Deck 27: Population Growth and Regulation

Question 1

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

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

Answer 1

C

Question 2

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

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

Answer 2

D

Question 3

Environmental resistance is

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

Answer 3

C

Question 4

A population size will remain stable if

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

Question 5

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

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

Question 6

Exponential growth occurs when

A) environmental resistance declines each year.
B) the number of births each year is constant and the birth rate is higher than the death rate.
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 biotic potential decreases each year.

Question 7

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

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

Question 8

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 9

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

Question 10

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

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

Question 11

Environmental resistance may limit the size of populations by

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

Question 12

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

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

Question 13

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

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

Question 14

Which species has the highest biotic potential?

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

Question 15

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

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

Question 16

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

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

Question 17

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

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

Question 18

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

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

Question 19

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

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

Question 20

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

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

Question 21

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

Question 22

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

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

Question 23

What might cause a uniform population distribution?

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

Question 24

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

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

Question 25

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) density- dependent species.
D) invasive species.
E) replacement- level fertility species.

Question 26

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

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

Question 27

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

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

Question 28

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

Question 29

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

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

Question 30

Schools of fish typically exhibit a distribution pattern.

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

Question 31

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

Question 32

A random population distribution

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

Question 33

Exponential growth occurs

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

Question 34

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

Question 35

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

Question 36

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) able to expand its carrying capacity.
E) hard to predict.

Question 37

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

Question 38

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

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

Question 39

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

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

Question 40

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

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

Question 41

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

Question 42

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

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

Question 43

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

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

Question 44

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

Question 45

At present, Earth's human population is

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

Question 46

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

Question 47

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

Question 48

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

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

Question 49

An effective parasite is one that kills its host quickly.

Question 50

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

Question 51

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

Question 52

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 53

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 54

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) Humans continue to find ways to enhance environmental quality, thus enabling more people to be supported.
B) Technological advances unforeseen at that time increased the carrying capacity to a greater extent and faster than predicted.
C) The two world wars and the AIDS crisis caused such massive mortality that the human population has stabilized.
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 55

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

Question 56

Natural populations cannot exceed their carrying capacities.

Question 57

Parasitism is a density- dependent population control.

Question 58

Interspecific competition is a density- independent factor.

Question 59

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

Question 60

A J- curve is typical of a stable population.

Question 61

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

Question 62

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

Question 63

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

Question 64

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

Question 65

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

Question 66

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

Question 67

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 68

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

Question 69

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

Question 70

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

Question 71

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

Question 72

Deforestation increases the productivity of land.

Question 73

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 74

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

Question 75

Increased population densities and increased competition lead to increased emigration.

Question 76

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

Question 77

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

Question 78

The collective human ecological footprint is now much larger than Earth's sustainable resource base.

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

Humans are classified as a late- loss population.