Deck 20: Population Ecology

Question 1

The island of Guam traditionally has not had any snakes that prey on birds;however,brown tree snakes that prey upon birds were introduced.Use your knowledge of wolf-moose population dynamics to determine what happened to the population dynamics of birds and the new snakes on Guam.Which statement is probably one of the results of the snake introduction?

A) Because prey was abundant and few predators existed,snakes spread throughout the island.
B) Snake populations increased exponentially as they preyed upon birds that had no defenses against the predators.
C) As snake populations became very large,they reached the carrying capacity of Guam and caused bird populations to crash.
D) Because bird populations crashed,one of the birds' main prey items,spiders,increased their population size.
E) All of these happened.

Answer 1

E

Question 2

By studying the data collected from Isle Royale,ecologists have discovered that a large wolf population correlates to vigorous tree growth.Which statement best explains this pattern?

A) Wolves decrease the moose population,which consumes trees as its main diet.
B) When there is a large wolf population on the island,the moose swim to the mainland.The decrease in moose allows for more tree growth.
C) The remains of moose carcasses fertilize the soil,which allows for increased tree growth.
D) all of these
E) none of these

Answer 2

A

Question 3

All of these statements can be advantages of a clumped distribution pattern EXCEPT _____.

A) it allows individuals to maximize space between them
B) it allows organisms to hunt prey more efficiently
C) it helps organisms defend themselves against predators
D) organisms can match their distribution to resource-rich areas
E) all of these are advantages of a clumped distribution pattern.

Answer 3

A

Question 4

Growth rates are _____.

A) the difference between birth and death rates in a population
B) not influenced by immigration and emigration patterns
C) positive when the birth rates are less than the death rates
D) logistic when the populations increase at a constant rate
E) none of these

Question 5

All of these statements regarding ecosystems are correct EXCEPT _____.

A) individuals,populations,and communities are all part of an ecosystem
B) an ecosystem is composed of the living and nonliving components of an environment
C) studying an ecosystem can help scientists understand individual populations
D) sunlight and water are good examples of living components of an ecosystem
E) moose and wolves are part of the Isle Royale ecosystem

Question 6

Imagine a system where a finch feeds on thistle seeds and the finch population size is linked to the productivity of the thistle,and the thistle population size is related to foraging pressure of the finch population.This is an example of population dynamics at the _____ level.

A) population
B) community
C) ecosystem
D) species
E) biosphere

Question 7

Population dynamics are influenced by birth and death rates.Which situation is NOT a factor that can cause early death for wolves on Isle Royale?

A) starvation if wolves cannot find and catch enough prey to survive
B) bone deformities causing impairments in hind leg use,probably from inbreeding
C) warmer temperatures causing tick populations that feed on wolves to increase dramatically,which causes wolves to lose blood and decreases their hunting abilities
D) warmer temperatures decreasing the frequency with which ice bridges form between Isle Royale and the mainland,which reduces the chances for immigration by new wolves that might increase the genetic diversity of the island population
E) all of these

Question 8

Ecologists often study the spatial distribution of animals.Which of these descriptions of common distribution patterns is incorrect?

A) Random: fish on a coral reef occur in small groups and alone all around the reef,and are equally likely to be anywhere on the reef.
B) Clumped: wolves cluster together in packs that generally move around together.
C) Uniform: moose are highly territorial creatures and move around an island habitat in large groups.
D) All of these examples are consistent with their descriptions.
E) None of these examples is consistent with its description.

Question 9

Carrying capacity is NOT the point _____.

A) at which a population reaches the maximum number of individuals that an environment can support
B) around which a population's size tends to fluctuate
C) where additional resources are available only to individuals that immigrate into the population
D) where available resources are being fully exploited by the population
E) all of these

Question 10

Once the carrying capacity of an environment is reached,the population generally _____.

A) cannot continue growing exponentially
B) may fluctuate by slightly exceeding the carrying capacity,and then dropping below it
C) may experience cycles of "boom and bust"
D) all of these
E) none of these

Question 11

Why are truly random distributions rare in nature?

