Deck 9: Population Distribution and Abundance

Question 1

Some Aleutian Islands are surrounded by urchin barrens while others are surrounded by kelp forests. Which statement gives the primary explanation for these differences?

A) Kelp forest islands and urchin barren islands differ with respect to oceanic currents.
B) Kelp eat urchins, thus preventing their establishment.
C) The kelp forest islands experience a substantially warmer climate than do the urchin barren islands.
D) Grazing by urchins prevents the formation of kelp forests.

Answer 1

D

Question 2

Which statement about Duggins's urchin removal experiments is true?

A) Kelp was abundant in both the urchin-excluded and the control treatments at the start of the experiments.
B) Kelp did not become established in the control treatment.
C) Kelp did not become established in the urchin-excluded treatment.
D) Urchins died in the control treatment due to the presence of kelp.

Answer 2

B

Question 3

Refer to the figure.
Assume that the number of individuals of Laminaria is on a linear trajectory in the figure. If Duggins had sampled the kelp density 1.5 years after urchin removal, predict the approximate number of individuals of Laminaria he would have counted.

A) 20
B) 40
C) 60
D) 100

Answer 3

C

Question 4

Which statement about populations is false?

A) The distribution of a species is the geographic area where the abundance of the species is greater than zero.
B) Populations are dynamic entities that vary in size over time and space.
C) A population is a group of individuals from the same species that interact with one another within a particular area.
D) Populations are all of the species in an area that are capable of interacting.

Question 5

There are 80 swamp sparrows in a 20-hectare section of Mount Meadow. The average population density of sparrows at this site is _______ per hectare.

A) 4
B) 20
C) 80
D) 160

Question 6

If the population density of ocotillo in a desert is 15 per square kilometer, how many plants would be expected in an area that is 5 km * 3 km?

A) 15
B) 45
C) 225
D) 1,500

Question 7

Which statement about populations is false?

A) If little is known about the distance that sexually reproducing organisms or their gametes move, the area that constitutes a single population is difficult to estimate.
B) Population abundances change over time and space.
C) A population may consist of a series of patches of individuals that are isolated in space but are connected by dispersal.
D) Most organisms have similar capacities for dispersal.

Question 8

King's Lomatia (Lomatia tasmanica) is a most unusual plant. In the wild, only a single genetic individual of this shrub is known to be alive, and this colony has existed for at least 40,000 years. When a branch of this shrub falls to the ground, it sometimes establishes roots, and thus can function as a physiologically independent plant that is genetically identical to all other plants in the colony.

- What is the technical term for the single genetic individual?

A) Biotic
B) Gamete
C) Ramet
D) Genet

Question 9

King's Lomatia (Lomatia tasmanica) is a most unusual plant. In the wild, only a single genetic individual of this shrub is known to be alive, and this colony has existed for at least 40,000 years. When a branch of this shrub falls to the ground, it sometimes establishes roots, and thus can function as a physiologically independent plant that is genetically identical to all other plants in the colony.

- Which term refers to a clone that is a physiologically independent plant?

A) Biotic
B) Gamete
C) Ramet
D) Genet

Question 10

An evolutionary ecologist is studying the evolutionary change in populations of lizards that reproduce via parthenogenesis. How do these individuals form?

A) Budding
B) Apomixis
C) Horizontal spread
D) Random sexual mating

Question 11

Suppose that two species of rabbits inhabit an area. Which technique would provide estimates of their relative population densities, as opposed to estimates of their absolute densities?

A) Comparisons of area counts
B) Mark-release studies
C) Comparisons of the number of tracks made by each species
D) Quadrat sampling

Question 12

Area-based methods often make use of sampling areas of a defined size called

A) GARPs.
B) quadrats.
C) transects.
D) ramets.

Question 13

A researcher who is interested in the number of individuals in a population of butterflies and their movement patterns would most likely use which method?

A) Area-based counts
B) Point sampling
C) Line transects
D) Mark-recapture

Question 14

Point sampling is a type of

A) area-based count.
B) distance method.
C) detection function.
D) mark-recapture study.

Question 15

Suppose that a team of biologists wishes to estimate the population numbers of endangered lizards by means of line transects. Since distant lizards are difficult to see, the biologists will most likely use which method?

