Deck 11: Population Distributions

Question 1

Which of these measurements is NOT an example of density?

A) 26.8 rabbits per hectare
B) 17 birds per square mile
C) 13 colonies per square metre
D) 1021 bacteria per cubic centimetre

Answer 1

C

Question 2

The number of individuals _____ best defines abundance.

A) per unit area or volume
B) in a defined area
C) in a geographic range
D) in a species

Answer 2

B

Question 3

The orange-breasted sunbird (Anthobaphes violacea) lives only in the fynbos region in the Western Cape of South Africa. This is an example of

A) an extinct species.
B) an endemic species.
C) a cosmopolitan species.
D) a localized species.

Answer 3

B

Question 4

A species of tree is found from the Canadian border down to the southeast United States. This is called the species'

A) fundamental niche.
B) realized niche.
C) geographic niche.
D) geographic range.

Question 5

How do dispersal and migration differ?

A) Dispersal is seasonal, and migration is usually permanent.
B) Dispersal is usually permanent, and migration is seasonal.
C) Dispersal is back-and forth-movement between two areas, and migration is unidirectional.
D) Migration is movement to colonize a new habitat, and dispersal is seasonal movement.

Question 6

Which dispersion should be favoured among plants that compete intraspecifically by casting shade?

A) clumped
B) evenly spaced
C) random
D) clustered

Question 7

Sugar maple (Acer saccharum) is a tree species that is found throughout the northeastern United States in higher-elevation sites without sandy soils. What can you conclude about the distribution of sugar maples in terms of their geographic range and realized niche?

Question 8

What was the main factor that led to declines in collared lizard (Crotaphytus collaris) populations in the Ozark Mountains of Missouri in the United States?

A) Increased forest fires killed collared lizards and their preferred insect prey species.
B) Suppression of forest fires decreased the open habitat that collared lizards require.
C) Increased forest fires removed the cool, closed-canopy habitat that collared lizards require.
D) Suppression of forest fires led to an increase in the populations of collared lizard predators.

Question 9

Species with very large geographic ranges that can span several continents are called

A) abundant.
B) endemic.
C) cosmopolitan.
D) dispersed.

Question 10

What is the difference between a species' realized niche and its ecological envelope?

A) The ecological envelope is the range of conditions under which a species lives, whereas the realized niche is a prediction of the range of conditions under which a species can live.
B) The realized niche is the range of conditions under which a species lives, whereas the ecological envelope predicts the range of conditions under which a species can live.
C) The realized niche is the range of conditions under which a species lives, whereas the ecological envelope is a measure of the total area in which a population lives.
D) The realized niche and the ecological envelope are essentially the same.

Question 11

(Figure 11.5) Researchers examined data collected between 1985 and 2006 on diversity of fish in the North Sea, average bottom temperatures, and how species diversity was affected by temperature. According to the figure, what did they find? What did they conclude about the cause of the change in fish diversity?

Question 12

The pattern of density and spacing of individuals in a population is called the

A) niche.
B) ecological envelope.
C) spatial structure.
D) geographic range.

Question 13

The range of abiotic conditions under which a species can persist is called its

A) fundamental niche.
B) geographic niche.
C) realized niche.
D) geographic range.

Question 14

What type of dispersion do many agricultural crops exhibit?

A) random
B) clustered
C) even
D) clumped

Question 15

Populations whose individuals _____ favour clustered dispersion.

A) live in social groups
B) directly interact with one another
C) aggressively defend resources
D) do not interact with one another

Question 16

When there are direct interactions among individuals in a population, _____ dispersion is favoured.

A) random
B) clustered
C) clumped
D) evenly spaced

Question 17

When a species is in danger of becoming extinct, scientists use ecological niche modelling to assess where the species might have the highest probability of successful reintroductions. What does ecological niche modelling determine?

A) geographic range
B) fundamental niche
C) realized niche
D) ecological envelope

Question 18

An endangered frog species lives in only a few forest patches found throughout the Pacific Northwest of the United States. The Pacific Northwestern United States is its _____ and the forest patches are its _____.

A) realized niche; geographic range
B) fundamental niche; realized niche
C) geographic range; realized niche
D) geographic range; fundamental niche

Question 19

Why are endemic species more at risk for becoming rare or endangered than cosmopolitan species?

Question 20

Determining the suitable habitat conditions for a species is called _____ modelling.

A) fundamental niche
B) ecological niche
C) geographic niche
D) spatial structure

Question 21

Measuring the lifetime dispersal distance of a species helps scientists to estimate how rapidly a growing population can increase its

A) geographic range.
B) fundamental range.
C) realized niche.
D) fundamental niche.

Question 22

Based on the relationship between geographic range and population, what would you expect to happen if a large portion of a species' habitat is converted to agriculture?

Question 23

Populations with high abundance tend to have a _____ range.

