Deck 27: Population Growth and Regulation

Question 1

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

A) 1.2
B) 2
C) 0.20
D) 0.16
E) 20

Answer 1

C

Question 2

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

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

Answer 2

D

Question 3

When a population has inhabited an area for a long time and the population size has stabilized, then

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

Answer 3

C

Question 4

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

Question 5

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

A) Weather
B) Predation
C) Environmental resistance
D) Quantity of food
E) Competition

Question 6

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

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

Question 7

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

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

Question 8

Environmental resistance may limit the size of populations by

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

Question 9

Based on the data in the table, this population has a(n) _________growth pattern.

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

Question 10

The study of how organisms interact with one another and with their nonliving environment is

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

Question 11

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

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

Question 12

Environmental resistance is

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

Question 13

Which species has the highest biotic potential?

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

Question 14

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

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

Question 15

A population size will remain stable if

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

Question 16

Exponential growth occurs when

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

Question 17

Which factor does NOT influence the size a population reaches through natural increase?

A) Age of females at reproduction
B) Number of births
C) Number of deaths
D) Frequency of reproduction
E) Distance traveled by migrants

Question 18

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

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

Question 19

A population grows exponentially when

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

Question 20

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

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

Question 21

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

Question 22

A random population distribution

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

Question 23

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

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

Question 24

In the eighteenth and nineteenth centuries, people increased Earth?s capacity to support more humans through_________ advances.

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

Question 25

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

Question 26

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

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

Question 27

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

A) S-shaped
B) early-loss
C) constant-loss
D) late-loss
E) declining

Question 28

Some predators feed primarily on the most abundant prey. This is an example of _________predation.

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

Question 29

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

Question 30

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

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

Question 31

Which of the following correctly describes the effect parasites have on their hostʹs population size and on the host itself?

A) Parasites have a density-independent effect, and they usually kill their hosts.
B) Parasites have a density-dependent effect, but they do not usually kill their hosts.
C) Parasites have a density-dependent effect, but they do not affect host death rates.
D) Parasites have a density-independent effect, but they do not usually kill their hosts.
E) Parasites have a density-dependent effect, and they usually kill their hosts.

Question 32

What might cause a uniform population distribution?

A) Competition for resources
B) Scarce resources
C) The need to hunt in a group
D) The need for a group to care for its offspring
E) The need to find a mate

Question 33

Schools of fish typically exhibit a _________distribution pattern.

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

Question 34

A population of birds migrating to winter nesting grounds is blown off course by a late -season hurricane and ends up on an island that is uninhabited by any animal species. Which of the following represents a density-independent factor that will limit the population size?

A) Abundant fruit trees
B) Abundant berry bushes
C) Nightly temperature dropping below freezing
D) Heavily wooded
E) Freshwater spring

Question 35

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

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

Question 36

Exponential growth occurs

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

Question 37

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

A) early-loss
B) late-loss
C) S-shaped
D) constant-loss
E) declining

Question 38

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

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

Question 39

Purple loosestrife, a European plant, was introduced into the American Great Lakes region where it has no natural predators. Each plant produces thousands of seeds annually, and it now clogs acres of wetlands, crowding out native plants. Purple loosestrife is considered a(n)

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

Question 40

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

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

Question 41

Logistic population growth is characteristic of a population that moves into a new habitat, experiences a rapid increase in number, and then stabilizes.

Question 42

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.

Question 43

As a developing country passes through the demographic transition, which of the following will occur?

A) Its birth and death rates will decrease simultaneously.
B) Its age structure will change, but its growth rate will remain unchanged.
C) Its growth rate will first fall, but later recover.
D) First, its birth rate will decrease, followed by its death rate.
E) First, its death rate will decrease, followed by its birth rate.

Question 44

The prediction, during the early 1800s, that our human population would eventually reach a point where we cannot sustain ourselves has not occurred. Why?

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

Question 45

At present, Earthʹs human population is

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

Question 46

An effective parasite is one that kills its host quickly.

Question 47

A J-curve is typical of a stable population.

Question 48

Interspecific competition is a density-independent factor.

Question 49

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

Question 50

Natural populations cannot exceed their carrying capacities.

Question 51

Density-dependent factors become less effective as the population size increases.

Question 52

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

A) 15
B) 12
C) 7
D) 20
E) 9

Question 53

Populations that have been relatively undisturbed by humans normally grow, with no limits set by their environments.

Question 54

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.

Question 55

What percentage of Earthʹs productive land is currently used by the human population for crops and livestock?

A) 55%
B) 40%
C) 90%
D) 20%
E) 75%

Question 56

A forest fire is a density-independent population control factor.

Question 57

The growth rate of a population is the difference between the population size and the death rate.

Question 58

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 _________to support them.

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

Question 59

To support the world population at the same standard of living as we have in the United States would require_________ times the resources that are available on Earth today.

A) 10
B) 5
C) 1.5
D) 2
E) 20

Question 60

Parasitism is a density-dependent population control.

Question 61

When predators and prey both have population cycles, the predator cycle tends to_________that of the prey cycle.

Question 62

When parents, on average, have just the number of children required to replace themselves, the natural increase of their population is at replacement level fertility (RLF).

Question 63

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_________ life history pattern.

Question 64

The_________ is made up of the entire Earth and all of the living organisms that inhabit it.

Question 65

All the members of a species that live within an ecosystem form a(n) _________.

Question 66

Deforestation increases the productivity of land.

Question 67

Humans are classified as a late-loss population.

Question 68

In a stable population with neither immigration nor emigration, the RLF is 1.0 (one child per woman).

Question 69

A population that initially grows rapidly, then slows, and eventually stabilizes close to the carrying capacity of the environment exhibits _________population growth.

Question 70

A measure of the ability of a population to grow under ideal circumstances (maximum birth rate and minimum death rate) is its _________.

Question 71

The maximum rate at which a population could increase is known as its_________ .

Question 72

The sum of all factors (living and nonliving) that limit the ability of a population to grow is known as_________ .

Question 73

The collective human ecological footprint is now much larger than Earthʹs sustainable resource base.

Question 74

Increased population densities and increased competition lead to increased emigration.

Question 75

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

Question 76

In the equation, population growth = r × N, the letter r stands for_________ .

Question 77

Within their territory, pack animals such as wolves exhibit a uniform distribution.

Question 78

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

Question 79

Although social changes and increased access to contraceptives have caused a decrease in fertility rates in some less-developed countries, their rates are still above RLF.

Question 80

The human population currently shows a J-curve growth pattern.