A) Niche modeling
B) Mark-recapture
C) Area-based counts
D) A detection function

Question 16

In a mark-recapture study to estimate the size of a rodent population, researchers catch and mark 180 individuals. Two days later, they again capture a number of rodents and find that 40% of the individuals are marked. Assuming that there have been no births, deaths, or migrations, the estimated size of the population is

A) 360.
B) 450.
C) 600.
D) 720.

Question 17

An entomology research team interested in controlling the spread of winter moths, an insect pest in the northeastern United States, samples a 150-square-meter patch of woodland with four quadrats of 1 meter by 1 meter each. In quadrats A, B, C, and D, respectively, 10, 20, 35, and 15 individual winter moths are found. What is the best estimate for the total number of winter moths in that patch of woodland?

A) 80
B) 2,000
C) 3,000
D) 8,000

Question 18

Individuals of a plant species are counted in five transects that are each 2  2 meters. In these transects, 8, 15, 19, 27, and 31 plants are found. What is the density per square meter of this species?

A) 5
B) 10
C) 15
D) 20

Question 19

A researcher studying apple maggot flies marks 180 flies in an orchid in Michigan. The next day, she collects 70 flies and finds that 14 are marked. If the assumptions of the mark-recapture method are met, what is the best estimate for the number of apple maggot flies in that orchid?

A) 180
B) 900
C) 980
D) 1,800

Question 20

Which statement is not an assumption of the mark-recapture method of estimating population size?

A) No individuals are born between the first and second captures.
B) No individuals die between the first and second captures.
C) Individuals do not move into or out of the study site between the first and second captures.
D) All marked individuals must be recaptured as well as additional unmarked individuals for accurate estimates.

Question 21

Which strategy often improves the accuracy of estimates of population size based on area-based counts?

A) Using as many quadrats as possible
B) Using population modeling to improve the accuracy of counts within a quadrat
C) Placing quadrats at the most populous locations throughout the study area
D) Using as short of line transect as possible

Question 22

Individuals of a plant species are counted in four transects that are each 2 * 3 meters. In these transects, 6, 15, 18, and 33 are found. What is the density per square meter of this species?

A) 2
B) 3
C) 6
D) 18

Question 23

Place a species distribution in order from smallest to largest.

A) Population < Metapopulation < Geographic range
B) Metapopulation < Population < Geographic range
C) Geographic range < Population < Metapopulation
D) Geographic range < Metapopulation < Population

Question 24

Which principle is best illustrated by Erickson's studies of the shrub Clematis fremontii?

A) In efforts to protect a species, one needs to consider the areas occupied by the species at all life stages.
B) Individual behavior can affect dispersion within populations.
C) Population distributions can be patchy at several levels of spatial scale.
D) Population distribution is usually patchy only at a single level of spatial scale.

Question 25

Which of the following best describes the most frequent dispersion pattern of the shrub Clematis fremontii in glades?

A) Random
B) Diapausing
C) Regular
D) Clumped

Question 26

Which population dispersion pattern is most commonly observed while conducting field surveys?

A) Regular
B) Clumped
C) Genet
D) Random

Question 27

In some trees and shrubs, competition among seedlings causes individuals to be spaced relatively evenly throughout the habitat. These plants exhibit a _______ type of dispersion pattern.

A) regular
B) ramet
C) clumped
D) random

Question 28

In some worm species, the actions of individual worms make the soil more hospitable to other members of the species. Such a phenomenon would tend to encourage which dispersion pattern?

A) Regular
B) Clumped
C) Genet
D) Random

Question 29

In the Seychelles warbler, territorial behavior would favor a _______ population dispersion pattern, and cooperative breeding would favor a _______ population dispersion pattern.

A) clumped; clumped
B) clumped; regular
C) regular; clumped
D) regular; regular

Question 30

Only a small proportion of the world's species are found on each individual continent. Which organism is an exception and has a widespread distribution across most continents?

A) Monarch butterfly
B) Barnacle (Semibalanus balanoides)
C) Norway rat
D) Heathlands

Question 31

Adult monarch butterflies overwinter

A) eastern North America.
B) in mountains west of Mexico City.
C) in the Everglades in Florida.
D) in the Dorset heathlands.

Question 32

Refer to the figure.
Based on the figure, which statement about the red kangaroo range throughout Australia is true?