A) small geographic
B) small fundamental
C) large geographic
D) large fundamental

Question 24

Which of the following populations would be best estimated by an area-based survey?

A) flowers in a field
B) rodents in a grassland
C) fish on a coral reef
D) migratory birds on a pond

Question 25

Ants should live in _____ populations, and rhinoceroses should live in _____ populations.

A) high-density; high-density
B) low-density; low-density
C) high-density; low-density
D) low-density; high-density

Question 26

What factors drive the relationship between population density and adult body size?

A) resources and predation
B) space and predation
C) availability of mates and predation
D) space and resources

Question 27

The best way to quantify organisms that are well camouflaged is a(n) _____ survey.

A) line-transect
B) mark-recapture
C) volume-based
D) area-based

Question 28

Compare and contrast the terms dispersion and dispersal.

Question 29

If the geographic range of a population is decreased,

A) the size of the population will decrease.
B) the size of the population will increase.
C) the population will go extinct.
D) the size of the population will stay the same.

Question 30

During the annual Christmas bird count conducted by the Audubon Society, volunteers count the number of individuals of every bird species they can see or hear within a 24-kilometre circle. This is an example of a(n) _____ survey.

A) volume-based
B) area-based
C) mark-recapture
D) line-transect

Question 31

Why does reduction of a population lead to decreased geographic range?

A) Fewer individuals need fewer resources.
B) Populations will clump tightly when populations reduce.
C) Smaller populations use fewer resources per capita.
D) Marginal habitats will receive fewer dispersing individuals.

Question 32

What is the relationship between population density and adult body size?

A) Population density is positively correlated to adult body size.
B) Population density is negatively correlated to adult body size.
C) Populations with high density generally have large-bodied species.
D) Populations with low density generally have small-bodied species.

Question 33

Answer:
Imagine that you are conducting a mark-recapture survey of common pill bugs (Armadillidium vulgare), a terrestrial isopod, in a field. Unbeknownst to you, the majority of the pill bugs molt between marking and recapturing. How does this affect your estimate of the population size? How could you have foreseen this? How could you prevent this in the future?

Question 34

A researcher who wants to know how many tree seedlings are in a 1-hectare site counts the number of seedlings within five 2-square-metre subplots and then calculates the average. This method of determining the number of individuals in an area is known as a

A) census.
B) survey.
C) tally.
D) count.

Question 35

A researcher counts the number of individuals of a tree species between two fixed points is making a(n) _____ survey.

A) area-based
B) volume-based
C) line-transect
D) mark-recapture

Question 36

For a mark-recapture survey, the ratio of the number of marked individuals to the total population is equal to the ratio of the

A) number of marked individuals recaptured to the total number of individuals in the second capture.
B) total number of individuals in the second capture to the number of marked individuals recaptured.
C) total number of individuals in the first capture to the number of marked individuals recaptured.
D) number of individuals in the second capture to the number of individuals marked in the first capture.

Question 37

Dispersal limitation occurs when

A) there has not been sufficient time for a species to disperse into suitable habitat.
B) there is a barrier to dispersal into suitable habitat.
C) the new habitat is unsuitable for the species.
D) the new habitat is already occupied by a competing species.

Question 38

The relationship between population density and adult body size is demonstrated in many organisms. Would you expect this relationship to hold true for body size averaged across all developmental stages (juveniles to adults)? Why or why not?

Question 39

Scientists commonly use _____ dispersal distance to quantify an organism's dispersal.

A) average
B) maximum
C) lifetime
D) median

Question 40

Methods such as area-based, volume-based, and line-transect surveys would be best for estimations of _____ populations.

A) clustered
B) random
C) evenly spaced
D) All of the above.

Question 41

Which model specifically addresses the situation in which subpopulations in poor-quality habitats are maintained by immigration of individuals from other subpopulations that produce surplus individuals?

A) the basic metapopulation model
B) the source-sink metapopulation model
C) the landscape metapopulation model
D) the habitat metapopulation model

Question 42

Which of the following is an example of dispersal limitation?

A) A species of bird is not aware of the habitat.
B) The preferred prey of a species of lizard is absent.
C) All mice that try to cross the highway to reach the new habitat are killed.
D) The soil moisture in the habitat is too low for a species of tree.

Question 43

The emerald ash borer (Agrilus planipennis) is an insect from eastern Asia that has invaded North America. The larvae of the emerald ash borer consume the cambium and phloem under the bark of American ash trees and eventually kill the trees. How can biologists predict the spread of this invasive pest? What might explain why the emerald ash borer is more of a problem in North America than in its native range?

Question 44

When a larger population is broken up into smaller groups that live in isolated patches, the smaller groups are called

A) subpopulations.
B) copopulations.
C) side populations.
D) sink populations.

Question 45

Which population model applies to the situation in which patches of suitable habitat are embedded within a matrix of unsuitable habitat?

