Biology [CHAPTER 53] (Population Ecology)

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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

the size of the area in which they live

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

the number of Paramecium caudatum in a 250-mL solution in a glass flask

When needed resources are unevenly distributed, organisms often show a(n) _____ dispersion pattern.

A) density-dependent
B) clumped
C) exponential
D) random
E) uniform

clumped

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Organisms that live in a homogenous abiotic environment and cooperate to avoid being eaten would likely show a(n) _____ pattern of dispersion.

A) continuous
B) uniform
C) even
D) random
E) clumped

clumped

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

uniform

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

grow in a uniform pattern

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.

All of the listed responses are correct.

Life tables typically follow the fate of a cohort, a _____.

A) group of individuals who live in the same community
B) group of individuals who migrated to the same area at the same time
C) group of individuals who died from the same disease
D) group of individuals who reproduced at the same age
E) group of individuals who are the same age

group of individuals who are the same age

An oak tree produces thousands of acorns, but very few grow into mature oak trees. The oak tree exhibits a _____ survivorship curve.

A) Type I
B) Type II
C) Type III
D) Type I or II
E) Type I or III

Type III

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

a relatively flat line that drops steeply at the end

Which of the following describes the distribution of survivorship or mortality for a population that has a Type II survivorship curve?

A) Little death occurs until late in life.
B) Most of the mortality occurs among younger individuals.
C) Survivorship is greatest in younger individuals.
D) Survivorship is greatest in individuals that are intermediate in age.
E) The chance of death is roughly constant over all ages.

The chance of death is roughly constant over all ages

Kingfish, Louisiana, had a population of 1,100 individuals. They had a birth rate of 12/100, a death rate of 8/100, and an emigration (individuals leaving the population) rate of 2/100. How many people were added to Kingfish's population in one year?

A) 2
B) 6
C) 20
D) 22
E) 1,122

22

Using the data in question 12 above, 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) 0.22

0.02

When the per capita birth rate equals the per capita death rate, _____.

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

the size of a population remains constant

A population will always 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.

if there are no limiting factors

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

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

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

the carrying cpacity of its environment

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?

A) linear
B) circular
C) logistic
D) exponential
E) None of the listed responses is correct.

logistic

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

2

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

increase.....K

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.

grow increasingly rapidly

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

by a logistic equation

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

grows fastest at an intermediate population density

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

expresses the effects of population-limiting factors on exponential growth

Which sentence below summarizes the Allee effect?

A) New individuals are added to the population most rapidly at intermediate population size.
B) Individuals have a more difficult time surviving or reproducing if the population size is too small.
C) Populations adjust instantaneously and approach carrying capacity smoothly.
D) Different populations of the same species may show a balance of K-selected and r-selected traits.
E) None of the listed responses is correct.

Individuals have a more difficult time surviving or reproducing if the population size is too small.

A variety of opossum that lives on an island with no predators lives much longer than its relatives on the mainland, even when both are kept safely in a zoo. The island variant's genes have been selected for slow aging, whereas the mainland variant's genes have been selected for quick reproduction. The island opossum exhibits _____ selection, and the mainland opossum exhibits _____ selection.

A) r ... K
B) K ... r
C) nutrient ... territory
D) iteroparity ... semelparity
E) clumped ... uniform

K ... r

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

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

A dog gives birth to three puppies one year. Three years later, she gives birth to six puppies. Which type of life history pattern is characteristic of this organism?

A) semelparity
B) exponential population growth
C) big-bang reproduction
D) iteroparity
E) r-selection

iteroparity

Although there are organisms whose life histories fall somewhere between iteroparity and semelparity, life history always represents a trade-off. Why is this?

A) Parents always try to leave adequate resources for their offspring, so the parents may suffer.
B) The energy cost of reproduction is high, so there are not enough resources to reproduce often, produce many offspring, and take care of them.
C) In unpredictable environments iteroparity is favored because it may require many attempts to successfully reproduce.
D) Where resource competition is intense, semelparity is favored because, of the many offspring produced, only a few will survive.
E) All of the listed responses are correct.

The energy cost of reproduction is high, so there are not enough resources to reproduce often, produce many offspring, and take care of them.

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 wastes
D) parasites
E) daily temperature extremes

daily temperature extremes

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

territoriality

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

a density-independent factor

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 decrease in clutch size

The cyclic growth exhibited by populations of snowshoe hares in the North American taiga most likely results from _____.

A) predation by lynx
B) fluctuations in the hare's food resources
C) predation by lynx and fluctuations in the hare's food resources
D) hunting by humans
E) weather changes

predation by lynx and fluctuations in the hare's food resources

If you wanted to determine what percentage of the population of Thailand is less than 10 years old, you could look at _____.

A) a logistic curve for the population
B) the population's age structure
C) a life table for the population
D) a plot of population density
E) the population's survivorship curve

the population's age structure

An ecologist would suspect a population to be growing rapidly if it _____.

A) contains many more prereproductive 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

contains many more prereproductive than reproductive individuals

What absolutely essential resource is likely to limit the carrying capacity of Earth for humans?

A) oil
B) raw materials such as metals
C) water
D) space
E) oxygen

water

To calculate the _____ of a nation, researchers summarize arable land, pasture, fossil energy land, and several other factors appropriated by each nation to produce all of the resources it consumes and to absorb all the waste it generates.

A) ecological footprint
B) carrying capacity
C) ecological capacity
D) principles of energy flow
E) life history

ecological footprint

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