A) The highest population of red kangaroo is located along the coastline of Australia.
B) Red kangaroos were surveyed along the western coastline of Australia but not the eastern coastline.
C) Red kangaroos were regularly distributed throughout central Australia.
D) There are three areas of Australia that have red kangaroo populations greater than 5-10 kangaroos/km².

Question 33

Which of the following is not an abiotic feature of the environment?

A) The salinity of the soil
B) The amount of sunlight the soil receives
C) The density of earthworms present in the soil
D) The salt content of sea mist

Question 34

Which of the following is the primary factor limiting the distribution of saguaro cacti in Arizona?

A) High temperatures
B) Low temperatures
C) Precipitation
D) Herbivores

Question 35

Which statement about Opuntia stricta is false?

A) It is native to Australia.
B) It was a pest species in Australia.
C) Introducing a moth that feeds on Opuntia stricta led to the decline of both the abundance and distribution of this cactus.
D) The distribution of this cactus in Australia was checked via biotic factors.

Question 36

A powerful ice storm in 1998 felled a large proportion of trees across much of northern New England, New York State, and southeast Canada. Although the storm led to declines in abundance for many species of birds, it created opportunities for other bird species. With regard to its effects on the abundance of bird species, the 1998 storm would be considered a

A) biotic feature of the environment.
B) facilitator.
C) disturbance event.
D) dispersal event.

Question 37

Which statement about disturbances is true?

A) All abiotic events are disturbances.
B) All disturbances are abiotic events.
C) All biotic events are disturbances.
D) Disturbances are only important in hurricane zones.

Question 38

Which of the following best explains why the mammal families in the Philippines are more similar to those in Africa than to those in New Guinea?

A) Continental drift
B) Biotic features of the environment
C) Africa's closer proximity to the Philippines
D) High dispersal rates

Question 39

Which statement about polar bears is true?

A) The evolutionary distribution of polar bears shows they once lived in Antarctica.
B) Continental drift can explain how polar bears migrated from Antarctica to the Artic.
C) Geographic distribution of polar bears is limited to the Artic because they cannot pass through warm tropical regions.
D) Polar bears' geographic distribution follows their preferred food source of penguins.

Question 40

Which type of mammals would you most likely find on a small oceanic island that is 2,000 kilometers away from any other land mass and has not been colonized by humans?

A) Wild pigs
B) Horses
C) Bats
D) Kangaroos

Question 41

_______ is the seasonal roundtrip movement of populations.

A) Migration
B) Habitat dispersal
C) Dispersal limitation
D) Disturbance

Question 42

Refer to the figure.
Based on the figure, what is the most popular winter breeding ground for humpback whales?

A) Philippines
B) Hawaii
C) Russia
D) Alaska

Question 43

Refer to the table.
Ecologists have been monitoring three metapopulations of butterflies. According to Levins's metapopulation model, which population(s) in the table would be expected to persist for a long time?

A) Population A only
B) Population B only
C) Population C only
D) Populations A and B

Question 44

Which statement does not represent an assumption of the Levins's model of metapopulation dynamics?

A) All patches have an equal opportunity to receive colonists.
B) A very large number of identical habitat patches exist.
C) The spatial arrangement of patches determines the rate at which patches will receive colonists.
D) All patches have the same probability of extinction.

Question 45

In a metapopulation, why does the colonization rate decrease as p becomes very large?

A) Extinction rates are higher.
B) There are few empty patches available for colonization.
C) Patches are exactly the same.
D) Patches are far away from each other.

Question 46

According only to the specifics of Levins's metapopulation model, which variable is important in determining whether a metapopulation can persist for a long time?

A) The spatial arrangement of patches
B) The colonization and extinction rate of patches
C) The distance to new habitats
D) The elevation of a patch

Question 47

Which of the following can cause the population of a previously nondispersed species to develop a metapopulation structure?

A) Genetic drift
B) Demographic stochasticity
C) Environmental stochasticity
D) Habitat fragmentation

Question 48

Which principle is illustrated by Lande's theoretical work with spotted owls?

A) If the availability of suitable habitat for a species goes below a critical threshold, the entire metapopulation will collapse.
B) Delay of abiotic shuffling can cause population cycles.
C) Metapopulations do not vary based on suitable habitat.
D) Introducing a small population of competitors helps keep metapopulations connected.