A) Individuals of a particular species often need certain types of conditions to survive and grow,so more individuals are found in these areas.
B) Resources are unevenly distributed across most landscapes.
C) Many species have social behaviors that promote clusters of individuals for increasing foraging success or for predator avoidance.
D) none of these
E) all of these

Question 12

Ecologists study organisms at a number of levels with different numbers of components.Which sequence correctly orders these levels,from smallest to largest?

A) individual,population,community,ecosystem
B) population,individual,community,ecosystem
C) community,individual,population,ecosystem
D) ecosystem,population,community,individual
E) none of these

Question 13

Which event or condition is a density-independent factor that could influence population growth?

A) a disease that spreads through direct physical contact
B) a new predator that moves into an area with hunting tactics that the prey species are not adapted to avoid
C) a volcanic eruption that covers an island in a layer of lava
D) a sudden decrease in the food supply due to usually dry conditions
E) all of these

Question 14

Which phrase is NOT a biotic factor affecting population growth of moose on Isle Royale?

A) summer temperatures
B) food availability
C) wolf population size
D) tick population growth
E) infectious disease

Question 15

How have warmer-than-normal climatic conditions affected moose populations on Isle Royale?

A) Moose escaped the heat by resting in the shade,but then had less time for eating,which resulted in thinner moose that were not as prepared to survive winter temperatures.
B) An increase in the tick population has resulted in weight loss for the moose,which increased their death rate.
C) Tick populations have grown and they have fed on the moose,which resulted in blood loss and higher death rates for moose.
D) none of these
E) all of these

Question 16

Which ecological definition is incorrect?

A) A population is a group of individuals of the same species living in the same region.
B) An ecosystem consists of individuals,populations,and communities.
C) An individual is a single organism of a particular species.
D) A community is made up of biotic and nonliving components.
E) none of these

Question 17

An ecosystem ecologist might study

A) plant populations.
B) herbivores that eat the plants.
C) predators in the population.
D) the impact of precipitation patterns on the plant populations.
E) All of the answers are items an ecosystem ecologist might study.

Question 18

When moose first arrived on Isle Royale and found a habitat without predators,the moose population _____.

A) grew exponentially,and then crashed due to lack of food.
B) re-grew after a starvation period that allowed the vegetation to recover.
C) could be categorized as going through a cycle of "boom and bust" population dynamics.
D) was not regulated by predator-prey interactions.
E) all of these

Question 19

Which statement is true of distribution patterns in nature?

A) Four main types of distribution exist.
B) Uniform distribution allows individual organisms to maximize space between them.
C) Species can always be categorized into one distinct type of distribution,and populations never vary from this categorization.
D) Clumped distribution has no advantages and is rarely observed in nature.
E) all of these

Question 20

Which of these is NOT an example of something that ecologists would generally study?

A) how predators,such as sharks,affect the population of prey,such as fish
B) how the mitochondria of a mouse function in its cells
C) how the Amazon tropical rain forest is affected by its plants,animals,weather,and geology
D) how one species of butterfly forages and reproduces in its habitat
E) the population dynamics of one species of sea urchin

Question 21

Which of the following would cause a population to grow?

A) identical increases in both the birth rate and the death rate of a population
B) a decrease in the birth rate and an increase in the death rate of a population
C) an increase in the birth rate and a decrease in the death rate of a population
D) an increase in the birth rate and a larger increase in the death rate of a population
E) identical decreases in the birth rate and the death rate of the population

Question 22

All of the polar bears,seals,fish species,whales,seabirds,and the Aleut people in the Aleutian Islands make up a(n)______.

A) island ecosystem
B) island system population
C) island biogeographic unit
D) population
E) community

Question 23

The term _______ describes the interacting populations (e.g. ,moose and ticks)within an ecosystem.

A) competition
B) community
C) niche
D) habitat
E) predator-prey relationships

Question 24

The term _______ describes all interacting species,such as moose,ticks,and wolves,as well as their surrounding environment of trees,vegetation,and climate.

A) habitat
B) community
C) biosphere
D) ecosystem
E) biome

Question 25

The geographic distribution of a population is influenced by all of the following,EXCEPT

A) resources.
B) behavior.
C) number of young born.
D) predator avoidance.
E) environment.

