meter
C)counting the number of moss plants in one square kilometer
D)counting the number of zebras from airplane observations

Question 37

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 of organisms.
D)determine if dispersal limited distribution of organisms.
E)consolidate a landscape region into a single ecosystem.

Question 38

Uniform spacing patterns in plants such as the creosote bush are most often associated with

A)chance.
B)patterns of high humidity.
C)the random distribution of seeds.
D)the concentration of nutrients within the population's range.
E)competitive interaction between individuals of the same population.

Question 39

Which statement best describes how climate might change if Earth were 75% land and 25% water?

A)Terrestrial ecosystems would likely experience increased precipitation.
B)Daytime temperatures would be higher and nighttime temperatures lower.
C)Summers would be longer and winters shorter for locations at midlatitude.
D)Earth would experience an increase in temperate broadleaf forest regions.
E)Terrestrial microclimates would increase because of fluctuations in climate.

Question 40

Which of the following groups would be most likely to exhibit uniform dispersion?

A)red squirrels,a type of animal that actively defends its territories
B)cattails,plants that grow primarily at edges of lakes and streams
C)dwarf mistletoes,plants that parasitize particular species of forest trees
D)moths in cities throughout North America that are active at night
E)lake trout,fish that seek out cold,deep water high in dissolved oxygen

Question 41

What is population dispersion?

A)the number of individuals in a population per unit area or volume
B)the pattern of spacing among individuals within a population's boundaries
C)the influx of new individuals from other areas through immigration
D)the defense of a bounded physical space against encroachment by others

Question 42

In July 2008,the U.S.population was approximately 302,000,000.If the estimated 2008 growth rate was 0.88%,approximately how many total Americans were there in July 2009?

A)2,700,000
B)5,500,000
C)303,000,000
D)304,700,000
E)2,710,800,000

Question 43

Carrying capacity is

A)seldom exceeded in most real populations as resources are always abundant.
B)the maximum population size that any one particular environment can support.
C)fixed for almost all species over most of their range the majority of the time.
D)determined by density and dispersion data obtained through population studies.
E)the term used to describe the stress a population undergoes due to limited resources.

Question 44

Often the growth cycle of one population has an effect on the cycle of another.As moose populations increase,for example,wolf populations also increase.Thus,if we are considering the logistic equation for the wolf population,dN/dt = rN ,which factor accounts for the effect of the moose population?

A)r
B)N
C)rN
D)K
E)dt

Question 45

A population of ground squirrels has an annual per capita birth rate of 0.06 and an annual per capita death rate of 0.02.Calculate an estimate of the number of individuals added to (or lost from)a population of 1,000 individuals in one year.

A)120 individuals added
B)40 individuals added
C)20 individuals added
D)400 individuals added
E)20 individuals lost

Question 46

Starting from a single individual,what is the size of a population of bacteria that reproduce by binary fission every 20 minutes at the end of a 2-hour time period? (Assume unlimited resources and no mortality. )

A)8
B)16
C)32
D)64
E)128

Question 47

Natural selection involves energetic trade-offs between

A)choosing how many offspring to produce over the course of a lifetime and how long to live.
B)producing larger numbers of gametes with internal fertilization versus external fertilization.
C)increasing the quantity of offspring per reproductive episode and an increase in parental care.
D)ensuring high offspring survival rates per reproductive episode and the cost of parental care.

Question 48

In models of logistic population growth,

A)the population growth rate slows,eventually becoming zero as N approaches K.
B)new individuals are added to the population most rapidly as K approaches N.
C)new individuals are added to the population most rapidly as N approaches K.
D)only density-independent environmental factors affect the rate of population growth.
E)carrying capacity is the number of additional individuals the environment can support.

Question 49

In 2008,the New Zealand population was approximately 4,275,000.If the birth rate was 14 births for every 1,000 people,approximately how many births occurred in New Zealand in 2008?