Question 49

In a metapopulation setting, habitat fragmentation generally causes the _______ rate to increase and _______ to decrease.

A) colonization; the extinction rate
B) colonization; environmental stochasticity
C) extinction; the colonization rate
D) extinction; genetic drift

Question 50

Which of the following is a violation of Levins's theoretical conception of a metapopulation that is often seen in a real metapopulation?

A) Demographic stochasticity
B) Genetic drift
C) Isolation by distance
D) Bottom-up control

Question 51

Which statement about Thomas and Jones's work on skipper butterflies is false?

A) The probability of extinction was higher for populations in small patches than for those in large patches.
B) The probability of colonization was higher for small patches than for large patches.
C) Patches far from another occupied patch had a lower probability of colonization than patches near another occupied patch did.
D) Population size affected the chance of colonization.

Question 52

Which negative effect can habitat fragmentation have on a metapopulation?

A) It can make patches smaller, thus increasing the patch extinction rate.
B) It can make patches more connected, thus increasing the patch colonization rate.
C) It can lead to dampened oscillations within patches.
D) It can isolate predators, preventing them from preying on the species of interest.

Question 53

Which statement about the Aleutian Island community is true?

A) Without kelp, sea urchins in this community could not persist for long periods of time.
B) Otters, which eat large quantities of food, like urchins as a source of food.
C) By the end of the nineteenth century, otters had been hunted to near extinction, but their population abundances increased throughout much of the twentieth century.
D) Both b and c

Question 54

Estes and his colleagues speculate that the decline in otters during the 1990s was due to a(n)

A) sudden increase in the numbers of urchins.
B) switch in the predation patterns of killer whales (orcas) to include more otters.
C) decrease in kelp forests due to global warming.
D) infection by hantavirus.

Question 55

Refer to the figure.
What was the otter abundance, reported as the percentage of maximum abundance, on Amchitka Island in 1993?

A) 30
B) 40
C) 60
D) 100

Question 56

Refer to the figure.
From 1950 to 2010, the average sea temperature has _______ approximately _______^oC.

A) decreased; 10
B) increased; 10
C) decreased; 1
D) increased; 1

Question 57

You are studying a type of tree that grows in dense groups made up of many individuals. These groups are generally separated by quite some distance, so each group is relatively isolated from the others. What are three possible factors that might cause this patchy distribution, and what kinds of data would you collect to determine the factor that is responsible for the dispersion you observe?

Question 58

A researcher is asked to determine the population size of redwood trees after a fire. They randomly take 5 aerial photos, each of which represents 1 km². The total area burned by the fire was 200 km². The researcher identifies 30, 2, 42, 22, and 104 redwood trees in the photos.Answer the following questions:
(a) What is the population size of redwood trees in the burn area?
(b) When looking at the data, there is one high and one low outlier. What could cause the numbers to be so different in these two photos?
(c) How could you confirm that your estimated population size is accurate?

Question 59

Refer to the figure.


- Based on the figure, describe the geographic range of the humpback whale.

Question 60

Refer to the figure.


-Based on the figure, what type of dispersion pattern best describes the location of individuals during the summer breeding season and what type best fits the location of individuals during winter?

Question 61

The giant panda is listed as vulnerable by IUCN. Suitable panda habitat is usually between 5,000 and 10,000 feet in elevation with a cool wet climate. How could a species distribution model be used to help save the giant panda from extinction?

Question 62

Imagine two small, isolated tropical islands located far from the mainland that are similar in size and physical characteristics. Although the islands have been habitable for millions of years, a small population of frogs occupies only one of the islands, having appeared there 30 years previously. What are two possible reasons why the frogs colonized the one island, and only relatively recently? What factor does not appear to have prevented them from colonizing the other island?

Question 63

Refer to the figure.
The distribution of S. balanoides stops at about 51^oN. Global warming has caused ocean temperatures to increase. As water temperatures continue to rise, what will be the effect on the distribution of S. balanoides?

Question 64

Suppose two populations are very isolated from one another, with several barriers to dispersal. Could these two populations be considered part of the same metapopulation? Why or why not?

