Deck 55: Population Ecology

Question 1

Which of the following statements about efforts to introduce large mammals to small isolated islands is true?

A) The populations never become established and invariably go extinct within a decade or two.
B) Such efforts always result in an initial population explosion, but then there is a crash.
C) Such efforts always succeed and result in the formation of stable populations.
D) Such efforts always result in populations with cyclical population dynamics.
E) None of the above

Answer 1

E

Question 2

The best way to reduce the population of an undesirable species in the long term is to

A) reduce the carrying capacity of the environment for the species.
B) selectively kill reproducing adults.
C) selectively kill prereproductive individuals.
D) attempt to kill individuals of all ages.
E) sterilize individuals.

Answer 2

E

Question 3

The dispersion pattern in which the presence of one individual increases the likelihood of another individual being nearby is

A) random.
B) regular.
C) clumped.
D) uniform.
E) irregular.

Answer 3

C

Question 4

For which of the following could population densities be estimated most easily?

A) Pine trees
B) Marsupials
C) Guppies
D) Squirrels
E) Chimpanzees

Question 5

Which of the following factors would be most conducive to conducting a full census of a population?

A) Small body size of the individuals in the population
B) Relatively stationary individuals
C) A large population
D) Both a and b
E) None of the above

Question 6

Density-dependent factors are population-regulating factors that

A) affect the same proportion of individuals regardless of population size.
B) are usually weather-related.
C) affect only sessile organisms.
D) influence only fecundity.
E) have effects that vary depending on population size.

Question 7

Populations that are most readily overharvested are characterized by having

A) very long-lived adults.
B) short prereproductive periods and many offspring.
C) short prereproductive periods and few offspring.
D) long prereproductive periods and few offspring.
E) long prereproductive periods and many offspring.

Question 8

The way in which the individuals in a population are spread over the environment describes that population's

A) dynamics.
B) regulation.
C) dispersion.
D) strategy.
E) survivorship.

Question 9

For which of the following populations would biologists most likely use number per unit of volume, rather than number per unit of area, in measuring population density?

A) Pine trees in a forest
B) Mice in a patch of grassland
C) Guppies in a lake
D) Squirrels on a campus
E) Oak seedlings in a backyard

Question 10

In northern forests and tundra, the primary nonhuman predators of large grazing mammals such as reindeer are

A) moose.
B) wolves.
C) bears.
D) lions.
E) elk.

Question 11

A group of individuals born at the same time is known as a

A) deme.
B) subpopulation.
C) Mendelian population.
D) cohort.
E) taxon.

Question 12

Which of the following is not an aspect of the study of demography?

A) The age structure of a population
B) A population's dispersion patterns
C) Population density
D) The genetic makeup of a population
E) Population dynamics

Question 13

If four hundred robins are found in a ten-hectare plot, the density of robins in that plot is _______ robin(s)/ha.

A) 1
B) 4
C) 40
D) 400
E) 4,000

Question 14

A metapopulation is

A) an unusually large population.
B) a population that is spread out over a very large area.
C) a group of subpopulations among which some individuals move occasionally.
D) a group of subpopulations that are isolated from one another.
E) a group of subpopulations among which individuals move on a regular basis.

Question 15

In a study of the population density of apple maggot flies, 150 flies are captured and marked in the first sample. Two days later, 300 flies are captured, 15 of which have marks. Based on these results, the estimated number of apple maggot flies in this population would be

A)300. B) 600.
C)1,500.
D)3,000.
E)6,000.

Question 16

The patterns and processes of changes in populations are called population

A) structure.
B) demography.
C) density.
D) dispersion.
E) dynamics.

Question 17

The process by which immigrants prevent a subpopulation from becoming extinct is called the

A) colonization effect.
B) rescue effect.
C) metapopulation effect.
D) genetic drift effect.
E) salvage effect.

Question 18

Which of the following is not a demographic event?

