Ecology exam 2

You are hired by the U.S. Fish and Wildlife Service to determine the density of bullfrogs in a series of five perfectly square ponds. At each pond, you sample both the number of bullfrogs and the length of one side of each pond, and you record these observations in the following table: What is the average number of bullfrogs per square meter in these five ponds?

3.2

Identify scenarios in which two distantly related species would compete with one another.

- Frogs and fish prefer different insects for food, but their diets overlap when resources are lacking. - Birds build nests and spiders build webs on terminal tree branches at particular heights.

Select the statements that explain why very small and very large populations experience slow population growth under the logistic growth model.

-Small populations have fewer individuals capable of producing offspring. -Limited resources are shared among many individuals in very large populations.

Given the relationship between λ and r in the geometric and exponential growth equations, what is λ when r is 0?

1

You have recently been hired to study the age structure of a small population of a newly discovered monkey species in South America. This monkey species is unique in that the gestation period is 2 years. The number of offspring that a female will produce is directly influenced by the amount of calories she ate in the year before she got pregnant. During the past 4 years, you have recorded the following age structure data for this monkey population by sampling the population each spring: In which year did reproductively mature females consume an unusually high number of calories?

2008

Compounds produced by plants that have toxic effects on herbivores are known as _____.

alkaloids

What is NOT true about density-dependent factors?

always positive

Select the order of steps in a mark‐recapture survey.

Capture a sample of individuals, mark the individuals, release the individuals, wait for the individuals to disperse, capture a second set of individuals.

Warning colors, such as those displayed by monarch butterflies, are a defense strategy also known as _____.

aposematism

The brain worm parasite is commonly found in white-tailed deer with little impact, but can be transmitted via intermediary hosts to moose with often fatal consequences. This is an example of

apparent competition.

One reason organisms with large body sizes have higher survival rates is because they _____.

are better at maintaining homeostasis in the face of unfavorable environmental changes

From the perspective of natural selection, alarm calls as a behavioral defense should be selected for if the recipients of the warning call

are related to the maker (initiator) of the call.

You are asked by a lake management group to estimate the density of an invasive submerged aquatic plant per square meter along the bottom of a very large lake. You need to know the approximate number of shoots per meter squared in the lake to calculate the appropriate concentration of an herbicide to control the plants. As you study the lake, you determine that the invasive plant occupies a large portion of the bottom of the lake, and where it occurs, it always grows in approximately the same high density. Because the water is clear, you can use aerial measurements to estimate the total lake-bottom area occupied by the plant. What would be the best type of survey for determining the approximate density of plant shoots in this lake?

area-based

In what situation would you expect the number of offspring per female to be the highest?

at the end of a die-off

True or false? Allelopathy is a type of interference competition that only occurs between native competitors that have a long evolutionary history of competing with one another.

False

How might a type II functional response prevent a predator from limiting the size of a large prey population?

Predators are limited to a maximum consumption rate because of the time spent handling prey, leaving less time to hunt additional prey and decrease the large population.

What is TRUE regarding populations of various taxa?

Species with higher abundances have larger geographic ranges

Why may human intervention be necessary in order for the small population of wolves on Isle Royale to survive?

The rescue effect will not occur with the decrease in ice bridge formation between the mainland and the isle.

What rule do researchers use to determine if two means are significantly different from each other in a t‑test?

The 𝑡critical‑value is equal to or smaller than the t‑value.

Explain the concept of "competition coefficients" that are used in the Lotka-Volterra competition equations.

They convert the number of individuals between the two competing species into equivalents.

How can energy reserves make a population experience delayed density dependence?

They enable the population to survive above carrying capacity.

If two species require the same limiting resource, what would you predict about their ability to coexist?

They will be unable to coexist, whether the resource is renewable or nonrenewable.

True or false? The geographic range of the emerald ash borer has expanded rapidly in the United States, largely from unintentional human assistance.

True

True or false? The ideal free distribution tells us that the persistence of populations living in low-quality habitats is dependent upon the dispersal of offspring from populations living in high-quality habitats.

True

H5N1 is an example of

an emerging infectious disease.

In a typical S-I-R model, why does the number of susceptible people decrease over time?

because the number of infected people increases

Isle Royale is an ongoing study of moose‐wolf population fluctuation. Why is this study site so useful to ecologists?

because the populations are relatively free from immigration and emigration

Mistletoe, commonly used as a holiday season decoration in North America, is classified as which of the following?

both an ectoparasite and a hemiparasite

Alterations over many generations in genotypes and phenotypes of predator and prey species in response to one another is an example of which of the following?

coevolution

In a metapopulation, the probability that any subpopulation will go extinct _____.

decreases with increasing movement of individuals between patches

If you are modeling population growth and you do NOT factor in the fact that the environment in recent years has been conducive to high birth rates and low death rates, you are using a(n) _____ model.

deterministic

A population growth model that is based on all individuals in the population having the same birth and death rates is called a

deterministic model.

The movement of individuals from one area to another is referred to as _____.

dispersal

Inhospitable habitat that keeps a population from extending into suitable habitats is called _____.

dispersal limitation

The difference between dispersal and migration is that

dispersal tends to be one directional.

A population that exceeds its carrying capacity will likely

experience a die off

For life tables, _____ is operationally defined as the number of female offspring produced per reproductive female.

fecundity

When one looks at the relationship between the density of meadow voles in a field and their rate of consumption by red-tailed hawks (which feed on meadow voles) one is looking at the red-tailed hawk's

functional response.

The geometric growth model is most useful for species that _____.

have distinct breeding periods during the year.

If you were trying to determine the abundance of a large migratory songbird population in Connecticut, what would be the best approach?

mark-recapture survey

Which species would you expect to have the highest density?

mice

Parasites outside their native range are often

more deadly

The competitive exclusion principle states that _____.

no two organisms can coexist indefinitely when they are in competition for the same resources

In the Lotka-Volterra model for prey populations, which of the following terms represents the exponential growth of the prey population?

rN

The rescue effect

refers to the dispersal between source and sink populations.

Which disease is least likely caused by a bacterial parasite?

smallpox

The S-I-R model does not necessarily follow the traditional Lotka‐Volterra Model for predator and prey because

some pathogens do not attack a single host species.

What mechanisms could cause evenly spaced distributions of individuals within populations?

territorial animals

Which model includes consideration of the quality of the surrounding matrix?

the landscape model

Which factors determine the equilibrium population size of predators during predator-prey population cycles?

the mortality rate of the predator and the prey capture rate

Classify predator responses to changes in prey population size as either numerical or functional. Numerical response

- A sharp rise in the grasshopper population size one summer results in a twofold increase in blue jay offspring the following spring. - Individual sea lions immigrate into a different population because of a large grouping of herring available in the new habitat.

Classify predator responses to changes in prey population size as either numerical or functional. Functional response

- As the abundance of acorns increases, each gray squirrel spends a greater amount of time cracking open shells to feed. - As the population density of mice decreases, the prairie falcon begins consuming chipmunks as its primary prey. Functional response - As the size of lichen populations increases through the year, each reindeer in a herd consumes a greater mass of lichens each day.

Classify the descriptions of organisms as examples of clustered, evenly spaced, or random dispersion patterns. Clustered dispersion

- Cattails only growing in the shallow water of a lake. - Wolves forming. a pack within a large territory. Clustered dispersion

Classify each statement as describing a cohort life table or a static life table. Static life table

- Collects data from individuals of all ages at a single time interval. - Measures differences between ages under the same conditions. -Is appropriate for mobile or long-lived organisms.

Classify each statement according to whether it applies to the exponential or geometric growth model: Exponential growth model

- Geometric growth model - assumes continuous growth over a period of time

Classify each example as a case of demographic stochasticity or environmental stochasticity. Demographic stochasticity

- In an isolated population of ten Florida panthers, all four offspring born one year are female. - The first two rat snakes accidentally released on an island are male, so no young are born.

Classify each example as a case of demographic stochasticity or environmental stochasticity. Environmental stochasticity

- Lightning strikes the tree in which an osprey is nesting, killing the chicks. - After a fire burns a forest patch, the additional sunlight and nutrients available in the burned patch allow more white pine seeds to sprout than in the unburned forest.

