Deck 26: Population Growth and Regulation

Question 1

To determine the number of individuals added to a population during a given time, we multiply the growth rate (r)by the:

A)biotic potential.
B)original population size.
C)environmental resistance.
D)final population size.
E)number of immigrants.

Answer 1

B

Question 2

The different species within an ecosystem that interact in various ways make up a(n):

A)population.
B)community.
C)trophic level.
D)aggregation.
E)ecotone.

Answer 2

B

Question 3

A population grows exponentially when:

A)the birth rate and the death rate are equal.
B)the birth rate exceeds the death rate and immigration exceeds emigration.
C)emigration exceeds immigration and the birth rate equals the death rate.
D)the death rate equals the birth rate and immigration is equal to emigration.
E)the carrying capacity is exceeded.

Answer 3

B

Question 4

Which species has the highest biotic potential?

A)a fungus that produces thousands of reproductive spores every day
B)a bacteria that divides only once every 3 weeks
C)a rat that produces a litter of 6 pups every 3 months
D)an elephant that produces a single calf every 3 years
E)a lioness that produces 3 cubs once a year

Question 5

Floods and fires are examples of ________, which can dramatically and unpredictably reduce populations.

A)density-dependent factors
B)logistic growth factors
C)biotic factors
D)demographic factors
E)environmental resistance

Question 6

If a population of 100 birds increases to 120 birds in a year, what is r?

A)0)16
B)0)20
C)1)2
D)2
E)20

Question 7

A population size will remain stable if:

A)the number of births each year is constant and the birth rate is higher than the death rate.
B)the population grows by a fixed percentage of its size each year.
C)the rate of emigration is higher than the rate of immigration.
D)the birth and death rates are equal, as are the rates of emigration and immigration.
E)environmental resistance declines each year.

Question 8

Environmental resistance is:

A)limits imposed on population growth by only the living environment (such as predators or competitors).
B)limits imposed on population growth by only the nonliving environment.
C)limits imposed on population growth by both the living and nonliving environments.
D)a factor that decreases both death rates and birth rates.
E)a factor that increases both death rates and birth rates.

Question 9

Exponential growth occurs when:

A)the number of births each year is constant and the birth rate is higher than the death rate.
B)the population grows by a fixed percentage of its size each year.
C)the rate of emigration is higher than the rate of immigration.
D)the biotic potential decreases each year.
E)environmental resistance declines each year.

Question 10

What happened to the forests of Easter Island?

A)They disappeared after humans brought herbivores to the island.
B)They never existed; the island has always been barren.
C)They disappeared as a result of clear-cutting by humans.
D)They have not existed for several million years.
E)They disappeared when humans brought a tree disease to the island.

Question 11

Based on the data in the table, this population has a(n)________ growth pattern?

A)exponential
B)boom-and-bust
C)scramble competition
D)J-curve
E)S-curve

Question 12

A biologist who investigates how organisms interact with one another and with their nonliving environment is studying:

A)physiology.
B)anatomy.
C)morphology.
D)genetics.
E)ecology.

Question 13

A complex, interrelated network of organisms and the surrounding nonliving environment in a defined area is a(n):

A)community.
B)ecosystem.
C)population.
D)biosphere.
E)biome.

Question 14

Which factor does NOT influence the size a population reaches over time?

A)number of individuals migrating
B)number of deaths
C)age of females at reproduction
D)distance traveled by migrants
E)number of births

Question 15

All members of a species that reside within an ecosystem make up a(n):

A)population.
B)community.
C)trophic level.
D)aggregation.
E)ecotone.

Question 16

When a population has inhabited an area for a long time and the population size has stabilized because of space and food limitations:

A)the carrying capacity of the area has been reached.
B)density dependence is clearly not involved in the population growth.
C)predation decreases.
D)density-independent factors are involved.
E)the environmental resistance declines.

Question 17

Environmental resistance may limit the size of populations by:

A)increasing both birth and death rates.
B)decreasing both birth and death rates.
C)increasing death rates and/or decreasing birth rates.
D)decreasing death rates and/or increasing birth rates.
E)changing the biotic potential.

Question 18

An insect population grows exponentially until an early winter freeze kills almost all the insects. The next spring the population grows exponentially again. This type of population growth is called:

A)boom-and-bust cycles.
B)S-curve growth.
C)density-dependent growth.
D)density-independent growth.
E)sustained cycling.

Question 19

Based on the data in the table, this population has a ________ growth pattern.

A)replacement-level fertility
B)boom-and-bust
C)scramble competition
D)J-curve
E)S-curve

Question 20

In a deciduous oak forest in the northeastern United States, one example of a nonliving component of the ecosystem is:

A)nematodes in the soil that feed on plant roots.
B)nematodes in the soil that feed on dead organic matter.
C)sunlight that filters through the canopy.
D)animals such as deer that migrate through the forest but do not eat in the forest.
E)the smaller plants living under the oak trees.