A) the basic metapopulation model
B) the basic subpopulation model
C) the source-sink metapopulation model
D) the landscape metapopulation model

Question 46

In the experiment in which stickleback fish (Gasterosteus aculeatus) were presented with high- and low-quality habitats, why did fish disperse from the high-food side of the aquarium to the low-food side?

A) The low-food side increased in quality.
B) The high-food side decreased in quality.
C) The low-food side per capita benefit equaled that of the high-food side.
D) The low-food side per capita benefit was less than the high-food side.

Question 47

In populations that fit a source-sink metapopulation model, organisms in _____ subpopulations disperse into _____ subpopulations.

A) higher-quality sink; lower-quality source
B) lower-quality sink; higher-quality source subpopulations
C) lower-quality source; higher-quality sink subpopulations
D) higher-quality source; lower-quality sink subpopulations

Question 48

Which of the following does NOT explain why an ideal free distribution might not be achieved in nature?

A) Individuals may not be aware that other habitats exist.
B) An individual's fitness is not solely determined by maximizing its resources.
C) Presence of predators or territoriality may preclude free movement between habitats.
D) Individuals may not be able to differentiate between high- and low-quality habitat.

Question 49

Although there is suitable habitat for sugar maple (Acer saccharum) in Europe and Asia, it is limited to North America because of lack of

A) habitat corridors to Europe and Asia.
B) dispersal limitation to Europe and Asia.
C) pollinators in Europe and Asia.
D) sufficient soil nutrients in Europe and Asia.

Question 50

(Figure 11.14) Researchers used an experimental design in which they cleared large patches of pine forest in five areas. The central cleared area served as the source of dispersers. The four remaining cleared patches were (1) a rectangular unconnected patch, (2) a rectangular patch connected to the central patch by a cleared path that served as a corridor, (3) two rectangular patches with wings (patches with corridors that did not connect to other patches). The researchers were interested in the importance of habitat corridors to the movement of seeds, pollen, and butterflies between central and peripheral habitat patches. What was the purpose of the unconnected winged patches?

Question 51

Which of the following is NOT a characteristic of a source subpopulation?

A) high-quality habitat
B) high emigration rate
C) high level of resources
D) high immigration rate

Question 52

Per capita benefit is the amount of resources

A) per individual.
B) for the total population.
C) per group of individuals.
D) per species.

Question 53

In some parts of the United States, pathways for wildlife are built over or under highways to allow animals to cross safely. This is an example of

A) a dispersal limitation.
B) a habitat corridor.
C) an ecological envelope.
D) an ecological passage.

Question 54

When individuals have perfect knowledge of habitat variation and distribute themselves in a way that allows all of them to have the same per capita benefit, they display a(n) _____ free distribution.

A) optimum
B) ideal
C) perfect
D) best

Question 55

A southern European songbird, the blue tit (Parus caeruleus), breeds in two habitats that differ greatly in quality: downy oak forest and holm oak forest. In downy oak habitats, there are six times as many breeding pairs of blue tits and they produce 60 percent more total offspring per year than the holm oak blue tit populations. The downy oak blue tit populations have the potential to grow at the rate of 9 percent annually. In holm oak habitats, blue tits perform poorly and populations have the potential to decline 13 percent annually. Given the differences in the two habitats, why do blue tits persist in both? Be sure to include a discussion of the relevant metapopulation model in your answer.

Question 56

Researchers used an experimental design in which they cleared large patches of pine forest from five areas. The central cleared area served as the source of dispersers. The four remaining cleared patches were (1) a rectangular unconnected patch, (2) a rectangular patch connected to the central patch with a cleared path that served as a corridor, (3) two rectangular patches with wings (patches with corridors that did not connect to other patches). The researchers were interested in the importance of habitat corridors to the movement of seeds, pollen, and butterflies between central and peripheral habitat patches. What was the purpose of planting male winterberry plants in central patches and female winterberry plants in peripheral patches? Based on the results, what would you conclude about the importance of habitat corridors?

Question 57

According to an ideal free distribution, individual organisms would be expected to move into low-quality habitat

A) when the quality of the low-quality habitat increases to equal the high-quality habitat.
B) when the per capita benefit of the low-quality habitat equals the per capita benefit of the high-quality habitat.
C) when habitat corridors open up between the two habitats.
D) when the per capita benefit of the high-quality habitat is greater than the per capita benefit of the low-quality habitat.

Question 58

Which model specifically addresses the situation in which the quality of one kind of habitat can be altered by conditions in adjacent habitats?

A) the landscape metapopulation model
B) the basic subpopulation model
C) the basic metapopulation model
D) the source-sink metapopulation model

Question 59

Ship ballast water facilitates transfer of marine invertebrates between distant oceans. This is an example of

A) a source subpopulation.
B) a sink subpopulation.
C) a dispersal limitation.
D) a habitat corridor.