Determine whether the population in each scenario exhibits density independence, negative density dependence, or delayed density dependence. In dry areas, mesquite seedlings do not grow near mature mesquite trees because roots of established trees outcompete the seedlings for limited water. As food resources become scarcer, female fruit flies in a large population lay fewer eggs. After a harsh winter with little food available, a healthy herd of deer that bred in the fall produces fewer spring fawns than expected. During a summer with plentiful food, female black bears store up enough fat reserves to produce more healthy cubs than normal while denning in winter. In spring, the bear population exceeds its carrying capacity. Few bears produce offspring during the next winter. A fire sweeps through a pine forest, killing most of the new pine seedlings and injuring some of the mature trees.

- Negative density dependence - Negative density dependence - Delayed density dependence - Delayed density dependence - Density independence

Classify each statement as describing a stable population of bears or a population of bears with a stable age distribution. Stable population

- Over multiple years, the total number of bears in the population does not change as the proportion of cubs to adults decreases. - A population size holds constant from one year to the next as the proportion of cubs to adults changes.

In a life table, the survival rate (sx) describes the ___, whereas survivorship (lx) describes the___

- PROPORTION OF INDIVIDUALS THAT SURVIVE FROM ONE AGE CLASS TO THE NEXT -CUMULATIVE PROPORTION OF INDIVIDUALS THAT SURVIVE TO A CERTAIN AGE CLASS.

Classify the descriptions of organisms as examples of clustered, evenly spaced, or random dispersion patterns. Evenly spaced dispersion

- Penguins leaving a minimum distance between nests in a breeding colony.

Identify scenarios that describe an emerging infectious disease.

- Reported cases of Lyme disease in humans have increased steadily since its relatively recent recognition in 1976. - An infectious fungus observed in the black poplar tree recently appeared in the Eastern cottonwood tree. - Malaria cases have increased exponentially due to malaria's resistance to drugs and mosquitoes' resistance to pesticides.

Desert rodents and ants both depend on seeds from scrub plants as a food resource. What conditions would favor the existence of both species within the biological community?

- Rodents prefer larger seeds as a food choice, while ants tend to consume smaller seed types. - Rodents and ants inhabit different areas of the habitat based on temperature and rainfall patterns in the environment.

The American bullfrog is native to much of the eastern and central United States. Over the past 200 years, humans have repeatedly introduced bullfrogs into other areas. What conclusions can be drawn from the map of the American bullfrog's current range in the United States?

- The bullfrog lacks dispersal corridors with suitable habitat between east and west coast populations. - The bullfrog's realized niche includes its native range and much of the habitat along the west coast.

Classify each statement as describing a stable population of bears or a population of bears with a stable age distribution. Stable age distribution

- The proportion of cubs to adults remains constant in a bear population that declines in size each year. - From one year to the next, a growing population consistently has about three times as many cubs as adults.

Classify each statement as describing a cohort life table or a static life table. Cohort life table

- Tracks one group of individuals throughout their life spans. - Cannot distinguish environmental effects from differences among ages -Is a useful strategy for sessile or short-lived organisms.

In a stream ecosystem, two species of aquatic plants rely on available nitrogen and phosphorus as nutrients. Under what conditions would these two species, in competition for two nutrient resources, be prevented from coexisting?

- When one species is better able to persist at lower levels of nitrogen and phosphorus, while the other species requires high levels of both. - When both species are able to persist at equivalent levels of nitrogen and phosphorus. - When both species are able to survive at lower levels of nitrogen but require higher levels of phosphorus.

Classify the descriptions of organisms as examples of clustered, evenly spaced, or random dispersion patterns. Random dispersion

- Wind-blown pine seeds sprouting wherever they fall on a burned hillside.

Two bamboo lemur species of genus Prolemur are sympatric and rely on the same parts of the same plant species for food. If one species adapts to utilize different parts of the plant species for its food, then competition between the two species would most likely ____ Two sifaka lemur species of genus Propithecus are allopatric and rely on the same parts of the same plant species for food. If human activity displaces one species into sympatry with the other species, then competition between the two species would most likely___ Propithecus verreauxi and Lemur catta are sympatric and compete for the same food resources. Both species exhibit preference for fruits that are rare in their range. If fruit abundance suddenly increased, then competition between the two species would would most likely___

- decrease - increase - stay the same

When the intrinsic growth rate (r) of a population equals zero, the population size after one year (N1) is __ the initial population size (N0). Therefore, the annual growth rate (λ) of the population equals__

- equal to - 1

Select the population growth model for a small group of white‑tailed deer, which give birth each spring. Why is the selected model of population growth appropriate for white‑tailed deer?

- geometric growth - It models species that reproduce at discrete intervals.

Classify each statement according to whether it applies to the exponential or geometric growth model: Geometric growth model

- includes λ, the ratio of population sizes from year to year - assumes growth at specific intervals over a period of time

Classify resources as nonrenewable or renewable. Nonrenewable resources Renewable resources

- nesting sites - space - sunlight - rainfall - soil nitrates - seeds

The slope of the curve that plant ecologists refer to as the self-thinning curve is

-3/2.

Which of the following is the best example of a habitat matrix?

-An ocean surrounding islands.

Amphibians are animals that begin their lives in water or in a protective, wet, jelly‑like coating. Most amphibians also live part of their juvenile or adult lives on land. Although they have lungs, amphibians supplement their breathing through their skin. Their skin must stay minimally moist for the gas exchange to take place. What are potential dispersal barriers for North American amphibians that migrate northward due to climate change?

-Clearcut forest. -Highways. -Paved parking lots.

Why might the Isle Royale wolf population be more prone to extinction than other wolf populations?

-Ice rarely forms a travel corridor between Isle Royale and the mainland, which isolates the island wolves. -Isle Royale is only large enough to support a small population of wolves, even at the best of times.

Black‑footed ferrets were once plentiful throughout the western United States. They were nearly driven to extinction through habitat fragmentation, poisoning, and disease. Conservationists have reintroduced metapopulations of black‑footed ferrets to some parts of the ferrets' historical range. Reintroductions are in areas with prairie dog towns, because prairie dogs are the ferret's main prey. Which arguments led conservationists to reintroduce black‑footed ferrets as metapopulations instead of as isolated populations?

-If stochastic events killed off a few small populations, other black-footed ferrets would survive. -Each prairie dog town can only provide food for a small population of black-footed ferrets.

In a metapopulation, which of the following circumstances can help to keep a species from going extinct?

-Large habitat patches that are close together.

Why does an invasive species often have harmful effects on native species?

-Native species are less competitive with or have fewer defensive adaptations against an invasive species.

Identify how removing the cats from Macquarie Island affected the island's ecosystem.

-Predation on the islands' birds decreased, preventing further population drops and extinctions. -The rabbit population increased tenfold, leading to the consumption of most of the island's plants.

A plant species has defenses that make it unpalatable to most herbivores. A generalist herbivore eats a variety of other plants and seldom eats this plant. A specialist herbivore eats only the well‑defended plant species. How might the abundance of the well‑defended plant be affected differently by the generalist herbivore and by the specialist herbivore?

-The generalist herbivore may increase the abundance of the well-defended plant by choosing to eat other plant species. -The specialist herbivore may decrease the abundance of the well-defended plant by feeding exclusively on that species.

Identify examples of evidence that a population has a size that is density dependent.

-The number of progeny per adult decreases as population density increases. -A population's resources and potential mates are insufficient for all individuals.

In a population with delayed density dependence, if 𝑁1−𝜏 is greater than the carrying capacity, 𝐾, what is the predicted effect on population size? Assume that the intrinsic growth rate for the population, 𝑟, is positive.

-The population will become smaller.

Identify the statements that describe an evolutionary arms race between a predator and its prey.

-The prey evolves a wide array of defenses against its predators. -A predator evolves offenses to counter prey adaptations.

Scientists collected data on the wolf and moose populations on Isle Royale for several decades. Wolves are the only predator of the moose on Isle Royale, and moose are the wolves' main prey. Use the information in the graph to place the descriptions of the marked events in the sequence in which they occurred.