A) Growth
B) Birth
C) Death
D) Immigration
E) Emigration

Question 19

A population whose size levels off at its carrying capacity is exhibiting

A) exponential growth.
B) geometric growth.
C) logistic growth.
D) J-shaped growth.
E) negative growth.

Question 20

If a total of 2,400 oak trees are counted in a 6 km $\times$ 2 km rectangular patch of land, the density of the oak trees is _______ per square km.

A) 24
B) 48
C) 96
D) 120
E) 200

Question 21

If the intrinsic rate of growth of a population is zero, then the population

A) is extinct.
B) will soon be extinct.
C) is increasing in size.
D) is decreasing in size.
E) is stable in size.

Question 22

Which of the following types of survivorship curves best describes humans living in the contemporary United States?

A) Maturational
B) Ecological
C) Semelparous
D) Physiological
E) Logistic

Question 23

The number of offspring produced by a cohort is known as its

A) survivorship.
B) fertility.
C) fecundity.
D) life table.
E) None of the above

Question 24

Eighty-one pocket gophers were present in Maddox Field at the start of 2006. During that year, 24 individuals were born, and 19 died. Twelve individuals immigrated, and 10 emigrated. How many pocket gophers were present in Maddox Field at the start of 2007?

A) 76
B) 81
C) 86
D) 88
E) 146

Question 25

Which of the following represents the correct ranking of dispersal patterns, from the greatest to least expected difference between one individual and its nearest neighbor?

A) Random, clumped, regular
B) Random, regular, clumped
C) Regular, random, clumped
D) Regular, clumped, random
E) Clumped, regular, random

Question 26

Use the following to answer questions:
Suppose that of 300 mice in a mice colony born in January, 150 are still alive at the start of September, and 120 are still alive at the start of October.
What is the survivorship up to the start of September?

A) 0.15
B) 0.30
C) 0.45
D) 0.50
E) 0.60

Question 27

If a certain age interval in a population contains ten individuals and has a mortality rate of 1.00, how many individuals will be in the next older age interval?

A) 0
B) 1
C) 5
D) 9
E) 10

Question 28

Suppose seedlings of a plant emit a chemical that reduces the growth of other individuals around them. This would most likely result in the plants having a _______ dispersion pattern.

A) random
B) cohort
C) clumped
D) regular
E) logistic

Question 29

A biologist constructs a life table of a population of Thompson gazelles, but only studies the population for a brief period of time. Such a life table would have to be a(n) _______ life table.

A) cohort
B) horizontal
C) vertical
D) maturational
E) iteroparous

Question 30

In the Grants' 1978 study, the most important environmental factor affecting survival in cactus finches on Isla Daphne was discovered to be

A) rainfall.
B) temperature.
C) biotic factors.
D) predation.
E) None of the above

Question 31

Which of the following conditions would not bias the estimates made from a capture-mark-recapture study?

A) Movement of individuals away from the study site
B) Greater susceptibility of marked individuals to predation
C) Free intermingling of marked individuals with unmarked individuals
D) Marked individuals' preference for traps
E) None of the above

Question 32

Use the following to answer questions:
Suppose that of 300 mice in a mice colony born in January, 150 are still alive at the start of September, and 120 are still alive at the start of October.
If the survivorship at the start of November is 0.3, how many mice died during the month of November?

A) 10
B) 20
C) 30
D) 60
E) 90

Question 33

Use the following to answer questions:
Suppose that of 300 mice in a mice colony born in January, 150 are still alive at the start of September, and 120 are still alive at the start of October.
What is the mortality rate during the month of September?

A) 0.15
B) 0.20
C) 0.30
D) 0.50
E) 0.80

Question 34

Which pattern of survivorship is most likely for an organism such as the sea urchin, which produces large numbers of very small offspring and provides no parental care?

A) Most offspring survive for most of their potential life span and then die at the same time.
B) The probability of death is low throughout the life span.
C) Survivorship is high early in life and declines slowly.
D) Young individuals have a high probability of dying, but older individuals have a relatively low probability of dying.
E) The probability of death is equally high throughout the potential life span.