A)6,000
B)42,275
C)60,000
D)140,000
E)600,000

Question 50

The three basic variables that make up the life history of an organism are

A)life expectancy of females in the population,birth rate of offspring,and death rate of offspring.
B)number of reproductive females in the population,age structure of the population,and life expectancy.
C)age when reproduction begins,how often reproduction occurs,and how many offspring are produced per reproductive episode.
D)how often reproduction occurs,life expectancy of females in the population,and number of offspring per reproductive episode.
E)the number of reproductive females in the population,how often reproduction occurs,and death rate.

Question 51

Which of the following best defines a cohort?

A)a group of individuals that inhabits a small isolated region within the range for the species
B)all of the individuals that are annually added to a population by birth and immigration
C)the reproductive males and females within the population that can produce offspring
D)a group of individuals from the same age group,from birth until they are all dead
E)the number of individuals that annually die or emigrate out of a population

Question 52

As N approaches K for a certain population,which of the following is predicted by the logistic equation?

A)The population growth rate will not change.
B)The population growth rate will approach zero.
C)The population will increase exponentially.
D)The carrying capacity of the environment will increase.

Question 53

Using the logistic growth model,population growth would be represented by dN/dt =

A) .
B)rN.
C)rN (K + N).
D)rN .
E)rN .

Question 54

Which of the following describes a Type II survivorship curve?

A)flat at the start,then dropping steeply as death rates increase
B)dropping sharply at the start,then flattening out as death rates decline
C)a constant decline with a constant death rate over the life span
D)flat at the start,then rising steeply as death rates decrease

Question 55

Why do some invertebrates,such as lobsters,show a "stair-step" survivorship curve?

A)Many invertebrate species mate and produce offspring on multiyear cycles.
B)Younger individual species have a higher survivorship than older individuals.
C)Invertebrates are vulnerable to predation during molting when their shell is soft.
D)Some species have fluctuating population cycles according to the frequency of sunspots.
E)The number of fertilized eggs that mature to adult females depends on ambient temperature.

Question 56

Which of the following models is used to examine decreases in the rate of population growth as population size approaches carrying capacity?

A)exponential growth
B)logistic growth model
C)survivorship curve
D)intrinsic rate of increase

Question 57

What is an assumption of the logistic model of population growth?

A)Populations adjust instantaneously to growth.
B)Populations reach carrying capacity abruptly.
C)There is no limitation to growth exhibited.
D)Growth depends on predators and competitors.

Question 58

Consider two forests: one is an undisturbed old-growth forest,and the other has recently been logged.In which forest are species likely to experience exponential growth,and why?

A)old growth,because the stable conditions would favor exponential growth of all species in the forest
B)old growth,because each of the species is well established and can produce many offspring
C)logged,because the disturbed forest affords more resources for increased specific populations to grow
D)equally probable in old-growth and logged forests,because disturbed and stable habitats have equal opportunity for tree seedlings to survive

Question 59

Exponential growth of a population is represented by dN/dt = rN.What does "r" represent in the equation?

A)extrinsic rate of increase
B)intrinsic rate of increase
C)extrinsic rate of decrease
D)intrinsic rate of decrease

Question 60

Which of the following causes populations to shift most quickly from an exponential to a logistic population growth?

A)increased birth rate
B)removal of predators
C)decreased death rate
D)competition for resources
E)favorable climatic conditions

Question 61

What is one application of the metapopulation concept?

A)It models conservation as multiple species live in a network of habitat patches.
B)It shows how many different populations can coexist within one community.
C)It predicts the carrying capacity of populations that exhibit limited growth rates.
D)It explains why some high density populations have a clumped dispersion pattern.

Question 62

Figure 40.2 shows a generalized cross section of the marine environment with various zones labeled with letters.Choose the number that best answers the question(s).
Figure 40.2
Which zone has a condition of constant temperature?

A)1
B)2
C)3
D)4
E)5

Question 63

Which of the following best substantiates why location 3 is an equatorial (tropical)climate?

A)It has a monsoon season during the winter months.
B)It has consistent monthly averages for rainfall.
C)The temperature is high for each monthly average.
D)The temperatures reach 100°F during some months.
E)The temperatures are lower in June,July,and August.