-The wolf population increased above its carrying capacity when food was plentiful. -The wolf population crashed after overshooting its carrying capacity. -The moose population responded to a drop in the number of wolves by increasing rapidly. - The moose population overshot its carrying capacity and crashed.

Under what circumstances is a delayed density dependent model appropriate for modeling populations?

-When there is a temporal disconnect between carrying capacity and population size.

A population of emperor penguins in Antarctica consists of 214 individuals and has an intrinsic annual growth rate of 0.07. Recent work by scientists shows that the waters where the penguins live are productive enough to sustain a maximum of 287 individuals. On a per capita basis, what is the penguin population's current annual rate of increase?

0.02 individuals

Scientists conducted a mark‐recapture survey on a population of crayfish. They captured 32 crayfish in a 300 m2 stretch of stream and marked these crayfish with fingernail polish. The crayfish were released and allowed to disperse in the stream for one day. The scientists captured a second sample of crayfish and found 24 marked crayfish out of a total of 48 crayfish in the sample. Calculate the density of crayfish in a 300 m2 stretch of stream if the estimated population size for this area is 64 crayfish.

0.21 crayfish m-2

You are studying a metapopulation of frogs living in a fragmented habitat consisting of numerous separate wetlands. In this metapopulation, the probability that any frog subpopulation will go extinct within one decade is 0.15. Further, the probability that any unoccupied patch could be colonized within the decade is 0.23. If the probability of extinction and colonization are in equilibrium, what is the probability that any patch in the metapopulation will be occupied within the next decade?

0.35

You are in charge of managing a population of wild quail species of conservation concern that live only in forest patches of a fragmented landscape in your area. You have estimated that the probability of any given forest patch being colonized by a quail subpopulation within the next 10 years is 0.22. Meanwhile, the probability of a quail subpopulation going extinct within any given forest patch within the next 10 years is 0.18. However, you are planning to build habitat corridors between forest patches to improve the connectivity of the quail subpopulations. You estimate that this will decrease the probability of a quail subpopulation going extinct within any given forest patch in the next decade to 0.07 and will increase the probability of colonization to 0.29. What proportion of more habitat patches do you expect the quail will occupy after you install the habitat corridors than before?

0.58

Researchers studied population distributions of shrubs in coastal California and tried to determine why there were bare spots around the shrubs. They hypothesized that the bare spots may have been associated with the density of mice found in those areas. They captured 12 mice in the bare zone around shrubs and 8 mice in the grassy areas adjacent to the bare zones. The scientists expected to find 10 mice in the bare zone and 10 in the grassy areas. Calculate the X2 ‑value for these data.

0.8

You recently examined the differences in population growth between several aquatic species. You tested a fish that reproduces once per year, an aquatic beetle that reproduces twice per year, and a species of zooplankton that reproduces approximately every 10 days. You place 50 individuals of each species alone in separate large outdoor tanks that hold thousands of gallons of water. Every year for 4 years, you determine the population size of each species and you record the following data: When you are interpreting your results, you realize that you forgot which species you put in which tank. Which answer most likely correctly matches the tank with the species that was in that tank during your experiment?

1 tank, z

You are studying the demographics of a lizard population on a Pacific island. The population when you begin studying it is 374 individuals. If the population has an intrinsic growth rate of 0.21, how big will the population be in 5 years?

1,068 individuals

Scientists spent 10 years measuring population parameters in gray squirrels in North Carolina. For each age class, x, they measures the number of individuals, nx, survivorship, lx, and fecundity, bx, of this population of squirrels. The data are shown in the table.The generation time, T, for these data is 2.68, and the net reproduction rate, R0, is 1.17.Calculate the intrinsic growth rate, λa, from these data.

1.06

Scientists spent 10 years measuring population parameters in gray squirrels in North Carolina. For each age class, x, they measures the number of individuals, nx, survivorship, lx, and fecundity, bx, of this population of squirrels. The data are shown in the table.Calculate the net reproductive rate, R0, from these data.

1.17

You are performing a static life table study of a spotted salamander population in western New York State. You have collected the following life table data on the number of female individuals alive at each of six age classes, the survival rate of females at each age class, and the fecundity of females belonging to each age class: Using this information, calculate the net reproductive rate of the females present when you collected these data.

1.56

Scientists collected data on two groups of organisms. The mean, 𝑥¯, equals 10 for the first group and 5 for the second group. In each group, the sample variance, 𝑠2, equals 4. The sample size, 𝑛, for the first group is 6 and for the second group is is 8. Determine the 𝑡critical ‑value for these data with the t‑table (link), assuming 𝛼 equals 0.05.

1.782

Using Figure 13.15 from the textbook (shown), which of the following populations would have the LOWEST probability of extinction?

10 individuals over 10 years

Researchers studied population distributions of shrubs in coastal California and tried to determine why there were bare spots around the shrubs. They hypothesized that the bare spots may have been associated with the density of mice found in those areas. They captured 12 mice in the bare zone around shrubs and 8 mice in the grassy areas adjacent to the bare zones.In order to perform a X2‑test, the expected values are calculated first. How many mice would the scientists expect to find within the bare zone and within the grassy areas?

10, 10

The R0 values for several human diseases are listed below. Which of the following would you expect to be most likely to cause an epidemic?

103

You are examining the metapopulation dynamics of a series of polar bear subpopulations on various ice-covered islands in northern Canada to determine the impact of melting ice on the future of the polar bear. You discover that from 2000 to 2010, polar bears occupied only 2 percent of available islands and that the probability of a polar bear subpopulation colonizing an unoccupied island from 2000 to 2010 was 28 percent. However, from 1990 to 2000, 10 percent of available islands were occupied by polar bears and the probability that an unoccupied island would be colonized by a polar bear subpopulation was 18 percent from 1990 to 2000. If we assume that the extinction and colonization rates were in equilibrium during each respective decade, approximately how much of an increase was there in the probability that a given polar bear subpopulation on an ice-covered island would go extinct?

11 percent

For the past two decades a scientist has been studying the population dynamics of a prairie dog town. Over the course of her study, the scientist calculated the population growth rate for different time intervals. She also determined that the carrying capacity for the town is 252 individuals. Using the logistic growth model, and assuming the intrinsic growth rate stayed the same throughout the study, at what population size would the scientist have found the fastest rate of growth?

135

You are an avid birdwatcher, and you have been documenting the population of ospreys, a large predatory fishing hawk, for 30 years. Ospreys breed only in the spring, and they overwinter in South America. When you began studying the ospreys in 1984, they were seriously threatened by human activities and the population that you were watching had only 21 individuals. You have happily watched as the ospreys slowly increased in abundance each year, and in your most recent survey in 2014, you found that their local population contained 142 individuals. In what year did the osprey population reach its doubling time from what it was when you first began studying it?

1999

Two groups of data have different means but the same standard deviations. What is the minimum number of standard deviations that would need to separate the two means in order for the means to be considered significantly different? Assume that 𝛼 is set at 5%.

2 standard deviations

Scientists spent 10 years measuring population parameters in gray squirrels in North Carolina. For each age class, x, they measures the number of individuals, nx, survivorship, lx, and fecundity, bx, of this population of squirrels. The data are shown in the table.Calculate the generation time, T, from these data.

2.67

If a life table projects a population size of 100 females and the sex ratio of the population is 1:1, how large is the entire population?

200

In a recent study, you monitored the age structure of a deer population for 4 years (2009-2012) by determining the age of deer that were killed by hunters. After determining the age of each individual, you calculated the percentage of deer from each of six age classes that were hunted in each year of your study. Your results are as follows: Given these data, in which time span is it most likely that deer food resources were unusually abundant in the region that supports this deer population?

2006-2007

Since its introduction in 2004, you have been tracking the population size of the invasive coquí frog in Hawaii, where the frog has no known predators. You have collected the following data: In what year did the coquí frog population likely overshoot its carrying capacity?

