Population Ecology

Growth of a population in an ideal, unlimited environment, represented by a J-shaped curve when population size is plotted over time, is known as a. exponential population growth b. logistic population growth c. unlimited population growth d. reproductive population growth

a. exponential population growth

The movement of individuals out of a population is known as a. emigration b. immigration c. death d. population flow

a. emigration

The aggregate of land and water area required by a person, city, or nation to produce all of the resources it consumes and to absorb all of the waste it generates is known as the a. ecological footprint b. carbon footprint c. land management footprint d. resource footprint

a. ecological footprint

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.

a. Density-dependent factors lead to fewer births and increased mortality.

Which of the following is most likely a density-dependent growth regulator of animal populations? a. a decrease in clutch size b. hurricanes c. fires d. droughts e. All of the listed responses are correct.

a. a decrease in clutch size

A group of individuals of the same species that live in the same area and interbreed, producing fertile offspring, is known as a. a population b. a community c. an ecosystem d. a meta-population

a. a population

A population that grows rapidly at first and then levels off at carrying capacity can be modeled _____. a. by a logistic equation b. as dN/dt = b - d c. as an opportunistic species d. as dN/dt = rN e. as being relatively unaffected by limiting factors

a. by a logistic equation

The ____________ is the maximum population size that can be supported by the available resources, symbolized as K. a. carrying capacity b. exponential size c. logistic size d. ideal size

a. carrying capacity

An ecologist would suspect a population to be growing rapidly if it _____. a. contains many more pre-reproductive than reproductive individuals b. is near its carrying capacity c. is limited only by density-dependent factors d. shows a clumped pattern of dispersion e. is far below its carrying capacity

a. contains many more pre-reproductive than reproductive individuals

The study of changes over time in the vital statistics of populations, especially birth rates and death rates, is known as a. demography b. birth-death analyses c. mortality studies d. ecology

a. demography

An ecologist recorded 12 white-tailed deer, Odocoileus virginianus, per square mile in one woodlot and 20 per square mile in another woodlot. What was the ecologist comparing? a. density b. dispersion c. carrying capacity d. cohorts e. range

a. density

__________ refers to the number of individuals per unit area or volume. a. density b. population c. clump d. dispersal area

a. density

______________ refers to any characteristic that varies with population density. a. density dependent b. density independent c. dispersal d. clumped

a. density dependent

_______________ refers to any characteristic that is not affected by population density. a. density independent b. density dependent c. symtropic d. allotropic

a. density independent

The pattern of spacing among individuals within the boundaries of a population is known as a. dispersion b. immigration c. emigration d. migration

a. dispersion

The logistic growth model differs from the exponential growth model in that it _____. a. expresses the effects of population-limiting factors on exponential growth b. is J-shaped and the exponential growth model is S-shaped c. never shows the effects of population-limiting factors d. implies that population size stabilizes at K when the birth rate is zero e. implies that a population's growth rate will be highest when the population is small

a. expresses the effects of population-limiting factors on exponential growth

Assuming that r has a positive value, in the formula dN/dt = rmaxN(K - N)/K, the factor rN tends to cause the population to _____. a. grow increasingly rapidly b. remain stable at the carrying capacity c. decrease in size d. grow at a slower rate than the (K - N/K) factor e. None of the listed responses is correct.

a. grow increasingly rapidly

The influx of new individuals into a population from other areas is known as a. immigration b. emigration c. population flow d. clumping

a. immigration

Population growth that levels off as population size approaches carrying capacity is known as a. logistic population growth b. exponential population growth c. controlled population growth d. regulated population growth

a. logistic population growth

A population's carrying capacity a. may change as environmental conditions change. b. can be accurately calculated using the logistic growth model. c. generally remains constant over time. d. increases as the per capita growth rate (r) decreases. e. can never be exceeded.

a. may change as environmental conditions change.

Which of the following groups would be most likely to exhibit uniform dispersion? a. red squirrels, who actively defend territories b. cattails, which grow primarily at edges of lakes and streams c. dwarf mistletoes, which parasitize particular species of forest tree d. moths, in a city at night

a. red squirrels, who actively defend territories

______________ is a behavior in which an animal defends a bounded physical space against encroachment by other individuals, usually of its own species. a. territoriality b. aggression c. non-cooperation d. cooperation

a. territoriality

In models of logistic population growth, a. the population growth rate slows dramatically as N approaches K. b. new individuals are added to the population most rapidly at the beginning of the population's growth. c. new individuals are added to the population as N approaches K. d. only density-dependent factors affect the rate of population growth. e. carrying capacity is never reached.

a. the population growth rate slows dramatically as N approaches K.