Question 35

Individuals of a population that are all born at the same time are known as a

A) survivorship.
B) cohort.
C) population structure.
D) demographic pool.
E) None of the above

Question 36

If the birth rate is 0.07 and the death rate is 0.14, then the intrinsic rate of increase (assuming that there is no immigration or emigration)

A) is negative.
B) is 0.07.
C) is 0.14.
D) is 0.21.
E) cannot be calculated.

Question 37

Which of the following best describes the demography of humans living in the contemporary United States?

A) Mortality rates decline rapidly in older individuals.
B) Survival rates remain relatively constant across all age groups once the individuals are a few months old.
C) Most individuals survive most of their potential life span.
D) High death rates of young individuals are followed by high survival rates during the middle part of the life span.
E) Survival rates vary considerably and reflect changes in rainfall.

Question 38

Which of the following statements about the intrinsic rate of increase is false?

A) It is symbolized as r.
B) It is equal to the birth rate minus the death rate (assuming no migration).
C) It is always positive (above zero).
D) It can be calculated from life tables.
E) All of the above are true; none is false.

Question 39

Which of the following statements about age structure is true?

A) All other factors being equal, populations with a large proportion of young individuals have a greater potential for population growth than those with a smaller proportion of young individuals.
B) All other factors being equal, populations with a large proportion of young individuals have a lesser potential for population growth than those with a smaller proportion of young individuals.
C) The proportion of the life cycle in which females are reproductively capable varies tremendously across different species.
D) Both a and c
E) Both b and c

Question 40

Which of the following would most likely be used to estimate the population density of a very large population of relatively stationary salamanders?

A) A full census
B) The mark-release method
C) A linear transect
D) Quadrats
E) None of the above

Question 41

Which of the following is not an assumption of the logistic growth equation?

A) An individual exerts its effects on resources immediately at birth.
B) All individuals produce equal effects.
C) Resources in the environment are limited.
D) Each individual depresses population growth equally.
E) There is a substantial time lag between gathering resources and reproduction.

Question 42

David Resnick's studies of guppies showed that

A) the most critical determinant of the life history strategy of guppies was the type of food they received.
B) the most critical determinant of the life history strategy of guppies was the concentration of calcium in the water.
C) predation selects for later reproduction in guppies.
D) predation selects for earlier reproduction in guppies.
E) None of the above

Question 43

The growth rate of a population in an unlimited environment

A) is described by an S-shaped curve.
B) is greater than the intrinsic rate of increase.
C) is equal to (b - d)N.
D) depends on competition for resources.
E) is infinite.

Question 44

Which of the following is an example of density-independent population regulation?

A) A contagious disease sweeps through a dense population of squirrels but leaves a less dense population relatively untouched.
B) Predators of lemmings search widely for places where lemmings are abundant and concentrate their hunting in those areas.
C) An outbreak of a moth species leads to a depletion of the food supply. As a result, the next generation of moths is underfed and produces few offspring.
D) When lemmings are abundant, arctic foxes switch from a primary diet of mice to a primary diet of lemmings.
E) An early cold spell kills 80 percent of the sparrows in a particular area.

Question 45

Pacific salmon grow, mate, and then reproduce once, a process known as spawning. Soon after they spawn, these fish die. These salmon are considered

A) K-strategists.
B) iteroparous.
C) semelparous.
D) examples of Bateman's principle.
E) examples of Zimmer's paradox.

Question 46

Which of the following statements about carrying capacity (K) is true?

A) When N = K, the birth rate in a population is necessarily zero.
B) The rate of population growth in an unlimited environment is proportional to K.
C) K is always determined by the amount of food in an environment.
D) In a population at its K, the birth rate equals the death rate.
E) None of the above

Question 47

If the birth rate is 0.05 and the death rate is 0.02, the intrinsic rate of increase (assuming that there is no immigration or emigration)

A) is 0.02.
B) is 0.03.
C) is 0.05.
D) is 0.07.
E) cannot be calculated.