2011

A scientist in the Rocky Mountains is studying a population of pika, a small mammal that lives at high altitudes on mountainsides. The pika breeding season occurs once a year between May and June. Since pika prefer temperatures of less than 21°C (70°F), the warming temperatures resulting from global climate change have driven a subset of the population to form a new population at a higher altitude, in a region on the mountain previously uninhabited by pika. The scientist determined that in the first year, 2013, there were 9 individuals in the new population, and in the third year, 2016, there were 13 individuals. With this rate of population growth, by what year will the new pika population consist of 18 individuals?

2017

Suppose that from an initial size of 100 females, a life table based on female fecundity projects a population size of 112 females after one year. If the sex ratio of the hypothetical population is 1:1 , how large will the total population be after one year? State your answer as a whole number. total population size after one year:____individuals

224

You are performing a mark-recapture survey of sea turtles that breed on a beach on the east coast of Brazil once every year. In the initial sample, you capture 134 sea turtles and mark their shells. The next year, you return to the same beach and capture 157 sea turtles. Of those individuals, you find that 87 have markers from the previous year's survey. What do you estimate is the approximate size of the sea turtle population that reproduces on this beach?

242

You are performing a study to determine the growth rate of a population of trout fish in an aquaculture pond. You know that the intrinsic annual growth rate of trout, which breed year-round, is 0.13. The most recent count by the fish farmer concluded that the pond contained approximately 73,200 trout. Further, the farmer tells you that he supplies enough food for the pond to contain a maximum of 117,000 individuals. At the farmer's last check, what was the annual growth rate of the trout population in the pond?

3,562

Scientists collected data on two groups of organisms. The mean, 𝑥¯, equals 10 for the first group and 5 for the second group. In each group, the sample variance, 𝑠2, equals 4. The sample size, 𝑛, for the first group is 6 and for the second group is is 8. Calculate the t‑value for these two groups of organisms.

4.63

Following the introduction of the Myxoma virus into introduced European rabbit populations in Australia, what percentage of infected rabbits died during the third outbreak of the virus?

40-60 percent

You are examining the population dynamics of a butterfly metapopulation consisting of five highly suitable habitat patches of varying size and quality within a matrix of less suitable habitat. Within each patch, you record the number of individuals present when you began your study, as well as the average number of individuals that die and are born each year over the course of a decade. Finally, you estimate the maximum number of individuals that the patch can sustain given the resource availability and consumption rates of the individuals within each patch. With these data, you make the following table: If the birth and death rates of each patch remain fairly consistent for the future, which patch in this metapopulation is most likely to become the first source population?

5

A childhood friend and you are walking by a pond that you used to play in as kids. He claims to have counted the crayfish in the pond and bets you that there are 145. You take the bet and agree to do a mark-recapture survey to settle the bet. You grab some chest waders and a net and collect 79 crayfish in half an hour. You place a small dab of fingernail polish on each crayfish and put it back in the pond. You come back several weeks later, and using the same sampling techniques as before, you collect 115 crayfish. Approximately how many of these crayfish would have to be marked for your friend to win the bet?

63

You are hired by a farmer to solve her problem with groundhogs eating her crops. You look up groundhog life history and find that these animals mate and produce young only in the spring. You know that to address the farmer's problem with the groundhogs you must first understand how large the population is and how fast it is growing. You estimate that the current size of the groundhog population is 32 individuals and that the annual rate of growth is 1.73. What do you estimate the change in population size per year will be after 2 more years?

63 individuals

Scientists conducted a mark‐recapture survey on a population of crayfish. They captured 32 crayfish in a 300 m2 stretch of stream and marked these crayfish with fingernail polish. The crayfish were released and allowed to disperse in the stream for one day. The scientists captured a second sample of crayfish and found 24 marked crayfish out of a total of 48 crayfish in the sample. Estimate the population size of crayfish in the 300 m2 of stream.

64

Flixweed is a weedy plant introduced to North America. Studies of flixweed show that population size fluctuates cyclically and that the carrying capacity, 𝐾, equals 100, the intrinsic growth rate, 𝑟, equals 1.1, and the time delay, 𝜏, equals 1 year. If the population size in the first year is 20 and in the second year is 35, calculate the population size of flixweed in the third year.

66

Researchers in Texas are trying to determine the rate of decline of a particular bat population resulting from a recently introduced disease-causing pathogen. The researchers conduct a mark-recapture survey over a period of four years and record their data in a table.

70 bats per year

You are studying the metapopulation dynamics of a songbird species living in the forested patches of an otherwise predominantly agricultural landscape. In this landscape, there is a 64 percent likelihood that any given forest patch will be occupied by the songbird species within the next 5 years. However, there is also a 25 percent chance that any given songbird subpopulation will go extinct within the next 5 years. If the extinction and colonization rates in this metapopulation are in equilibrium, what is the approximate chance that any given forest fragment will be colonized within the next 5 years?

70 percent

You are studying the population growth of dragonflies in a wetland ecosystem, assuming ideal growth conditions. In this ecosystem, dragonflies breed only once per year over about 2 weeks. When you begin your study, you document that there are 250 dragonflies in the wetland. At the end of three reproductive cycles you calculate an annual growth rate of 0.67 in the population. What is the size of the population after three reproductive cycles?

75 individuals

An island can support a population of 1,340 birds with an intrinsic annual growth rate of 0.23. If this bird population is at its inflection point when the bird population size is plotted against time, what is the population's current growth rate per year?

77 individuals

Flixweed is a weedy plant introduced to North America. Studies of flixweed show that population size fluctuates cyclically and that the carrying capacity, 𝐾, equals 100, the intrinsic growth rate, 𝑟, equals 1.1, and the time delay, 𝜏, equals 1 year. If the population size is currently 102 plants and was 115 plants the previous year, estimate the population size of flixweed next year.

85

You are observing in two separate field habitats the distribution of five herbaceous plant species that require the same resources. You have previously documented that habitat patch A has approximately 140 percent higher levels of resources than habitat patch B. You take a census of individuals from all five species in both habitat patches and record your results in the following table: In which species is a barrier to dispersal, such as the presence of herbivores, most likely limiting the dispersal of individuals into an ideal free distribution?

A

Why do people sometimes introduce coevolved predators of invasive species as biological control agents in invaded ranges?

A coevolved predator species has evolved adaptations against the invasive prey species that predators in invaded territories do not possess.

Why might an herbivore that consumes many different species of plant be less successful at regulating the abundance of a well-defended plant species than an herbivore that specializes in eating a single species of plant?

A flexible herbivore will avoid the well-defended species in preference for easier food.

The metapopulation of California spotted owls is divided among several patches of suitable forest habitat. The forest patches differ in size, the number of owls they can support, the quality of the habitat, and their degree of isolation from other patches. Which combination of habitat characteristics would lead to the highest probability of extinction due to stochastic events for the owl population living on the patch?

A good-quality patch large enough for six owls that is reachable from two slightly larger, good-quality, somewhat distant patches.

Which of the following factors would determine the carrying capacity for a population?

A limited amount of habitat area for a territorial species.

Which of the following statements is/are true?

A parasite typically has one or a few host species, and a host is often infected by dozens of parasite species.

Suppose that 100 cattle are allowed to roam freely between two pastures, pasture A and pasture B. If the grass is three times more productive in pasture A than in pasture B, how many cattle would be in each pasture under an ideal free distribution?

A: 75 B: 25

What is the most likely method a scientist would use to determine whether a population of particular grass species has a nitrogen limitation?

Add nitrogen and measure whether the grass's population size increases.

What is true about the S-I-R model for infectious disease transmission?

All individuals begin as susceptible to the pathogen under study.

Which of the following statements regarding limiting resources is FALSE?

All resources have limiting effects on consumer populations.

Select the definition of net reproductive rate.

An estimate of the number of daughters a female produces in her lifetime.

According to the Lotka-Volterra model of predator-prey interactions, why do the populations of foxes and rodents cycle through periods of growth and decline?

As rodent numbers increase, predation rate by foxes also increases, which causes the rodent populations to decline.

Which of the following statements is/are correct regarding the S-I-R model?

As time progresses, the number of susceptible individuals should decrease and the number of recovered individuals increases.