Question 26

Which of the following is a density-dependent factor influencing population growth?

A) elevated temperature
B) prolonged winters
C) a viral disease
D) a devastating forest fire
E) All of the answers are correct.

Question 27

Butterflies eat flower nectar and birds eat butterflies.The butterflies,flowers,and birds constitute a(n)

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

Question 28

All of the gray wolves found in Yellowstone Park constitute a _____.

A) community
B) pack
C) family
D) population
E) species

Question 29

A community is composed of _____.

A) many individuals
B) many populations
C) one or more ecosystems
D) two or more species of plants
E) all of the individuals in two or more species

Question 30

A report that documents all the species (plants and animals)in an area but does not include the environment describes

A) the ecological niche of each species.
B) a habitat.
C) a community.
D) a population.
E) a biome.

Question 31

Which would NOT be examined in the study of a community?

A) prey population
B) predator population
C) trees and vegetation
D) rainfall and drought
E) All of the answers are correct.

Question 32

A researcher who investigates how flooding affects the different populations on an island is most interested in which level of organization?

A) ecosystem
B) community
C) biome
D) individual
E) biosphere

Question 33

Why do ecologists count representative samples of a population and not the total population under study?

A) to get a precise number
B) because it is impractical to count all the members of the population
C) because it is the way that ecologists study ecosystems
D) to get an estimate before counting the whole population
E) because a representative sample more accurately reflects the carrying capacity

Question 34

The ocean,sand,rocks,plants,seagulls,and invertebrates represent a(n)

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

Question 35

Put the following in order from simplest to most complex.

A) individual $\gamma$ ecosystem $\gamma$ community $\gamma$ population
B) individual $\gamma$ population $\gamma$ ecosystem $\gamma$ community
C) individual $\gamma$ population $\gamma$ community $\gamma$ ecosystem
D) individual $\gamma$ community $\gamma$ population $\gamma$ ecosystem
E) individual $\gamma$ community $\gamma$ ecosystem $\gamma$ population

Question 36

Which of the following statements describes an example of population growth?

A) The average weight of Americans has increased substantially in the past decade.
B) Tropical fish have been found in waters more northerly than their usual habitat.
C) The number of people in a town has increased by 25% in the past 5 years.
D) The number of butterflies in a region has stayed the same from 1950 to 2010.
E) All of the answers are correct.

Question 37

Ocean fish demonstrate which distribution pattern?

A) random
B) uniform
C) clumped
D) irregular
E) asymmetric

Question 38

In predator-prey relationships,scientists are interested in which level of organization?

A) niches
B) an individual
C) a population
D) a community
E) an ecosystem

Question 39

A report based on the interactions of wolves,moose,ticks,and trees on Isle Royale describes a(n)______.

A) population
B) community
C) habitat
D) biome
E) ecosystem

Question 40

The total number of wolves inhabiting Isle Royale is defined as a _____.

A) species
B) community
C) population
D) group
E) pack

Question 41

A species of highly territorial individuals with limited territory and a large population is most likely to have a ____ distribution.

A) random
B) linear
C) spherical
D) clumped
E) uniform

Question 42

You have a population of 1000 individuals that is increasing at a growth rate of 10% per year.What will the population be in 5 years?

A) 1500
B) 1610
C) 1250
D) 1110
E) 2000

Question 43

A plant with wind-dispersed seeds is most likely to grow in a ____ distribution.

A) random
B) linear
C) spherical
D) clumped
E) uniform

Question 44

A population limited by environmental factors would be an example of

A) logistic growth.
B) exponential growth.
C) logarithmic growth.
D) arithmetic growth.
E) linear growth.

Question 45

Schools of fish in a reef are an example of a ____ distribution.

A) random
B) linear
C) spherical
D) clumped
E) uniform

Question 46

Which of the following represents exponential population growth?

