Deck 34: Population and Community Ecology

Question 1

An ecosystem contains

A) only the biotic (living) components of the environment.
B) only the abiotic (nonliving) components of the environment.
C) only the energy flow components of an environment.
D) both the living organisms and the abiotic components of the environment.
E) only the food relationships found in an environment.

Answer 1

D

Question 2

All of the organisms living in your front yard represent a(n)

A) population.
B) ecosystem.
C) species.
D) community.
E) trophic level.

Answer 2

D

Question 3

List the features used to identify a species as opportunistic (r-strategist).

Answer 3

small individuals
short life span
fast to mature
many offspring
little or no parental care of offspring
many offspring die before reaching reproductive age
early reproductive age

Question 4

Biotic potential depends on

A) the number of offspring per reproduction.
B) how often each individual reproduces.
C) chances of survival until the age of reproduction.
D) the age at which reproduction begins.
E) All of the answer choices describe factors that affect biotic potential.

Question 5

Explain the species interactions in each of the following symbiotic relationships: parasitism, commensalism, and mutualism.

Question 6

The relatively thin layer on the earth's surface where life is possible is known as the

A) ecosystem.
B) biosphere.
C) biome.
D) biopreserve.
E) lithosphere.

Question 7

The maximum per capita rate of increase for a population that can occur under ideal conditions is the

A) population growth.
B) biotic potential.
C) environmental resistance.
D) carrying capacity.
E) doubling time.

Question 8

A scientist observes a population of grasshoppers in a farm field several times over the summer. She notices that each time she visits, the population has doubled in size. The scientist's results indicate the grasshopper population is probably

A) in the lag phase.
B) in the exponential growth phase.
C) decelerating.
D) in the stable equilibrium phase.
E) at carrying capacity.

Question 9

Population growth rate would be negative when

A) birthrate is greater than death rate.
B) death rate is greater than birthrate.
C) all couples are married but average less than two children apiece.
D) a country becomes poorer, because it is related to economic growth.
E) better health care reduces the death rate and increases survivorship of newborns.

Question 10

Which of the following impacts an organism's biotic potential?

A) number of offspring per reproduction
B) chances of survival until age of reproduction
C) age at which reproduction begins
D) how often each individual reproduces
E) All of the answer choices describe factors that can affect the biotic potential of an organism.

Question 11

When growth proceeds at a rate similar to 2 → 4 → 8 → 16 → 32 → 64...etc., it is called

A) arithmetic growth.
B) logistic growth.
C) exponential growth.
D) zero population growth.
E) carrying capacity.

Question 12

Ecology is best defined as the study of

A) populations.
B) the rate of population changes.
C) communities.
D) how populations are restricted by environmental resistance.
E) the interactions between organisms and with their physical surroundings.

Question 13

Which of the following is a form of environmental resistance?

A) limited food supply
B) accumulation of waste products
C) predation
D) limited living space
E) All of the answer choices describe environmental resistance factors.

Question 14

When the number of births exceeds the number of deaths, this results in

A) population growth.
B) biotic potential.
C) environmental resistance.
D) carrying capacity.
E) population decrease.

Question 15

All the members of the same species that inhabit a particular area are termed a(n)

A) ecosystem.
B) biosphere.
C) ecological niche.
D) population.
E) community.

Question 16

A number of populations of different species interacting with one another is called

A) competition.
B) a community.
C) an ecosystem.
D) predation.
E) symbiosis.

Question 17

Explain the correct sequence of events that occurs during the secondary succession of a forest.

Question 18

The study of the interrelationships of living organisms with one another and with their environment is known as

A) a trophic level.
B) a food web.
C) a habitat.
D) a biosphere.
E) ecology.

Question 19

Consider that a species of salmon lays 20,000 eggs per pair when it spawns and dies. At the end of five years, an average of one pair of mature salmon from this group of hatched eggs returns again to spawn in the parent stream (19,998 have died). What is the per capita rate of increase?

A) 10,000, because there were that many eggs produced per parent fish (r)
B) 2,000, because this must be divided by five years
C) zero, because there is exact replacement of the previous generation
D) -2,000, because there was this much average die-off per year
E) -19,998, because there was this much total loss

Question 20

Which of the following would allow optimal population growth?