When the diatoms Asterionella formosa and Cyclotella meneghiniana were raised together in a high silicate-to-phosphorus ratio, which of the following occurred?

Asterionella eventually reached much higher densities than Cyclotella.

Asterionella formosa and Synedra ulna are species of diatoms that rely on silicate (SiO2) . At carrying capacity, A. formosa drives the abundance of silicate down to 1 µM, whereas S. ulna drives the abundance of silicate down to 0.4 µM. Predict what will happen if Asterionella formosa and Synedra ulna attempt to inhabit the same space.

Asterionella formosa will not persist because there is insufficient silicate left in the environment by Synedra ulna.

Why are population growth rates at zero when two species are at equilibrium?

At equilibrium, both species have reached carrying capacity for the particular resource.

What is the most effective way to prevent the spread of mad cow disease?

Avoid feeding other cows the ground‑up bodies of infected cows.

You are performing an experiment to compare the ability of five fish species to distribute themselves in an ideal free distribution under laboratory conditions. Each species consumes the same food and eats the same amount per day. You test each species in separate but identical aquaria. Each day you add 1 mg of water fleas, a preferred fish prey item, to side A of the aquaria and 7 mg of water fleas to side B. Although you were unable to collect the same number of fish individuals from each species, you record the number of individuals of each species that distribute themselves on each side of their respective aquaria. You draw up the following table showing your results: Which fish species most closely exhibits an ideal free distribution under the laboratory conditions of your experiment?

B

In regions where the two species occur sympatrically, nonvenomous milk snakes have color patterns similar to the venomous coral snake, and studies indicate predators avoid both snakes in these regions. This is an example of _____.

Batesian mimicry

A researcher is studying the impact of climate change on the geographic ranges of the dominant plant species of the shortgrass prairie and the tallgrass prairie. The researcher selects one shortgrass prairie site in eastern Colorado and one tallgrass prairie site in central Kansas. Blue grama (Bouteloua gracilis) is the dominant plant of the shortgrass prairie. Big bluestem (Andropogon gerardii) is the dominant plant of the tallgrass prairie. Both sites have similar soils and topography but differ in their climate. Mean annual precipitation (MAP) at the shortgrass prairie site is 325 mm and mean annual temperature (MAT) is 9°C. MAP at the shortgrass site is 840 mm and MAT is 13°C. By performing a multiyear garden transplant study in which blue grama individuals are planted in Kansas and big bluestem individuals are planted in Colorado, the researcher ascertains conditions under which each species thrives best. Blue grama does the best when MAP ranges from 300 to 550 mm and MAT ranges from 8°C to 11°C. Big bluestem does best when MAP ranges from 525 to 950 mm and MAT ranges from 10°C to 15°C. Assume that each species' fundamental niche will stay the same as it was when the study was performed, and suppose that 100 years from now the MAP and MAT change at both sites. The MAP becomes 535 mm at the Colorado site and 940 mm at the Kansas site, and the MAT becomes 10.5°C at the Colorado site and 14.5°C at the Kansas site. Based on the findings from the researcher's garden transplant study, how do you think the geographic ranges of the two species will likely be affected?

Blue grama will stay within its current geographic range, and big bluestem will expand its geographic range westward.

Which of the following statements is/are true regarding the interaction between sea urchins and algae in rocky shore communities?

Both algae biodiversity is higher when sea urchins are present, and the total algal biomass is lower when sea urchins are present.

In the Lotka‐Volterra population modeling formulas how does the term "rN" in the prey equation compare to the term "acNP" in the predator equation?

Both terms are an attempt to quantify births.

In a forest, there is a population of gray squirrels and a population of chipmunks. The population of gray squirrels is 150 and the population of chipmunks is 100. Based on your understanding of the Lotka‐Volterra competition model, if the carrying capacity of the forest for gray squirrels is 300, what will the population of gray squirrels be when carrying capacity is reached?

Cannot be determined without knowing the competition coefficients

In the Lotka‐Volterra Competition model what is true about carrying capacity for species-1?

Carrying capacity for species-1 is determined by the number of individuals of species-1 and the number of individuals of species-2 (the competitor).

Why do closely related species often experience more intense competition than distantly related species?

Closely related species are more likely to rely on the same limiting resource.

According to the metapopulation model, what must happen for a metapopulation to persist?

Colonization of unoccupied patches must equal the number of subpopulations that have gone extinct.

If you were trying to save an endangered species that lived in a metapopulation, how might you try to to increase the proportion of occupied patches?

Decrease patch isolation.

Populations of collared lizards fluctuate over time as they approach and overshoot the carrying capacities of their habitats. In a metapopulation of collared lizards, how does decreasing the distance between habitat patches affect the synchrony of fluctuations among lizard subpopulations?

Dispersal is more frequent between nearby patches, so subpopulations fluctuate synchronously.

You are studying an herbaceous perennial plant that lives in a grassland habitat. The population size of this herbaceous perennial remained stable at its carrying capacity for roughly six consecutive years while precipitation and soil nitrogen were abundant. In the seventh year, the grassland experienced a severe drought, whereby precipitation and soil nitrogen significantly limited the growth of this herbaceous perennial. What do you predict is most likely to occur to this herbaceous perennial population?

Due to reduced precipitation and soil nitrogen, this herbaceous perennial population will overshoot its carrying capacity and experience a die-off.

In the Lotka‐Volterra population modeling formulas, when dN/dt = 0 or dP/dt = 0, what has happened?

Either the prey's (N) or the predator's (P) population is not growing.

Classify each statement as describing an endoparasite or an ectoparasite.

Endoparasite: - protected from most competitors and predators - easily acquires host's nutrients for feeding - includes viruses and other intracellular parasites Ectoparasite: - inaccessible to its host's immune system - vulnerable to variable external environment - easily moves to and from its host

Which of the following statements is/are true?

Endoparasites must cope with the immune system of their host, and ectoparasites have a high degree of exposure to their natural enemies.

Suppose that a scientist captures 20 fiddler crabs in a small freshwater pond and marks them before releasing them back to the pond. The following week, the scientist returns and captures 30 fiddler crabs, six of which are marked. What is the estimated size of the fiddler crab population? State your answer as a whole number.

Estimated size of population: 100 fiddler crabs

Identify statements as describing exploitative competition, interference competition, or apparent competition.

Exploitative competition: - A gray squirrel population collects food much more quickly than an eastern chipmunk population. - Both peregrine and prairie falcons search for suitable nesting sites on high trees and cliffsides. Interference competition: - A hummingbird population patrols and defends wildflower patches from other bird populations. - Young male deer challenge the dominant male of the group for mating privileges. Apparent competition: - Green and blue aphids eat the same plant species. The green aphid population crashes after ladybugs increase feeding on them. - Ducks and bullfrogs eat snails with a parasite that does not affect ducks and is fatal to bullfrog

True or false? In a delayed density dependence population model where the product of rτ is greater than 1.57, the population will exhibit damped oscillations.

False

True or false? Just as consumers can reduce the abundance of both renewable and nonrenewable resources, all resources can potentially limit consumer populations.

False

True or false? West Nile virus is spread from parent to offspring through vertical transmission.

False

What is NOT true about garlic mustard?

Garlic mustard is a highly effective competitor in wetlands.

What is the relationship between abundance of a species and the geographic range of the species?

Geographic range increases as abundance increases.

What is the difference in approach between the geometric growth equation and the exponential growth equation?

Geometric growth models species that reproduce at discrete times.

Classify each statement as applying to horizontal or vertical transmission of a parasite.

Horizontal transmission: - Transmission occurs between organisms of different species - A vector, such as a mosquito, transmits the parasite Vertical transmission: - Transmission occurs from a parent to its offspring - Death of the host does not occur until the host has reproduced

A type III functional response in predators is a result of which factors? I. prey refuges II. search images III. prey switching

I, II, and III

On a recent trip to the Amazon rainforest, you discover a new insect species. You perform some basic life history studies and discover three characteristics of this species: (1) This insect produces a large number of small-bodied young, which have low survivorship. (2) Individuals that survive their first year have very high survivorship for the next 2 years. (3) After individuals reach age 3, their survivorship drops significantly each year until they are 5, after which no individuals survive. This new insect species has a type _____ early-life survivorship curve, a type _____ midlife survivorship curve, and a type _____ late-life survivorship curve.