Question 21

A random population distribution:

A)is an advantage in avoiding predators.
B)occurs when resources are evenly spaced.
C)allows predators to hunt more effectively.
D)is rare.
E)is found only in plants.

Question 22

Gum bush releases a chemical from its roots that prevents any seeds from germinating in the soil above the roots. This is an example of:

A)social competition.
B)predation.
C)parasitism.
D)contest competition.
E)scramble competition.

Question 23

Herd animals typically live in a ________ distribution pattern.

A)uniform
B)random
C)clumped
D)J-curve
E)scrambled

Question 24

Purple loosestrife was introduced into the Great Lakes region from Europe and sold as a garden flower. It produces thousands of seeds and has no natural predators there. It now clogs acres of wetlands and is considered a(n):

A)density-independent species.
B)density-dependent species.
C)predator.
D)invasive species.
E)replacement-level fertility.

Question 25

In ________ competition, one organism uses social or chemical interactions to limit the access of other individuals to resources.

A)contest
B)scramble
C)interspecific
D)intramural
E)social

Question 26

If a caterpillar eats all the seedlings in your garden, killing all of them, the caterpillar is acting as a:

A)predator.
B)parasite.
C)competitor.
D)density-independent factor.
E)saprophyte.

Question 27

When mosquitoes are abundant, purple martins flock to the area and feed exclusively on them. When mosquito populations are not large, purple martins are similarly scarce and feed on other insects. This is an example of:

A)density-independent regulation.
B)density-dependent regulation.
C)ecosystem carrying capacity.
D)community carrying capacity.
E)exotic regulation.

Question 28

If the individuals of a species are very likely to live until old age, that species exhibits a(n)________ survivorship curve.

A)convex
B)constant
C)concave
D)S-shaped
E)declining

Question 29

In areas that have a stable population, the number of children born in a period of time is:

A)increasing.
B)decreasing.
C)approximately equal to the number of adults.
D)higher than the number of adults.
E)lower than the number of adults.

Question 30

Why do many non-native species, such as a prickly pear cactus brought to Australia from South America, rapidly become abundant when first introduced?

A)The climate in the new site is more favorable than in its native site.
B)Non-native species increase their reproductive rate when introduced.
C)There are fewer predators and parasites capable of attacking the non-native species in the new site.
D)The carrying capacity at the new site is higher than at the native site.
E)Growth changes from an S-curve to a J-curve at the new site.

Question 31

Parasites affect their hosts' population sizes in a:

A)density-dependent fashion and usually directly kill the hosts.
B)density-dependent fashion and do not usually directly kill the hosts.
C)density-independent fashion and usually directly kill the hosts.
D)density-independent fashion and do not usually directly kill the hosts.
E)density-dependent fashion and do not affect host death rates.

Question 32

In a population of lemmings, a sudden freeze that caused many of the lemmings to die is an example of a:

A)nonliving and density-independent factor.
B)living and density-dependent factor.
C)nonliving and density-dependent factor.
D)living and density-independent factor.
E)normal boom-and-bust cycle.

Question 33

If most of the individuals of a species die when they are young, that species exhibits a(n)________ survivorship curve.

A)convex
B)constant
C)concave
D)S-shaped
E)declining

Question 34

In the eighteenth and nineteenth centuries, people increased Earth's capacity to support more humans through ________ advances.

A)cultural
B)agricultural
C)industrial-medical
D)social
E)demographic

Question 35

What might cause a uniform population distribution?

A)the need for a group to care for its offspring
B)allelopathy (the release of chemicals by plants to inhibit the growth of other plants nearby)
C)localization of resources
D)the need to find a mate
E)scarce resources

Question 36

Exponential growth occurs:

A)only for a limited time in natural populations.
B)only in laboratory populations.
C)frequently in natural populations.
D)at regular intervals in natural populations.
E)only in theory, never in actual populations.

Question 37

In his 1798 book, An Essay on the Principle of Population, Thomas Malthus stated: "the power of [Earth's human] population [to increase] is indefinitely greater than the power in the earth to produce subsistence for man." He explained that our population increases exponentially while we can increase our food supply only linearly. In modern terminology, what did Malthus mean by "the power in the earth to produce subsistence for man"?

A)biotic potential
B)birth rate
C)carrying capacity
D)environmental resistance
E)growth rate

Question 38

A population of rabbits introduced into an island grew rapidly for a few years and then the growth slowed down. Why did the population become stable?

A)The carrying capacity was reached.
B)Environmental resistance declined.
C)The rate of immigration declined.
D)The value of r decreased.
E)A bust cycle was about to begin.

Question 39

Which of the following is an important density-independent factor limiting population size?

A)predation
B)weather
C)environmental resistance
D)competition
E)quantity of food

Question 40

Some predators feed preferentially on the most abundant prey. This is an example of ________ predation.

A)density-dependent
B)density-independent
C)competitive
D)exponential
E)cyclical

Question 41

During the past 50 years, the amount of cropland per person has:

A)decreased by 90%.
B)decreased by more than half.
C)decreased slightly.
D)stayed about the same.
E)increased slightly.