To calculate the human population density of your community, you would need to know the number of people living there and _____. a. the size of the area in which they live b. the birth rate of the population c. whether population growth is logistic or exponential d. the dispersion pattern of the population e. the carrying capacity

a. the size of the area in which they live

Herring gulls fiercely defend the areas around their nests in cliff-top breeding colonies. Within the colony they would show a _____ dispersion pattern. a. uniform b. random c. dense d. density-independent e. clumped

a. uniform

_________________ is a period of stability in population size, when additions to populations through births and immigration are balanced by subtractions through death and emigration. a. zero population growth b. logistic growth c. exponential growth d. birth-death balance

a. zero population growth

Which choice below is an example of an expression of population density? a. 255 dogfish sharks b. 100 sea stars, barnacles, and mussels per 25 m2 of a tide pool c. the number of Paramecium caudatum in a 250-mL solution in a glass flask d. the total number of sturgeon per cubic meter in San Francisco Bay and in Tomales Bay e. the total dry mass of trout in a lake

b. 100 sea stars, barnacles, and mussels per 25 m2 of a tide pool

In an equilibrium population (at its carrying capacity), thousands of eggs and hundreds of tadpoles are produced by a single pair of frogs. On average, about how many offspring per pair will live to reproduce? a. 0 b. 2 c. 10 to 20 d. 100 e. more than 100

b. 2

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

b. 40 individuals added

As N approaches K for a certain population, which of the following is predicted by the logistic equation? a. The growth rate will not change. b. The growth rate will approach zero. c. The population will show an Allee effect. d. The population will increase exponentially. e. The carrying capacity of the environment will increase.

b. The growth rate will approach zero.

When needed resources are unevenly distributed, organisms often show _____ dispersion pattern. a. a density-dependent b. a clumped c. an exponential d. a random e. a uniform

b. a clumped

Which of the following populations probably exhibits exponential growth? a. a protozoan population grown in a sealed glass culture flask b. a fruit fly population that recently arrived on a lush mid-oceanic island previously inhabited only by plants c. a redwood tree population in a forest d. a population of deer in an area with few palatable food plants e. a population of deer in an area with many hungry wolves

b. a fruit fly population that recently arrived on a lush mid-oceanic island previously inhabited only by plants

Chimpanzees have a relatively low birth rate. They care for their young, and most chimps live a long life. The chimp survivorship curve would look like _____. a. a line that slopes gradually upward b. a relatively flat line that drops steeply at the end c. a line that drops steeply at first, then flattens out d. a line that slopes gradually downward e. a horizontal line

b. a relatively flat line that drops steeply at the end

During exponential growth, a population always a. grows by thousands of individuals. b. grows at its maximum per capita rate. c. quickly reaches its carrying capacity. d. cycles through time. e. loses some individuals to emigration.

b. grows at its maximum per capita rate.

Carrying capacity is a. seldom reached by marine producers and consumers because of the vast resources of the ocean. b. the maximum population size that a particular environment can support. c. fixed for most species over most of their range most of the time. d. determined by density and dispersion data. e. the term used to describe the stress a population undergoes due to limited resources.

b. the maximum population size that a particular environment can support.

When the per capita birth rate equals the per capita death rate, ignoring the effects of immigration and emigration, _____. a. a population grows rapidly b. the size of a population remains constant c. density-dependent limiting factors do not affect the population d. a population is in danger of extinction e. a population goes through up and down cycles

b. the size of a population remains constant

Population ecologists are primarily interested in a. studying interactions among populations of organisms that inhabit the same area. b. understanding how biotic and abiotic factors influence the density, distribution, size, and age structure of populations. c. how humans affect the size of wild populations of organisms. d. how populations evolve as natural selection acts on heritable variations among individuals and changes in gene frequency. e. the overall vitality of a population of organisms.

b. understanding how biotic and abiotic factors influence the density, distribution, size, and age structure of populations.

Which of the following graphs illustrates the population growth curve of single bacterium growing in a flask of ideal medium at optimum temperature over a 24-hour period? a. b. c. d. e.

c.