A) 100 $\rightarrow$ 110 $\rightarrow$ 120 $\rightarrow$ 130 $\rightarrow$ 140
B) 100 $\rightarrow$ 110 $\rightarrow$ 130 $\rightarrow$ 160 $\rightarrow$ 200
C) 100 $\rightarrow$ 110 $\rightarrow$ 121 $\rightarrow$ 133 $\rightarrow$ 146
D) 100 $\rightarrow$ 150 $\rightarrow$ 200 $\rightarrow$ 250 $\rightarrow$ 300
E) 100 $\rightarrow$ 150 $\rightarrow$ 250 $\rightarrow$ 450 $\rightarrow$ 850

Question 47

In a geographically isolated habitat,DNA analysis of a population can document

A) DNA inbreeding.
B) loss of genetic diversity.
C) identification of individuals by DNA profiling.
D) changes in allele frequency of a gene.
E) All of the answers are correct.

Question 48

Which population distribution pattern is encountered most often by ecologists?

A) random
B) clumped
C) uniform
D) irregular
E) asymmetric

Question 49

Which of the following can be used to monitor the health of a wild animal?

A) scat
B) bones
C) urine
D) DNA
E) All of the answers are correct.

Question 50

Scat is _____.

A) a parasite found on wolves
B) a species of mite
C) feces
D) urine
E) blood

Question 51

When a population reaches its carrying capacity,its growth rate will

A) increase exponentially.
B) increase arithmetically.
C) slow and remain near zero.
D) decrease slowly.
E) decrease rapidly.

Question 52

A flock of birds represents a _________ distribution pattern,whereas birds on a power line with six inches of space between each bird represents a _________ distribution pattern.

A) uniform;random
B) clumped;random
C) random;uniform
D) clumped;uniform
E) random;clumped

Question 53

Place the population distribution pattern in order from most to least frequently encountered by ecologists.

A) random,asymmetric,and uniform
B) clumped,random,and uniform
C) clumped,uniform,and random
D) uniform,asymmetric,and clumped
E) asymmetric,clumped,and random

Question 54

Which population would most likely resemble a random distribution pattern?

A) humans in North America
B) penguins nesting in Antarctica
C) wolves in Isle Royale
D) termites in a rainforest
E) understory plants in a tropical rainforest

Question 55

The growth rate of a population is calculated from the ___ for that population.

A) carrying capacity
B) difference between births and deaths
C) birth rate
D) death rate
E) birth rate and the carrying capacity

Question 56

Most species on the planet have a _____ distribution.

A) random
B) linear
C) spherical
D) clumped
E) uniform

Question 57

Which behavior would most likely result in a uniform distribution pattern?

A) migration
B) defensive strategies
C) predator avoidance
D) territorial and nesting behaviors in birds
E) social network of bees

Question 58

Which of these would NOT be useful in assessing a population's health?

A) urine
B) bone remains
C) fecal remains
D) radio transmitters
E) blood spatter

Question 59

What information could be obtained from wolf scat?

A) DNA profiles
B) vegetation preference
C) presence of arthritis
D) amount of urea
E) time since last meal

Question 60

The best example of exponential population growth would be an increase of _____ per generation.

A) 10 individuals
B) 10%
C) 10X (tenfold)
D) a variable rate,from 1.5X to 10X
E) All of the answers are correct.

Question 61

A few years after a predator species population increases,the ____.

A) predator population will increase
B) prey population will decrease
C) predator population will decrease
D) predator population will exceed carrying capacity
E) prey population will exceed carrying capacity

Question 62

In the absence of a predator species,herbivores like moose _____.

A) will continue to have an exponential growth rate
B) will almost always die off because of the presence of density-dependent diseases
C) may exceed carrying capacity and have a fast die-off
D) will evolve to no longer require predators to balance their population size
E) may eventually become omnivores

Question 63

The difference between birth rate and death rate is known as

A) the survival rate.
B) the logistic rate.
C) the growth rate.
D) the differential factor.
E) the survivorship curve.

Question 64

A decrease in natural resources will ____.

A) increase the carrying capacity
B) stimulate an increase in reproductive rate
C) cause a reduction in habitat area
D) decrease the carrying capacity
E) eliminate the population

Question 65

The prey species on Isle Royale is the

A) moose.
B) wolf.
C) fox.
D) ravens.
E) caribou.