Question 64

Which of the following is most likely to contribute to density-dependent regulation of populations?

A)yeast converting ethanol to carbohydrates
B)intraspecific competition for nutrients
C)lack of chemical territorial boundaries
D)extrinsic factors regulating reproduction

Question 65

Figure 40.2 shows a generalized cross section of the marine environment with various zones labeled with letters.Choose the number that best answers the question(s).
Figure 40.2
Which zone has the lowest biomass per unit of volume?

A)1
B)2
C)3
D)4
E)5

Question 66

Which variables define the ecological life history of a species?

A)the age at which reproduction begins,frequency of reproduction,and the number of offspring for each reproductive episode
B)the ratio of females to males,the length of the breeding season,and the number of offspring for each reproductive episode
C)the number of offspring produced over a lifetime by a breeding pair and the survivability of the offspring
D)timing breeding sessions with optimal environmental conditions and the number of offspring produced during each breeding session
E)the amount of parental care given after birth,the number of reproductive episodes per year,and the number of years females are capable of producing viable offspring

Question 67

Please use the following information to answer the question(s)below.
The eight climographs in Figure 40.1 show yearly temperature (line graph and left vertical axis)and precipitation (bar graph and right vertical axis)averages for each month for some locations on Earth.Choose the climograph that best answers the question.
Figure 40.1
Which climograph shows the climate for location 1?

A)I
B)III
C)V
D)VII
E)VIII

Question 68

Which of the following could be a density-independent factor limiting human population growth?

A)housing units
B)earthquakes
C)plagues
D)famines

Question 69

Which climograph shows the climate for location 2?

A)II
B)III
C)IV
D)VI
E)VIII

Question 70

Which of the following reproductive strategies is consistent with energetic trade-off and reproductive success?

A)Pioneer species of plants produce many very small,highly airborne seeds.
B)Rabbits that suffer high predation rates produce several litters per breeding season.
C)Animals that are caring parents produce fewer offspring with lower infant mortality.
D)A flowering plant nurtures its thousands of seeds until they are ready to germinate.

Question 71

Which climograph shows the climate for location 3?

A)II
B)III
C)IV
D)V
E)VI

Question 72

Which of the following is an expected characteristic of K-selected populations?

A)offspring born with good chances of survival
B)small offspring born in crowded environments
C)a high intrinsic rate of population increase
D)early parental reproduction in populations

Question 73

Which of the following is an intrinsic physiological factor that can regulate population size?

A)transmission rate of a disease in a dense area
B)competition for nutrients within territories
C)flooding of a flood plain by an adjacent river
D)hormonal changes in response to aggression

Question 74

In which of the following situations would you expect to find the largest number of K-selected individuals?

A)a recently abandoned farm field
B)a shifting sand dune community
C)an old-growth (virgin)forest
D)a coastline after a hurricane
E)a newly emergent volcanic island

Question 75

Which climograph shows the climate for location 5?

A)I
B)III
C)IV
D)V
E)VIII

Question 76

Why do populations grow more slowly as they approach their carrying capacity?

A)Density-dependent factors lead to fewer births and increased mortality.
B)Density-independent factors lead to fewer births and increased mortality.
C)Hormonal changes promote higher death rates in crowded populations.
D)Individuals voluntarily stop mating so that overcrowding does not occur.
E)The incoming energy decreases in populations experiencing a high rate of increase.

Question 77

What is a metapopulation?

A)all of the populations of different species within a community
B)family units and their patches within a single population
C)populations that are linked by immigration and emigration
D)the exponential growth in a population's numbers over time

Question 78

Figure 40.3
In Figure 40.3,which curve best describes survivorship in marine molluscs?

A)A
B)B
C)C
D)D
E)E

Question 79

Which climograph shows the climate for location 4?

A)I
B)II
C)III
D)V
E)VI

Question 80

Figure 40.2 shows a generalized cross section of the marine environment with various zones labeled with letters.Choose the number that best answers the question(s).
Figure 40.2
Which zone produces the most global oxygen?

A)1
B)2
C)3
D)4
E)5