III; I; I

How could scientists use ecological niche modeling to fight the spread of the introduced emerald ash borer in North America?

Identify places to monitor in North America that have habitat characteristics similar to the emerald ash borer's native range.

What rule is used to determine whether the difference between the observed values and the expected values in a X2-test is significant?

If the X2-value is greater than the X2-critical values, then the observed and expected values are significantly different

Under which circumstance will a disease not spread beyond a few individuals in a population?

If the rate of infection is lower than the rate of recovery, the reproductive ratio of the infection will be less than 1.

What does an X2‑test measure?

If there is a significant difference between observed and expected values in a data set.

Why is extinction less likely in models of stochastic extinction that include density dependence than in models that exclude density dependence?

In density dependent models, the growth rate at low populations is higher.

Why does the density of a population tend to be negatively correlated to the adult body size of the species?

In species that live at high population densities, individuals have limited space for existing and obtaining resources, which restricts growth of individuals to a small body size.

In a metapopulation, what is the relationship between the amount of dispersal among subpopulations and the synchrony of fluctuations among subpopulations?

Increased dispersal among subpopulations causes the subpopulations to fluctuate at the same rate.

When the two diatom species Synedra and Asterionella were both grown together, eventually Synedra population numbers reached carrying capacity while Asterionella was driven to extinction. Initially, however, both species coexisted. Why was coexistence of both species followed by extinction of one of the two species?

Initially, there was enough of the resource (silica) for both species, but eventually one species outcompeted the other for the limiting resource.

Why is allelopathy considered a form of interference competition?

It allows a species to prevent its competitors from competing effectively.

What can the age structure of a population tell us about population fluctuations over time?

It can show times of particular growth or decline in previous years.

Landscapers interested in sustainable agricultural practices often use plants such as fragrant sumac and creeping thyme to suppress growth of unwanted weeds. These plants release chemicals into the ground, making the soil uninhabitable for competitors. How is this an example of interference competition?

It involves the use of chemicals to prevent competitors from accesing resources.

What does the joint equilibrium point of a Lotka-Volterra model represent?

It is the point at which both the predator and prey populations are stable and unchanging.

What can be inferred from two data sets that have normal distributions with a lot of overlap?

It is unlikely the data sets are significantly different from each other.

Which of the following methods does malaria utilize to enter the body?

It relies on mosquitoes to pierce the body of its host.

How is Leibig's law of the minimum related to a population's growth?

It states that a population increases until the most limiting resource prevents further increase.

The American bullfrog is native to eastern North America, but it has been moved by humans and thrives in western North America. What does this suggest about the cause of the bullfrog's historical range limit?

It was caused by an environmental barrier.

Explain why researchers commonly find a relationship between adult body size and population density.

Larger animals require more land to support their metabolism.

Which of the following scenarios would alter the estimate of population size in a mark‐recapture survey?

Loss of the marks on the marked individuals.

Before the 1800s, Macquarie Island was unused by humans. Since humans began using the island, it has been subject to both accidental and intentional introductions of non‑native species. Arrange the events and consequences of species introductions to Macquarie Island in the correct order.

Macquarie Island is unused by humans and harbors only native animals through the 1700s. -Seal hunters introduce house cats, which prey in part upon endemic seabirds. -Seal hunters introduce European rabbits, which consume native vegetation. -The abundance of plant species palatable to rabbits significantly decreases. -To control rabbit populations, scientists introduce rabbit fleas that carry Myxoma virus. -Island vegetation recovers slightly and cats exhibit prey-switching. -Increased cat predation devastates bird populations and causes at least two extinctions. -Scientists and government officials eradicate cats from the island. -Without cats, the rabbit populations rebound and the island's vegetation decreases again. -A concerted effort eradicates all non-native mammals from the island. Native plant and animal populations begin to recover and increase in size.

How can researchers understand if a human activity, such as pollution, negatively affects the abundance of a native species in a short amount of time?

Measure the density of the native species and a range of intensity of pollution in many different places. If pollution negatively affects the native species, there will be a negative correlation between the density of the native species and pollution.

How can a researcher use density to estimate the abundance of a species?

Measure the population density of a given species in many different places, calculate the average, and extrapolate to the entire are of interest.

A mark‐recapture survey is used to estimate a population's size using the variables 𝑀, the number of marked individuals, 𝑅, the number of recaptured individuals, and 𝐶, the number of individuals collected in the second sample. 𝑁 designates the population size. Select the equation used to estimate population size from a mark‐recapture survey.

N = (M x C)/R

The classic experiment conducted by Russian biologist Georgyi Gause that examined the competition between Paramecium caudatum and Paramecium aurelia demonstrated which of the following principles?

No two organisms can coexist indefinitely when they are in competition for the same resources.

Would it be effective to control a parasite by vaccinating individuals in a reservoir species infected by the parasite?

No, because the immune systems of the infected individuals are already resistant to the parasite.

What is one reason that using a parasite in an attempt to control an invasive host species might be problematic?

Over time, the parasite may become less deadly to the invasive species.

Carl Huffaker conducted an experiment using oranges and two species of mites, a prey species that eats the oranges and a predator species that eats the prey species. This work demonstrates that predator and prey populations can persist in nature when

PREY DISPERSE MORE EASILY THAN PREDATORS.

How does coevolution affect the relationship between hosts and parasites?

Parasites become less deadly over time.

What is true about habitat patches for any given species?

Patches vary in size and quality.

In a population that occupies multiple habitat patches, why shouldn't all individuals try to move to and live only in the habitat patch that has the highest-quality resources?

Per capita resource availability would be very low.

What is the difference between population abundance and population density?

Population abundance is the total number of individuals in a population, and population density is the number of individuals within a certain area.

What is the difference between population distribution and population dispersion?

Population dispersion is the spacing of individuals with respect to one another within a population.

Ecologists use the landscape metapopulation model to plan habitat restoration for specific species. What unique information do ecologists need for the landscape model as compared to the other two types of metapopulation models?

Quality of matrix surrounding the habitats.

A population of red backed salamanders (Plethodon cinerus) is increasing. Using life table calculations, what can you conclude about the Net Reproductive Rate (Ro)?

Ro>1

_____ populations typically have the highest probability of extinction.

Small

The H1N1 virus that normally infects birds but can also infect humans is commonly referred to as either _____.

Spanish flu or swine flu

In the experiment in which researchers examined the relationship between orb-weaving spiders and brown anole lizards, which of the following statements is/are true?

Spider populations became more abundant on islands without lizards.

What is an important difference between cohort life tables and static life tables?

Static life tables allow the study of species with much longer lifetimes.

In a life table, what is the fundamental difference between survival rate (sx) and survivorship (lx)?

Survivorship is the total percentage that has survived up to that age

Select the definition of generation time:

The average time between the birth of an individual and the birth of its offspring.

Why does a bird species typically have its highest population densities near the center of its geographic range?

The biotic and abiotic conditions at the center of the birds' geographic range are most ideal and support more individuals compared to the periphery.

Which of the following conclusions can be drawn regarding the coexistence of two species based on the Lotka-Volterra competition equations?

The coexistence of two species is most likely when interspecific competition is weaker than intraspecific competition.

When two competing species are each at equilibrium, why are their population growth rates zero?

The combined population size of the two competing species is at the carrying capacity of the environment.

When using a t-test, what is an important assumption regarding the distribution of the data?

The data has a normal distribution.

What is true about the density of a species within its geographic range?

The density of a species reflects the abundance of resources present.

White-nose syndrome in bats in North America is know as an emerging infectious disease for what reason?

The disease was first identified in North America in the 1970s.

In the S-I-R model for infectious disease transmission, when Ro>1, what is likely to occur?

The disease will continue to spread through the population.