Question 48

Which of the following would likely have the highest population densities?

A) Species A, which uses an abundant resource and has a large body size
B) Species B, which uses an abundant resource and has a small body size
C) Species C, which uses a scarce resource and has a large body size
D) Species D, which uses a scarce resource and has a small body size
E) Both a and c

Question 49

The logistic growth equation describes a population that

A) grows without limits.
B) grows rapidly at small population sizes, but whose growth rate slows and eventually stops as it reaches the number the environment can support.
C) rapidly overshoots the number the environment can support and then fluctuates around this number.
D) grows very rapidly and then crashes when environmental resources are depleted.
E) is declining in size.

Question 50

Which of the following species would most likely be iteroparous?

A) Social insects
B) Organisms that experience no large survival advantage as they approach adulthood
C) Annual plants
D) All of the above
E) None of the above

Question 51

Which of the following statements is an example of a density-independent effect?

A) The number of nests in an area is limited to 70.
B) The incidence of malaria increases as populations increase.
C) Drought kills seedlings.
D) Large aggregations of guppies attract predators.
E) None of the above

Question 52

We would expect populations to grow close to or at their intrinsic rate of growth when

A) they are near their environmental carrying capacity.
B) their numbers are low.
C) they have depleted their food supply.
D) density-dependent factors are reducing birth rates.
E) Both a and c

Question 53

Under ideal conditions, the birth rate per individual in a population of isopods is 0.12 offspring per day, and the death rate per individual is 0.04 offspring per day. If there are 7,000 individuals in the population, its biotic potential (per day) is

A)8.
B)28.
C)56.
D) 70
E)84.

Question 54

Which of the following attributes tends to promote stability in population numbers?

A) Long life span of individuals
B) Small size of the population
C) High reproductive rates
D) Dependence on a single resource
E) None of the above

Question 55

Which of the following is not typical of a K-strategy species?

A) Parental care
B) A long life span
C) Specialized use of resources
D) A small number of offspring
E) All of the above are typical of a K-strategy species.

Question 56

Which of the following statements about populations that follow logistic growth patterns is true?

A) When population sizes are small, their patterns of growth are similar to their exponential growth.
B) Their rate of growth is fastest when they are near their carrying capacity.
C) They are not subject to density-dependent factors.
D) All of the above
E) None of the above

Question 57

Assume that a population of aphids follows the logistic equation for population growth. If the carrying capacity is 2,000 and the intrinsic rate of growth is 0.1 per day, at what population size will the rate of population growth be 0.05?

A) 1,000
B) 1,500
C) 2,000
D) 3,000
E) 20,000

Question 58

The intrinsic rate of increase (r) is the

A) number of individuals added to each generation in a growing population under optimal conditions.
B) difference, under optimal conditions, between the average per capita birth rate (b) and the average per capita death rate (d).
C) number of individuals added to each generation in a growing population under actually occurring conditions.
D) average per capita birth rate (b) under optimal conditions.
E) difference, under actually occurring conditions, between the average per capita birth rate (b) and the average per capita death rate (d).

Question 59

Which of the following statements about the biotic potential of a population is true?

A) It is equal to the product of the intrinsic rate of population growth times the carrying capacity.
B) It is equal to the product of the intrinsic rate of population growth times the population size.
C) Populations can grow at rates close to their biotic potential essentially indefinitely.
D) Both a and c
E) Both b and c

Question 60

An r-strategy species typically does not

A) have semelparous reproduction.
B) tolerate a wide range of resource conditions.
C) provide parental care.
D) have a high intrinsic rate of increase.
E) produce large numbers of offspring.

Question 61

Which of the following could be the age in 2010 of someone born during the post-WWII baby boom in the United States?

A) 2
B) 22
C) 42
D) 62
E) 82

Question 62

Which of the following statements about the cane toad is true?