A population is correctly defined as having which of the following characteristics? I. inhabiting the same general area II. belonging to the same species III. possessing 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

c. I and II only

Which statement is true with regard to human population growth? a. It is at a zero reproduction rate. b. Its rate of increase continues to grow at an exponential rate. c. Its rate of growth is slowing. d. Its rate of growth is increasing. e. There is no scientific prediction that can be made about human population growth.

c. Its rate of growth is slowing.

Consider two forests: one is an undisturbed old-growth forest, while the other has recently been logged. In which forest are species likely to experience exponential growth, and why? a. Old growth, because of stable conditions that 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. Logged, because the various populations are stimulated to a higher reproductive potential. e. Exponential growth is equally probable in old-growth and logged forests.

c. Logged, because the disturbed forest affords more resources for increased specific populations to grow.

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' size stable. 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 other populations. d. Those individuals that emigrate to these new populations are looking for less crowded conditions with more resources. e. Gradually, the populations of ground squirrels will move from a clumped to a uniform population pattern of dispersion

c. These immigrants provide a source of genetic diversity for the other populations.

Pine trees in a forest tend to shade and kill pine seedlings that sprout nearby. This causes the pine trees to _____. a. increase exponentially b. grow in a clumped pattern c. grow in a uniform pattern d. exceed their carrying capacity e. grow in a random pattern

c. grow in a uniform pattern

A population that is growing logistically _____. a. grows fastest when density is lowest b. has a high r c. grows fastest at an intermediate population density d. grows fastest as it approaches carrying capacity e. is always slowed by density-independent factors

c. grows fastest at an intermediate population density

A population will grow exponentially _____. a. if it is limited only by density-dependent factors b. until it reaches carrying capacity c. if there are no limiting factors d. if it is a population with an equilibrium life history e. None of the listed responses is correct.

c. if there are no limiting factors

A newly mated queen ant founds a nest in an unoccupied patch of suitable habitat. Assuming that no disasters strike the nest, which of the following types of equations is likely to best describe the population growth of the new colony over the long term? a. linear b. circular c. logistic d. exponential e. None of the listed responses is correct.

c. logistic

According to the logistic growth equation dN/dt = rmaxN(K-N)/K a. the number of individuals added per unit time is greatest when N is close to zero. b. the per capita growth rate (r) increases as N approaches K. c. population growth is zero when N equals K. d. the population grows exponentially when K is small. e. the birth rate (b) approaches zero as N approaches K.

c. population growth is zero when N equals K.

Which of the following is the best example of uniform distribution? a. bees collecting pollen in a wildflower meadow b. snails in an intertidal zone at low tide c. territorial songbirds in a mature forest during mating season d. mushrooms growing on the floor of an old growth forest

c. territorial songbirds in a mature forest during mating season

In which of the following situations would you expect to find the largest number of K-selected individuals? a. a recently abandoned agricultural field in Ohio b. a newly emergent volcanic island c. the flora and fauna of a coral reef in the Caribbean d. South Florida after a hurricane

c. the flora and fauna of a coral reef in the Caribbean

A certain species of seal breeds and rears its young on rocky beaches. Competition for breeding sites is fierce, and males that do not secure a site will not reproduce. This behavior is an example of which mechanism of density-dependent population regulation? a. competition for resources b. toxic wastes c. intrinsic factors d. predation e. territoriality

e. territoriality

The observation that members of a population are uniformly distributed suggests that a. the size of the area occupied by the population is increasing. b. resources are distributed unevenly. c. the members of the population are competing for access to a resource. d. the members of the population are neither attracted to nor repelled by one another. e. the density of the population is low.

c. the members of the population are competing for access to a resource.