A) accumulation of waste products
B) predation
C) competition
D) limited access to food and water
E) unlimited resources

Question 21

A population age structure diagram which shows the number of people in the pre-reproductive class is roughly equal to the number in the reproductive age class would be

A) bell shaped.
B) narrow and roughly rectangular in shape.
C) pyramid shaped.
D) shaped like an inverted triangle.
E) irregularly shaped.

Question 22

The demographic transition, where population growth slows in developed countries, is due to a(n)

A) decreased death rate followed by a decreased birthrate.
B) decreased death rate followed by increased birthrate.
C) increased death rate followed by a decreased birthrate.
D) increased death rate followed by increased birthrate.
E) loss of a large number of young adults.

Question 23

When growth stops, a population has reached

A) a lag phase.
B) its maximum biotic potential.
C) minimum biotic potential.
D) carrying capacity.
E) the end of its evolution.

Question 24

Which of the following describes a type II survivorship curve?

A) Most individuals die of old age.
B) Many individuals die early in life.
C) Individuals die at a constant rate throughout time.
D) Most individuals die during their reproductive years.
E) Most individuals die before old age, but after their reproductive years.

Question 25

The human growth curve is best described as being

A) flat.
B) J-shaped.
C) V-shaped.
D) S-shaped.
E) W-shaped.

Question 26

The maximum population that the environment can support for an indefinite period of time is called the

A) biotic potential.
B) environmental resistance.
C) carrying capacity.
D) replacement reproduction.
E) demographic transition.

Question 27

Replacement reproduction occurs when

A) the number of births equals the number of deaths.
B) each couple has an average of two children, which also results in zero population growth.
C) each couple has an average of two children, but population growth may still occur.
D) the population reaches carrying capacity.
E) all of the adult population is married.

Question 28

The demographic transition, where population growth slows in developed countries, may be attributed at least in part to

A) socialization.
B) sensitivity.
C) an increase in family size.
D) better medical care.
E) education.

Question 29

Which of the following human populations would be expected to have the greatest increase in growth rate?

A) A population with the majority of their population over 50 years of age.
B) A population with its population distributed equally across all age ranges.
C) A population with most of its population under the age of 18 years.
D) A population with most of the population in middle age.
E) A population with most of its population over the age of 30 years.

Question 30

If the growth rate of a population increases, the doubling time

A) increases.
B) decreases.
C) remains the same.
D) depends on the amount of natural resources.
E) is not related to growth rate increase.

Question 31

The carrying capacity of the environment for a species is determined by

A) the reproductive rate of the organism.
B) the number of organisms of that species.
C) the state and national wildlife laws pertaining to that species.
D) a complex "balance of nature" that still has not been explained in terms that scientists can calculate.
E) the limited productivity of the environment and the environmental resistance to the biotic potential of the organism.

Question 32

Which of the following statements accurately describes the less developed countries?

A) high birthrate, large pre-reproductive portion of the population
B) high birthrate, different age groups of equal size
C) low birthrate, the largest portion of the population is elderly
D) low birthrate, different age groups of equal size
E) high growth rate, different age groups of equal size

Question 33

Which of the following is a density-independent factor?

A) food supply
B) weather
C) shelter or nest space
D) disease
E) predators

Question 34

Which of the following describes a type III survivorship curve?

A) Most individuals die of old age.
B) Many individuals die early in life.
C) Individuals die at a constant rate throughout time.
D) Most individuals die during their reproductive years.
E) Most individuals die before old age, but after their reproductive years.

Question 35

Age structure diagrams with a broad base suggest that

A) the population will continue to grow for some time.
B) environmental resistance is preventing population growth.
C) the biotic potential is decreasing.
D) many individuals are migrating into the population.
E) there are many older individuals in a population.

Question 36

Replacement reproduction cannot bring about zero population growth unless

A) all diseases such as cholera, typhus, and diphtheria are eradicated.
B) there are many fatalities due to a world war.
C) there are as many older women leaving the reproductive years as there are younger women entering them.
D) there are more older women leaving the reproductive years than there are younger women entering them.
E) there are fewer older women leaving the reproductive years than there are younger women entering them.