Question 65

Roadways across the world have fragmented many habitats. Animals such as deer and boars cross roadways for many reasons, some of which include: to reach food and water sources, locate mates, or during migrations. This can result in fatal collisions between wildlife and humans. Wildlife managers and highway designers are increasingly building wildlife bridges and ecoducts to minimize wildlife and human collisions. Explain the role wildlife bridges and ecoducts play in the metapopulation concept.

Question 66

The population density of ground crickets at Oldmill Farm is about 15 per square meter. Assuming that the crickets are randomly distributed, about how many crickets would you expect to find in a rectangular section of land that is 6 meters * 2 meters?

A) 12
B) 15
C) 120
D) 180

Question 67

The size of a population of beavers in a 5 * 5 kilometer area is 675. What is the population density (in individuals per square km)?

A) 13
B) 27
C) 65
D) 165

Question 68

Some animals (e.g., whiptail lizards) and plants (e.g., strawberries) form clones of genetically identical, but physiologically independent (or potentially independent) and distinct, individuals. These independent members of a clone are called

A) ramets.
B) obelia.
C) genets.
D) gametes.

Question 69

In a mark-recapture study to estimate the size of a rodent population, researchers catch and mark 30 individuals. Two days later, they again capture a number of rodents and find that 20% of the individuals are marked. Assuming no births, deaths, or migrations, what is the estimated size of the population?

A) 60
B) 90
C) 150
D) 300

Question 70

A detection function is most likely to be used in

A) an area-based count.
B) distance methods.
C) a mark-recapture study.
D) a niche model.

Question 71

What factor is most responsible for limiting the distribution of the perennial Clematis fremontii within the state of Missouri?

A) Herbivores
B) Rainfall
C) High temperature
D) The presence of glades

Question 72

Which species will most likely exhibit a regular or nearly regular pattern of dispersion?

A) A species that competes for a limiting resource that is equally distributed in space
B) A species whose habitat is patchily distributed
C) A species with short dispersal distances
D) A species in which individuals are positioned at locations selected at random

Question 73

Which statement about species geographic ranges is true?

A) Endemic species are located throughout the world.
B) Geographic ranges only need to include one life stage.
C) Most species can be found throughout Earth.
D) Species distribution models aid scientists and policymakers in making decisions about species protection plans.

Question 74

Which of the following is not a biotic feature of the environment that can limit an organism's distribution or abundance?

A) Parasites
B) Competitors
C) Predators
D) Rainfall

Question 75

Which statement about the influence of evolutionary and geologic history on species distribution and abundance is true?

A) Evolutionary history cannot influence where an organism exists today.
B) Geological history influences distribution of suitable habitat and thus influences where an organism exists today.
C) Geological history cannot influence dispersal of populations.
D) Evolutionary history can only influence the abundance of a population if the species evolved within the last 10,000 years.

Question 76

What is the most likely reason that polar bears are found in the Arctic but not in Antarctica?

A) Antarctica does not provide a suitable habitat for polar bears.
B) Polar bears, which were derived from brown bears that lived in the Northern Hemisphere, are unable to travel long distances.
C) Polar bears, which were derived from brown bears that lived in the Northern Hemisphere, can migrate long distances, but they are either unable or unwilling to travel across tropical areas that lie between the Arctic and Antarctica.
D) Continental drift prevented the polar bears from going to Antarctica.

Question 77

A species limited capacity to disperse, preventing it from reaching suitable habitat, is known as

A) migration.
B) habitat dispersal.
C) dispersal limitation.
D) disturbance.

Question 78

Ecologists have been monitoring three metapopulations of sawflies. Population A has a patch colonization rate of 0.08 and a patch extinction rate of 0.11. Population B has a patch colonization rate of 0.05 and a patch extinction rate of 0.04. Population C has a patch colonization rate of 0.10 and a patch extinction rate of 0.08. According to Levins's metapopulation model, which of these populations would be expected to persist for a long time?

A) Population A only
B) Population B only
C) Population C only
D) Populations B and C

Question 79

Lande's theoretical work contributed to the listing of the northern spotted owl as a threatened species in the United States. Which threat to the owl did Lande's work identify?

A) Demographic stochasticity
B) Habitat fragmentation
C) Dampened oscillations
D) Inbreeding

Question 80

According to the work of Estes and others, an increase in _______ would lead to an increase in the abundance of urchins.

A) otters
B) glades
C) orcas
D) Opuntia stricta