Scientists studied the effect of predation on the activity levels of American toad and leopard frog tadpoles. The tadpoles were raised in one of two treatments. One treatment had a cage that contained a tadpole predator. The predator could not escape the cage and eat the tadpoles, but the predator secreted chemicals the tadpoles associated with predation. The control had empty cages. The scientists measured the activity level of tadpoles in the control and treatment. The data are found in the tables. What prediction would you make about the presence of the predator on tadpole behavior?

The effect of the predators on tadpole behavior is more likely to be statistically significant in the frogs than in the toads.

Identify the first step in calculating the X2‑value.

The expected values are subtracted from the observed values.

Why is the realized niche of a species considered to be a subset of its fundamental niche?

The fundamental niche is the area of a species' livable range of abiotic conditions, but the realized niche is the area other organisms do not prevent the species from occupying.

In the logistic growth model, when a population approaches carrying capacity, what happens to the population growth rate?

The growth rate slows to zero.

How might a type II functional response prevent a predator from controlling a large prey population?

The handling time will decrease the number of prey the predator can catch.

In models of delayed density dependence, why do intrinsic growth rate and amount of time delay determine the magnitude of population cycling?

The higher a population's maximum growth rate and the longer a population takes to respond to its environment, the more the population will overshoot and undershoot the carrying capacity.

In the Lotka‐Volterra Competition model, what is true about the competition coefficient of species-2 relative to the number of species-1 when carrying capacity is reached for species-1?

The higher the competition coefficient of species-2, the lower the population size of species 1 is when carrying capacity is reached.

Why are parasites often more lethal outside of their native range?

The host population in the new region lacks defensive adaptations against foreign parasites.

The study examining the effects of fertilizer and light on the growth of balsam plants demonstrated which of the following principles?

The increase in one resource can have a greater effect on a population when there is a simultaneous increase in a second resource.

In the S-I-R model, if R0 > 1, which of the following will occur?

The infection will spread and an epidemic will occur.

Scientists collected data on two groups of organisms. The mean, 𝑥¯, equals 10 for the first group and 5 for the second group. In each group, the sample variance, 𝑠2, equals 4. The sample size, 𝑛, for the first group is 6 and for the second group is is 8. What conclusion can be drawn about these data given a t‑value of 4.63 and a 𝑡critical ‑value of 1.782 at an 𝛼 of 0.05?

The means are significantly different because the t‑value is larger than the 𝑡critical‑value.

What is NOT true about a metapopulation?

The metapopulation as a whole does not experience population growth or decline.

Why are American elm trees less likely to die of Dutch elm disease now than when the disease was first brought to North America from Asia?

The most susceptible trees died in the initial outbreak and the more resistant survivors have passed their genes for resistance to their offspring.

According to the S-I-R model of parasite and host dynamics, how does the number of infections change over time if new susceptible individuals are born into the population at regular intervals?

The number of infected individuals fluctuates in a cyclical pattern.

Researchers studied population distributions of shrubs in coastal California and tried to determine why there were bare spots around the shrubs. They hypothesized that the bare spots may have been associated with the density of mice found in those areas. They captured 12 mice in the bare zone around shrubs and 8 mice in the grassy areas adjacent to the bare zones. The X2-value for these data is 0.800. Using the X2 ‑table and an 𝛼 of 0.05, what conclusion can be drawn from these data?

The number of mice found in the bare zone is not significantly different from the expected value of 10 mice.

In the logistic growth model, when is the population growing the fastest?

The population is growing fastest at the inflection point in the S curve of the logistic growth model.

Which is true of a stable age distribution?

The population will maintain the same age distribution.

In the logistic growth equation, when N is equal to K, which of the following will be true?

The population's growth rate will be zero.

The study examining the competitive ability of tadpoles of various species in the presence and absence of newts best illustrates which of the following concepts?

The presence or absence of predators may affect the outcome of competition.

Select the definition of the statistical variable 𝛼 (alpha).

The probability of determining two groups of data are different from each other when they are actually the same

How does the rate of infection differ from the rate of contact?

The rate of contact is the probability of a susceptible individual coming into contact with an infected individual, and the rate of infection is the number of susceptible individuals that the primary case infects within a given amount of time.

The basic model of metapopulation dynamics describes subpopulation extinction and habitat colonization. How does the rescue effect influence metapopulation dynamics?

The rescue effect reduces the probability of extinction and does not influence the probability of colonization.

What outcome is predicted by the following Lotka-Volterra model depicting competition between two species for a single resource?

The two species will coexist.

Why are some populations inherently cyclical?

There is a delay between the time of breeding and the birth of offspring.

What defines the limit of a population experiencing true exponential growth?

There is no limit.

Why are competition coefficients included in the Lotka-Volterra competition equations?

They convert between the number of individuals in one species and the number of individuals in the other species.

What is NOT a reason a single age group may be more abundant than younger age groups in a population's age structure?

They inherited an adaptation that made them survive better than subsequent generations.

True or false? Endoparasites experience greater difficulty moving to and from hosts than ectoparasites do.

True

True or false? In a population experiencing delayed density dependence, the amount of cycling in the population size depends on the product of the intrinsic growth rate and the time delay.

True

True or false? Resources, such as sunlight and precipitation, that originate from outside the system do not respond to the rate of resource consumption.

True

True or false? Wheat rust, which can severely reduce food production by severely damaging wheat crops, is an example of a fungal parasite.

True

Which functional response curve shows the slowest increase in the rate of predator consumption when prey are at low densities?

Type III functional response

Place the steps of the Lyme disease cycle in the correct order, beginning in spring when ticks hatch from eggs.

Uninfected ticks hatch from eggs as larvae ->Larval ticks feed on bacteria-infected rodents ->Infected larvae molt into the next developmental stage ->Nymphs engorge themselves on new host, then molt ->Adult ticks feed on deer blood and find mates ->-> Female ticks lay eggs

In terms of metapopulation modeling, what is a dispersal barrier?

Unsuitable habitat surrounding suitable habitat.

What is the relationship between generation time and the rate of population growth?

With a short generation time, the rate at which a population can grow is high.

Exponential growth is graphically represented as

a J-shaped curve.

When examining a population's age structure, it is possible to estimate when the population experienced unusually high birth rates if _____.

a certain age group contains an unusually high number of individuals

What is NOT an event that would eventually cause a population above its carrying capacity to undergo a die-off?

a decrease in the number of reproductive females

A search image refers to

a learned mental image that assists the predator in locating and capturing a prey item.

An advantage that endoparasites have when compared to ectoparasites is that endoparasites have

a low exposure to the varying external environmental conditions.

Which of the following best describes a prion?

a misfolded brain-associated protein that becomes pathogenic

Densities of cicada predators increase greatly during years of high cicada numbers. This is an example of _____.

a numerical response

When spruce budworm populations explode in northern spruce forests, often the density of bay-breasted warblers increase in response, from densities of 25 breeding pairs per square km to upwards of 300 breeding pairs per square km. This phenomenon would be considered

a numerical response.

The ideal free distribution concept refers to

a population of a species that is distributed between high and low quality habitat such that all individuals obtain the same benefit.

A successful mark and recapture survey that accurately depicts the population size of the species under study depends on all of the following EXCEPT

a population that is seasonally migratory.

Population cycles occur when _____.

a population's size fluctuates between high and low abundance in regular intervals

A mesopredator is

a predator that consumes only carnivores.

Dead leaves that fall from trees in the autumn and will not be regenerated until the following spring are an example of

a renewable resource.

Connell's work with barnacles in the intertidal zone of Great Britain provided evidence that

abiotic factors have a role to play in determining the outcome of competition.

After surveying a stretch of fresh water stream using the kick-net technique, you find the following general categories: 16 caddisflies, 12 mayflies, 3 aquatic sowbugs, 45 scuds and 7 midges. These figures reflect the of each of the organism types.

abundance

Suppose that 100 cattle were allowed to graze in either one of two pastures. If the grass was three times as productive in pasture A as in pasture B, how many cows would you expect in pasture A according to the ideal free distribution?

75

Plant A has seeds that are carried by the wind and plant B has seeds that are distributed by gravity. How would lifetime dispersal distance and neighborhood size differ for plants A and B?