Question 37

Consider the life of the praying mantis. The large predatory female lays several hundred eggs in a foam mass in the fall. The young are most vulnerable when they emerge in the spring, but the few that survive spread out over the countryside and, if they find a mate, lay eggs the following fall. Which type of survivorship curve does this represent?

A) type I
B) type II
C) type III
D) type I or II
E) There is not enough information given to determine the type of survivorship curve.

Question 38

Which of the following describes a type I survivorship curve?

A) Most individuals die of old age.
B) Many individuals die early in life.
C) Individuals die at a constant rate throughout time.
D) Most individuals die during their reproductive years.
E) Most individuals die before old age, but after their reproductive years.

Question 39

Which of the following is a true statement about growth rate?

A) The growth rate can be positive and a population can still be the same size year after year.
B) The growth rate has to be zero before a population can be the same size year after year.
C) Replacement reproduction automatically gives a growth rate of zero.
D) A growth rate of zero means the population is dying.
E) The growth rate can be negative and a population can still be the same size year after year.

Question 40

A population with rapidly expanding exponential growth would be best represented by a graph with a(n) ________-shaped curve.

A) bell
B) bimodal
C) pyramid
D) S
E) J

Question 41

Which of the following is an anti-predator defense mechanism?

A) Plant chemicals, including coffee and tea caffeine, make caterpillars sick or jittery.
B) The large eyespots on a moth's wing are exposed abruptly to startle a hungry bird.
C) Many trees, vines, and shrubs have stems lines with long thorns.
D) Prairie dog towns always have several prairie "watchdogs" to alert them of approaching hawks and snakes.
E) All of the answer choices describe anti-predator defense mechanisms.

Question 42

Interaction between two species as both attempt to use the same environmental resources is

A) competition.
B) commensalism.
C) parasitism.
D) predation.
E) symbiosis.

Question 43

An intimate relationship between two different species is called

A) competition.
B) exclusion.
C) mimicry.
D) predation.
E) symbiosis.

Question 44

Black-and-yellow stripes are a common warning coloration. Among a set of insects that possess black-and-yellow patterns are: -female wasps that sting
-male wasps that do not sting
-a tasty, harmless, and nutritious leaf beetle
-an acrid blister beetle that makes you sick if you eat it
-a harmless hover fly that sounds and looks like a bee
This assortment represents

A) all organisms that share black and yellow because it evolved in a common ancestor.
B) all cases of Batesian mimicry.
C) all cases of Müllerian mimicry.
D) a combination of cases including both Müllerian and Batesian mimicry.
E) warning coloration only in the cases of the female wasp and blister beetle; the other cases are not mimicry.

Question 45

The role a species plays in the community is called its

A) habitat.
B) ecological niche.
C) biotic role.
D) abiotic role.
E) ecology.

Question 46

The outbreak of a disease, such as the bubonic plague, that kills large numbers of people in a city is an example of

A) a density-independent factor.
B) a density-dependent factor.
C) a commensalistic factor.
D) a symbiotic relationship.
E) predation.

Question 47

There are two organisms with overlapping ranges that fill a similar niche. Where their niches overlap, there is strong competition for resources. This will eventually lead to

A) speciation.
B) emigration.
C) competitive exclusion.
D) total extinction of one species.
E) cooperative sharing of the resources.

Question 48

Interaction between two species in which one feeds on the other is

A) competition.
B) mimicry.
C) mutualism.
D) predation.
E) symbiosis.

Question 49

What would happen to the effectiveness of Batesian mimicry if many more harmless prey species in the population evolve this type of mimicry? In comparison, what would happen to the effectiveness of Müllerian mimicry if a species that tastes bad evolves to resemble a species that stings?

A) The effectiveness of Müllerian mimicry would be reduced, but the effectiveness of Batesian mimicry would be strengthened.
B) The effectiveness of Batesian mimicry would be reduced, but the effectiveness of Müllerian mimicry would be strengthened.
C) The effectiveness of both Batesian and Müllerian mimics would be reduced.
D) The effectiveness of both Batesian and Müllerian mimics would be strengthened.
E) There would be no change in the effectiveness of either type of mimicry.