A) It has been able to control the populations of cane beetles in Australia.
B) It has become a pest in Australia.
C) It is not poisonous-that belief is a myth.
D) Both a and b
E) Both b and c

Question 63

For mobile organisms, the population density can be estimated by use of the _______ method, which involves the capturing and tagging of individuals.

Question 64

A population of water fleas in one pond has been declining. A storm leads to the migration of a few individuals from another pond into the original subpopulation, and the new migrants help prevent the original population from going extinct. This is an example of

A) environmental carrying capacity.
B) compensation.
C) the rescue effect.
D) density-independent factors.
E) habitat selection.

Question 65

Sustainable management of whale populations is generally more difficult than that of fish populations because

A) whales reproduce at much lower rates than fish do.
B) the whale population has had a baby boom echo.
C) whales are distributed widely throughout the oceans of the world.
D) unlike fish, whales do not undergo the rescue effect.
E) whales are r-strategists.

Question 66

Births, deaths, and patterns of migration are all considered _______ events.

Question 67

Geographically distant events would likely have the most impact on populations of

A) cedar trees.
B) migratory birds.
C) pine trees.
D) sedentary beetles.
E) minnows living in small isolated ponds.

Question 68

Which of the following would likely lead to a large population density of a species?

A) Use of an abundant resource
B) Large body size
C) Complex social organization
D) Both a and b
E) Both a and c

Question 69

Which of the following would be unlikely to contribute to large fluctuations in population size?

A) Frequent environmental disturbance
B) A high death rate
C) A density-dependent birth rate
D) A high birth rate
E) Seasonal variation in temperature

Question 70

The population density is the number of individuals in the population _______ by the area of the space covered by the population.

Question 71

Intensive fishing of the rockfish led to the evolution of _______ fish because _______ fish were selectively caught.

A) larger; smaller
B) larger; larger
C) smaller; larger
D) smaller; smaller
E) more oily; more oily

Question 72

Approximately how long did it take the human population to grow from 1 billion to 7 billion?

A) Between 100 and 200 years
B) Between 200 and 300 years
C) Between 300 and 500 years
D) Between 500 and 1,000 years
E) More than 1,000 years

Question 73

The larger population that comprises many subpopulations is known as a

A) habitat patch.
B) metapopulation.
C) megapopulation.
D) population structure.
E) None of the above

Question 74

Which of the following was a conclusion drawn from experiments involving the manipulation of habitat patches of springtails that live on moss?

A) Large populations are more vulnerable to extinction than small populations.
B) Even small barriers to recolonization raise extinction rates of subpopulations.
C) Corridors between patches of habitat increase extinction rates.
D) All of the above
E) None of the above

Question 75

Which of the following factors would make it more likely that an animal species could survive despite being harvested at a high rate?

A) A low reproductive capacity
B) Density-dependent growth rates of individuals
C) A long maturation period for individuals of the species
D) All of above
E) None of the above

Question 76

Which of the following statements about biological control is false?

A) Natural enemies employed in biological control against invasive species are often taken from the native range of the pest species.
B) Biological control can use predators as natural enemies.
C) Biological control can use pathogens as natural enemies.
D) Agents used in biological control occasionally become pests themselves.
E) All of the above are true; none is false.

Question 77

Suppose that in a species of beetle, close proximity to another individual of the same species enhances survival. This phenomenon would likely lead to a _______ dispersion pattern for the species.

Question 78

A group of individuals all born in the same time period constitutes a _______.

Question 79

Zebra mussels, which do not reach high densities in Europe, are a major pest in North America because they are

A) native to North America.
B) less subject to predation and pathogens in North America than in Europe.
C) not a food delicacy, as they are in Europe.
D) All of the above
E) None of the above

Question 80

Which of the following is most consistent with a species with an r life-history strategy?

A) Long maturation time
B) Large body size
C) Choice of strong mates
D) Density-dependent mortality
E) A maturational survivorship curve