Kingfish, Louisiana, had a population of 1,100 individuals. They had a birth rate of 12/100, a death rate of 8/100, an emigration (individuals leaving the population) rate of 2/100 and an immigration rate of 0/100. What was the per capita rate of increase, including emigration, for this year in Kingfish? a. 4 b. 22 c. 2 d. 0.02 e. .22

d. 0.02

To measure the population of lake trout in a 250-hectare lake, 400 individual trout were netted and marked with a fin clip, then returned to the lake. The next week, the lake was netted again, and out of the 200 lake trout that were caught, 50 had fin clips. Using the capture-recapture estimate, the lake trout population size could be closest to which of the following? a. 160 b. 200 c. 400 d. 1,600 e. 80,000

d. 1,600

Kingfish, Louisiana, had a population of 1,100 individuals. They had a birth rate of 12/100, a death rate of 8/100, an emigration (individuals leaving the population) rate of 2/100 and an immigration rate of 0/100. How many people were added to Kingfish's population in one year? a. 2 b. 6 c. 20 d. 22 e. 1,122

d. 22

In July 2008, the United States had a population of approximately 302,000,000 people. How many Americans were there in July 2009, if the estimated 2008 growth rate was 0.88%? a. 2,700,000 b. 5,500,000 c. 303,000,000 d. 304,600,000 e. 2,710,800,000

d. 304,600,000

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. 6 b. 18 c. 128 d. 64 e. 1,024

d. 64

A particular environmental change causes the deaths of 25 individuals in a herd of 100 wild horses, and it kills 50 individuals in a herd of 200 horses. In this case, the growth of a wild horse population is most likely limited by _____. (Assume that the two herds are found in territories of equal size.) a. a density-dependent factor b. food supply c. a predator d. a density-independent factor e. the presence of another species that uses the same food resource

d. a density-independent factor

A wildlife biologist is trying to predict what will happen to a bear population if bear hunting is banned. He had the equations all worked out but then realized that he had grossly underestimated the amount of food available to the bears. To make his prediction more accurate he should _____ the value of _____ in his equation. (Consider food to be a factor that limits the size of the bear population.) a. decrease ... N b. increase ... N c. decrease ... K d. increase ... K e. decrease ... r

d. increase ... K

Logistic growth of a population is represented by dN/dt = a. rN/K b. rN c. rN (K + N) d. rN (K - N)/K e. rN (N - K)/K

d. rN (K - N)/K

No population can grow indefinitely. The ultimate size of any population is limited by _____. a. its r b. its birth rate c. its death rate d. the carrying capacity of its environment e. reproductive isolation

d. the carrying capacity of its environment

What are three basic issues that life histories entail? a. when reproduction begins, how often the organism breeds, and how many offspring from each reproductive episode survive to also reproduce b. whether or not reproduction is a conscious decision, how often the organism breeds, and how many offspring are produced during each reproductive episode c. when reproduction begins, level of parental care, and how many offspring are produced during each reproductive episode d. when reproduction begins, how often the organism breeds, and how many offspring are produced during each reproductive episode e. whether or not reproduction is a conscious decision, level of parental care, and how many offspring are produced during each reproductive episode

d. when reproduction begins, how often the organism breeds, and how many offspring are produced during each reproductive episode

Which of the following graphs illustrates the growth curve of an initially small population of rodents that has grown to reach a static carrying capacity? a. b. c. d. e.

e.

A demographer may study _____. a. birth rates in a small town in Iowa b. emigration rates in a forest that has been cleared partially for farming c. offspring mortality rates in humpback whales d. immigration rates in Melbourne, Australia e. All of the listed responses are correct.

e. All of the listed responses are correct.

Which of the following is the most important assumption for the capture-recapture method to estimate the size of wildlife populations? a. All females in the population have the same litter size. b. More individuals emigrate from, as opposed to immigrate into, a population. c. Over 50% of the marked individuals need to be trapped during the recapture phase. d. There is a 50:50 ratio of males to females in the population before and after trapping and recapture. e. Marked individuals have the same probability of being recaptured as unmarked individuals during the recapture phase.

e. Marked individuals have the same probability of being recaptured as unmarked individuals during the recapture phase.

Organisms that live in a homogenous abiotic environment and cooperate to avoid being eaten would likely show a _____ pattern of dispersion. a. continuous b. uniform c. even d. random e. clumped

e. clumped

Which of the following would most likely be an example of a density-independent factor limiting population growth? a. food availability b. diseases c. accumulation of toxic waste d. parasites e. daily temperature extremes

e. daily temperature extremes

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 large numbers of gametes when employing internal fertilization versus fewer numbers of gametes when employing external fertilization. c. the emigration of individuals when they are no longer reproductively capable or immigration of more reproductively active individuals. d. producing large numbers of offspring and choosing a greater number of breeding partners e. high survival rates of offspring and the cost of parental care.

e. high survival rates of offspring and the cost of parental care.