Question 50

An example of two similar species occupying slightly different niches in the same community would be

A) the presence of carp in polluted waters in the United States.
B) the fluctuation of the snowshoe hare and lynx populations in Canada.
C) the competition between two species of barnacles in Scotland, resulting in one living in the high areas of the intertidal zone and the other species living in the low areas of the intertidal zone.
D) removal of a starfish species from intertidal communities in Washington.
E) killing dingoes in Australia or coyotes in the American West.

Question 51

Which statement about parasitism is true?

A) The host is generally smaller than the parasite.
B) Parasites always kill the host.
C) All parasites require a single host for their life cycle.
D) There are examples of parasites in every kingdom of life.
E) All parasites will remain attached to their host for the entire life span of the host.

Question 52

A small marine amphipod has recently been discovered that carries another organism on its back. The "backpack" organism tastes bad. If a fish ingests the pair, it immediately spits them back out. If the amphipod is alone, however, it is readily eaten and swallowed. There is no apparent benefit in this relationship for the "backpack" organism, which appears to be neither helped nor harmed. This is therefore a case of

A) mutualism.
B) parasitism.
C) commensalism.
D) competitive exclusion.
E) predation.

Question 53

A form of symbiosis in which one participant benefits while the other is unaffected is called

A) commensalism.
B) parasitism.
C) mutualism.
D) coevolution.
E) symbiosis.

Question 54

The harmless orange-and-black viceroy butterfly closely resembling the toxic orange-and-black monarch butterfly is an example of

A) Müllerian mimicry.
B) Batesian mimicry.
C) both Müllerian and Batesian mimicry.
D) a case of resource partitioning.
E) a case of competitive exclusion.

Question 55

In an Asian rice paddy, carp eat algae around the base of rice plants while a snail scrapes algae from the leaves and stem. The carp and snails can coexist in the same rice paddy because they

A) occupy the same habitat but use the resources differently.
B) occupy the same habitat and use the same resources.
C) use the same resources but occupy different habitats.
D) occupy different habitats and use the resources differently.
E) work according to the competitive exclusion principle.

Question 56

Which of the following is correct when describing a predator-prey cycle?

A) A decline in the number of predators causes a decline in the number of prey.
B) A decline in the number of prey causes a decline in the number of predators.
C) An increase in the number of predators triggers an increase in the number of prey.
D) An up-and-down cycle will be seen for the prey animal.
E) A seasonal die-off in prey will occur while the predator species hibernates.

Question 57

Organisms that are parasites

A) are classified as either viruses, bacteria, or protists.
B) are classified as viruses, bacteria, protists, or animals. There are no plant parasites.
C) are found only on host animals.
D) are only found on one type host for their entire life span.
E) are found in all kingdoms, and will sometimes use more than one host during its lifetime.

Question 58

The division of feeding niches in a community is known as

A) competitive exclusion.
B) resource partitioning.
C) predation.
D) hybridization.
E) competition.

Question 59

Several species of grain beetles can live on dry meal, obtaining water from their metabolic reactions. Many of these beetle species are grain pests that do considerable damage to stored grain. You set up an experiment with a dozen jars of dry meal. In each jar you introduce 50 individuals from each of two species. The food supply is sufficient to last for a year, and the size of the jar is adequate to prevent toxic waste buildup. In 6 months, when you reexamine the jars, you will most likely find

A) a totally random number of organisms from both beetle species.
B) only one species per jar, similar to the classic competitive exclusion principle experiment with paramecia.
C) the same ratio of beetles as when you started, about half from each species.
D) only dead beetles in all jars due to intense competition.
E) a new species of hybrid beetles in each of the jars.

Question 60

Which of the following is a parasitic relationship?

A) The Dutch elm disease fungus infects and kills elm trees.
B) The yellow fever virus causes fever and sometimes kills humans.
C) A female tick fastens to the skin of a human host and draws blood for nutrition to make her eggs.
D) The trichina worm burrows into muscle tissue, forms a cyst, and waits to continue its cycle until a predator consumes the host.
E) All of the answer choices describe parasitic relationships.

Question 61

The climax-pattern model states that the same area will always lead to a specific type of community if it is given a sufficient amount of time. Which of the following statements is true of this model?