Question 66

The rate of natural increase approximates zero when carrying capacity is reached and

A) birth rate < death rate.
B) birth rate $\approx$ death rate.
C) birth rate > death rate.
D) the death rate falls to zero.
E) the birth rate falls to zero.

Question 67

Which of the following BEST describes the growth curves of predator and prey?

A) zero growth rate for each population
B) exponential growth for both until carrying capacity is reached
C) interdependent cycles of boom and bust or hills and valleys
D) logistic growth until carrying capacity is reached
E) a leveling off of growth when the natural increase is zero

Question 68

A few years after a predator species population decreases,the ____.

A) predator population will increase
B) prey population must decrease
C) predator population will decrease
D) predator population will exceed carrying capacity
E) prey population will increase

Question 69

A few years after a prey species population increases,the ____.

A) predator population will increase
B) prey population must decrease
C) predator population will decrease
D) predator population will exceed carrying capacity
E) prey population will exceed carrying capacity

Question 70

From studies of predator/prey relationships,it could be predicted that an increase of zebra on a savannah would be followed by a subsequent

A) decrease in herbivores.
B) decrease in gazelles.
C) increase in herbivores.
D) increase in lions.
E) decrease in lions.

Question 71

When discussing human population trends,birth rate is often expressed as a number called the total fertility rate (TFR).The TFR is the number of children an average woman in the country has in her lifetime.The number of children a couple must have to replace themselves in the population is called the total replacement rate (TRR).TRR can be used a lot like death rate when calculating population trends.As a worldwide average,each couple must have 2.1 children to replace themselves (the extra 0.1 is the result of infant mortality).
TFR and TRR are given below for several countries.Which country has a decreasing population size?

A) TFR = 2.1,TRR = 2.1
B) TFR = 5,TRR = 4
C) TFR = 3,TRR = 3
D) TFR = 7,TRR = 9
E) TFR = 2.2,TRR = 2.1

Question 72

An increase in predator numbers is usually followed by a subsequent

A) decrease in predator numbers.
B) decrease in prey numbers.
C) increase in prey numbers.
D) extinction of prey.
E) extinction of predators.

Question 73

The predator species on Isle Royale is the

A) moose.
B) wolf.
C) plants.
D) ravens.
E) caribou.

Question 74

Which of the following most accurately describes the population cycles of moose and wolves on Isle Royale?

A) Moose and wolf populations stay at carrying capacity.
B) Moose populations stay at carrying capacity,while wolf populations rise and fall.
C) Moose populations rise and fall,while wolf populations stay at carrying capacity.
D) Moose and wolf populations rise and fall at the same time.
E) Moose and wolf populations rise and fall,but wolf populations peak a few years after the moose population peaks.

Question 75

Carrying capacity is the _____.

A) number of individuals in a given area
B) total biomass of a given area
C) total plant biomass of a given area
D) total plant biomass minus the animal biomass in a given area
E) maximum number of individuals of a population that an area can support

Question 76

How do the population curves of predator and prey relate to each other?

A) A decrease in prey is followed by an increase in predators.
B) An increase in the prey population is followed by an increase in predators.
C) An increase in the predator population is followed by an increase in prey.
D) An increase in the prey population is followed by a decrease in predators.
E) Both populations level off once carrying capacity is reached.

Question 77

A population's growth rate depends on

A) birth rate.
B) death rate.
C) immigration.
D) emigration.
E) All of the answers are correct.

Question 78

Which of the following conditions indicates that a population is living at its carrying capacity?

A) birth rate = death rate;immigration = emigration
B) birth rate = death rate;immigration > emigration
C) birth rate > death rate;immigration > emigration
D) birth rate > death rate;emigration > immigration
E) birth rate > death rate;immigration = emigration

Question 79

Which of the following conditions would lead to the fastest population growth?

A) birth rate = death rate;immigration = emigration
B) birth rate = death rate;immigration > emigration
C) birth rate > death rate;immigration > emigration
D) birth rate > death rate;emigration > immigration
E) birth rate > death rate;immigration = emigration

Question 80

A few years after a prey species population decreases,the _____.

A) predator population will increase
B) prey population must decrease
C) predator population will decrease
D) predator population will exceed carrying capacity
E) prey population will exceed carrying capacity