Question 42

A J-curve is typical of a stable population. True or False?

Question 43

A forest fire is a density-independent population control factor. True or False?

Question 44

Invasive species can rapidly disrupt an ecosystem because they have a high biotic potential and face little environmental resistance. True or False?

Question 45

According to the equation for population growth rate, if two populations have the same death rates, then the population with r = 2 will increase more rapidly than a population with r = 4. True or False?

Question 46

Populations that have been relatively undisturbed by man normally grow with no limits set by their environments. True or False?

Question 47

In countries that have large numbers of children under age 15, the population is:

A)becoming larger.
B)becoming smaller.
C)staying the same.
D)hard to predict.
E)able to expand its carrying capacity.

Question 48

If all the people in the world were to live at the American level in terms of technology, wealth, education, and other factors, the population of the world would have to ________ in order to support them.

A)double
B)reduce by half
C)reduce to a fifth of the current level
D)reduce to less than a tenth of the current level
E)decrease by 90%

Question 49

The United Nations estimates that by 2050, the world's population may reach over ________ billion and still be growing.

A)7)0
B)9)0
C)12.4
D)15.6
E)20.5

Question 50

In countries where the number of children younger than 15 is approximately equal to the number between ages 15 and 45, the population is:

A)expanding slowly.
B)stable.
C)shrinking slightly.
D)growing exponentially.
E)declining drastically.

Question 51

Malthus's prediction that our human population would eventually reach a point where we cannot sustain ourselves did not occur. Why?

A)Dramatic reductions in fertility rates brought an end to population growth before the crisis point was reached.
B)Malthus was wrong; human populations can grow indefinitely
C)Technological advances unforeseen by Malthus increased the carrying capacity to a greater extent and faster than predicted.
D)The two world wars and the AIDS crisis caused such massive mortality that the human population has stabilized.
E)Humans continue to find ways to enhance environmental quality, thus enabling more people to be supported.

Question 52

As a developing country passes through the demographic transition,

A)its age structure changes but its growth rate remains unchanged.
B)its birth and death rates decrease simultaneously.
C)its growth rate first falls but later recovers.
D)first its birth rate decreases, followed by its death rate.
E)first its death rate decreases, followed by its birth rate.

Question 53

The growth rate of a population is the difference between the birth rate and the death rate. True or False?

Question 54

Parasitism is a density-dependent population control. True or False?

Question 55

When a new population stabilizes at the carrying capacity, it is described as logistic population growth. True or False?

Question 56

Interspecific competition is a density-independent factor. True or False?

Question 57

Developing countries tend to have a(n)________ age structure diagram.

A)rectangular
B)inverted triangle-shaped
C)pyramid-shaped
D)square
E)round

Question 58

An effective parasite is one that kills its host quickly. True or False?

Question 59

At present, Earth's human population is:

A)stable.
B)declining.
C)increasing exponentially.
D)increasing at a constant rate.
E)increasing by about 10% per year.

Question 60

Americans use about ________ times as much energy as the world average.

A)1)5
B)2
C)5
D)10
E)20

Question 61

The amount of land needed to meet a person's resource and waste demands is called an ecological footprint. True or False?

Question 62

Density-dependent factors become less effective as the population size increases. True or False?

Question 63

All the members of a species that live in a specific geographic region form a(n)________.

Question 64

The sum of all factors that limit the ability of a population to grow is known as ________.

Question 65

Prey, such as lemmings, may have a density-dependent effect on predator populations, such as those of the snowy owl, by enabling the predator to increase the number of its offspring at high prey densities. True or False?

Question 66

All the areas of Earth that support life make up the ________.

Question 67

In the equation "population growth = r × N," the letter r stands for ________.

Question 68

The ________ of a population is the maximum rate at which a population could increase.

Question 69

Humans are classified as a late-loss population. True or False?

Question 70

Increased population densities and increased competition lead to increased emigration. True or False?

Question 71

Within their territory, pack animals like wolves exhibit a uniform distribution. True or False?

Question 72

When resources are limited but spread evenly throughout a region, plants are likely to form a uniform distribution pattern. True or False?

Question 73

Natural populations cannot exceed their carrying capacities. True or False?

Question 74

The human population currently shows a J-curve growth pattern. True or False?

Question 75

Deforestation increases the productivity of land. True or False?

Question 76

In a constant-loss population, an organism has an equal risk of dying at any time during its life span. True or False?

Question 77

The United States has the lowest replacement-level fertility of the developed countries. True or False?

Question 78

In a stable population with neither immigration nor emigration, the replacement-level fertility is one child per woman. True or False?

Question 79

A measure of the ability of a population to grow under ideal circumstances is its ________.

Question 80

In a maple forest in the spring, the ground is often covered with young maple seedlings, which compete for light and nutrients. By fall, most of the seedlings have died, leaving only a few survivors. This is an example of ________ competition.