A) In recent times, this has been modified to recognize that while the area may return to the same community it may not have exactly the same species diversity.
B) In an area that has been disturbed, succession will result in the same community with the exactly same species diversity.
C) In an area that has been disturbed, succession will result in an entirely new community.
D) In an area that has been disturbed, primary succession must occur before secondary succession can reestablish the climax community.
E) In recent time, this model has been changed to state that the climax community cycles through a series of different dominant species.

Question 62

A form of symbiosis in which both participants benefit is

A) commensalism.
B) parasitism.
C) mutualism.
D) predation.
E) competition.

Question 63

You are on vacation in the Canadian Rocky Mountains and you observe that a massive forest fire has burned all the trees off the side of the mountain. The type of succession that occurs following the fire is

A) secondary succession.
B) tertiary succession.
C) primary succession.
D) primary soil leaching.
E) facilitated succession.

Question 64

One model of succession predicts that different types of plants can all colonize an area at the same time and it is chance alone that determines which one arrives first and begins the process of succession. This model is called

A) the facilitation model.
B) the tolerance model.
C) the inhibition model.
D) an opportunistic model.
E) the climax model.

Question 65

An example of commensalism is

A) mycorrhizal fungal roots on the roots of plants.
B) ants living on the bullhorn acacia tree.
C) termites with protozoa in their digestive tracts.
D) flowering plants and their pollinators.
E) clown fishes in sea anemones.

Question 66

A population of 1,000 mice living in a barn loses one-half of its members when a sudden virus spreads through the population. This population has undergone a reduction in population size due to

A) an intrinsic factor.
B) a density-independent factor.
C) a density-dependent factor.
D) natural selection.
E) an opportunistic control.

Question 67

In a pine forest, very few other species of plants can grow underneath the pine trees because pine needles make the soil very acidic. This is an example of

A) the facilitation model.
B) the tolerance model.
C) the inhibition model.
D) an opportunistic model.
E) the climax model.

Question 68

Secondary succession occurs where is there is bare rock.

Question 69

In a mutualistic relationship, one species benefits while the other is harmed.

Question 70

A population of 100 butterflies living on an acre of land loses three-quarters of its members when a sudden freeze in the spring occurs just after they emerge as caterpillars. This population has undergone a reduction in population size due to

A) an intrinsic factor.
B) a density-independent factor.
C) a density-dependent factor.
D) natural selection.
E) an opportunistic control.

Question 71

Primary succession takes much longer than secondary succession because it involves

A) colonization by more equilibrium species.
B) time for weathering of rock and development of the soil horizons.
C) more time for development of a seed bank.
D) colonization by organisms that are farther away.
E) redevelopment of the atmospheric gases.

Question 72

The idea that plants are unable to grow in a particular area until the soil has been enriched by an earlier community is the

A) climax-pattern model.
B) facilitation model.
C) inhibition model.
D) tolerance model.
E) soil development model.

Question 73

In a population of 150 organisms, over a six-month period, there are 75 births and 30 deaths. Calculate the growth rate for those six months.

A) 0.7
B) 0.5
C) 0.2
D) 0.3
E) 0.75

Question 74

The climax community in a biome that receives a large amount of rainfall would include

A) plants with high tolerance to full sun, limited water, and limited nutrients.
B) the pioneer community.
C) small native plants of the area such as grasses and herbs.
D) large plants such as shrubs and trees.
E) lichens, mosses, and ferns.

Question 75

At the basic level, an ecologist will study how an organism is adapted to its environment.

Question 76

There are two plowed fields that are both the same size, have the same soil composition and climate. Both fields are surrounded by woodland. In the first field, as succession begins, the pioneer species are pine trees and shrubs. In the second field, the pioneer species are weeds and shrubs. This provides evidence for which model of succession?

A) the facilitation model
B) the tolerance model
C) the inhibition model
D) an opportunistic model
E) the climax model

Question 77

In a population of 10,000 organisms, over a one-year period, there are 750 births and 130 deaths. Calculate the growth rate for that year.

A) 0.062
B) 0.055
C) 0.088
D) 0.013
E) 0.075