A would have a greater lifetime dispersal distance and larger neighborhood size.

In the comparison of seed sizes consumed by desert ants and rodents, which of the following statements is true?

Ants consumed smaller seeds than rodents.

What practice increased the spread of mad cow disease?

adding dead cows to cow feed

You began studying the population growth of an invasive aquatic weed on August 23, 2005, when the population contained 350 individuals. You monitored the population's abundance every year from 2005 through 2010, when the population had 1,550 individuals. On August 23, 2010, what was the approximate instantaneous rate of change of the invasive weed's population size?

dN/dt = 240 individuals per year

What is it called when the magnitude of the fluctuations of a population's size around its carrying capacity decreases over time?

damped oscillations

A species whose population fluctuates around the carrying capacity (K), eventually levelling off at K, is said to display

damped oscillations.

Suppose we have a population that displays density dependent fluctuations in population size. The population's size last year was 27 individuals, and its current population size is 20 individuals. The carrying capacity for the population is 20, the intrinsic growth rate is 1.3, and 𝜏 equals one year. Predict how population size will change in the next year.

decrease in size

What will happen, in terms of population size in the future, when the age structure diagrams for a population are shaped like inverted triangles (point facing down)?

decreasing population size

Mathematical models used for determining how we can reduce the risk of Lyme disease indicate that _____.

decreasing rodent populations could drastically reduce the abundance of infected ticks

Populations cycle around their carrying capacity because of a(n) _____ response of the population to environmental changes.

delayed

When the environmental factors influencing a population are different in the past than in the present, this is termed

delayed density dependence.

When random variation in birth and death rates is due to genetic differences among individuals, it is called _____.

demographic stochasticity

A population of individuals whose birth and death rates vary due to differences among individuals is displaying

demographic stochasticity.

Finish the following sentence. A t‑test

determines if two means are significantly different from each other.

What is NOT accounted for in a model that considers age structure?

differences in survival between different years

What allowed H1N1 to jump to a new species of host?

direct transmission between members of the new host species

Subpopulations within a metapopulation often increase in synchrony when

dispersion is frequent.

What is NOT one of the five important characteristics of population distributions?

distension

In general, individuals living in sink subpopulations _____.

do not produce enough offspring to replace themselves

The range of conditions predicted to be suitable for a species is called a(n) _____.

ecological envelope

The spread of introduced species can be predicted using

ecological niche modeling.

Which type of organism is more likely to be removed from one species by another species?

ectoparasite

Natural disasters and other disturbances are a major concern for the persistence of _____.

endemic species

A population of individuals whose birth and death rates vary due to changes in environmental conditions is displaying

environmental stochasticity.

Individuals in populations with type I survivorship curves typically _____.

exhibit a high degree of parental care for offspring.

When the product of a population's intrinsic growth rate and time delay (i.e., τ) is greater than 1.57, the population will _____.

exhibit a stable limit cycle

In a metapopulation, when colonization (c) and extinction (e) rates in habitat patches achieve an equilibrium, the following equation predicts the proportion of patches that will be occupied at any given time: e = 1 - (p/c) p = 1 + (e/c) p = (c/e) - 1 p = 1 - (e/c) p = 1 + (c/e)

fourth equation

Wheat crops, corn crops, the American chestnut tree, the American elm, among others, have all been impacted negatively by which type of parasite?

fungal

The introduction of which of the following parasites led to the death of most chestnut and elm trees in North America?

fungi

White-nose syndrome in bats is caused by which of the following?

fungi

Which type of parasite causes athlete's foot in humans?

fungus

Studies dealing with white-nose syndrome in bats in New York State, and elsewhere in the northeastern United States, seem to indicate that the disease is caused by a _____ that may be native to _____.

fungus; Europe

The abundance of a population generally increases as its _____.

geographic range increases

You are surveying a plant species in the forest and find that the species displays a clustered dispersion pattern. What might NOT be a possible reason for such a dispersion pattern?

growth inhibiting substance produced by individuals

According to the Lotka‐Volterra model of change in the prey and predator population sizes, what is NOT a determinant of predator growth?

growth rate of prey

Relatively narrow strips of suitable habitat that connect large patches of suitable habitat are called _____.

habitat corridors

Which of the following resources is considered nonrenewable?

habitat space

Which of the following organisms is NOT considered an ectoparasite?

helminth

The story of the prickly pear cactus in Australia provides evidence that

herbivores can control the populations of other species.

Plants tend to have survivorship curves that graphically show

high early-in-life mortality.

Several helminthic parasites utilize snails, fish, and blue herons as hosts in their life cycle. When one of these parasites moves from a fish to a blue heron, it is utilizing _____.

horizontal transmission

When the H5N1 virus (bird flu) strikes an area, often one of the immediate responses of public health officials is to kill domestic flocks of birds, in an attempt to halt the transmission of the virus by way of

horizontal transmission.

Outbreaks of measles typically occur in two-year intervals in non-immunized populations. The timing of these epidemics is primarily the result of _____.

host immunity

What introduced species on Macquarie Island were most responsible for severely degrading the local biological communities, including the vegetation, birds, and invertebrates that were native to the island?

house cats and rabbits

The lifetime dispersal distance is most useful for predicting _____.

how fast a population will increase its geographic range

The lifetime dispersal distance of a species is useful in determining

how quickly a species might expand its geographic range.

You are going over the results of an experiment examining the impact of habitat corridors on the dispersal ability of bullfrogs. In your study, you placed 100 bullfrogs in a central pond and examined how many of the frogs wound up in each of five peripheral ponds. The peripheral ponds are equal to each other except for the type of habitat corridor connecting them with the central pond. You recorded the following data: If you were to build a new pond and connect it to the central pond, what type of habitat corridor would you use to maximize bullfrog dispersal?

humid forest

In the classic experiments of C. F. Huffaker using mites and oranges, what mechanisms allowed the predator and prey populations to persist?

increased dispersal of prey

According to the Lotka‐Volterra model of predator‐prey interactions, what follows a period of low prey population and low predator population?

increased predators and increased prey

Plants of a given population growing at lower densities have the advantage of decreased competition among individuals. What is NOT a potential disadvantage of plants of a given population growing at lower densities?

increased seed production

The probability that a habitat patch will be occupied at any given time _____.

increases as isolation from other patches decreases

The probability that a population will go extinct _____ with _____ population size and _____ time.

increases; decreasing; increasing

In mark-recapture surveys, a species' total population size is estimated by multiplying the number of _____ by the number of _____ and dividing by the number of _____.

individuals captured and marked in the first survey; individuals captured in the second survey; marked individuals recaptured in the second survey

Using the S-I-R model, identify each statement as describing the outcome over time of susceptible individuals, infected individuals, or recovered individuals. These individuals host the pathogen and and transmit the infection. These individuals acquire immunity through resistance and remain immune to any future infections. These individuals can be infected depending on rate of transmission and probability of infection on contact.

infected individuals recovered individuals susceptible individuals

A potential host that has the ability to prevent a parasite infection from occurring is said to possess which of the following?

infection resistance

A host that has the ability to minimize the damage that a parasite infection can cause is said to possess which of the following?

infection tolerance

The ability of the host to minimize the harm when a parasitic infection has occurred is called

infection tolerance.

The point on an S-shaped population growth curve where a population is growing at its fastest rate is called the _____ point.

inflection

The Lotka‐Volterra population modeling formulas for change in predator and prey population size over time requires that one know the

initial population sizes of both the predator and prey.

The common crow (Corvus brachyrhynchos) and a turkey vulture (Cathartes aura) both vying for the same dead animal carcass on the road by chasing each other away would be an example of

interference competition.

A habitat corridor

is an area of favorable habitat that connects two patches of similar habitat type, facilitating dispersal.

A species more likely to be susceptible to disturbance would be one that

is endemic

Which organism is NOT an endoparasite?

lice

Which is an advantage of an ectoparasite?

limited exposure to the host's immune system

To get the best sense of how a forest changes in composition from a lower elevation continuously to a high elevation, one would likely employ a

line transect.

Researchers who tie a string between two fixed points and count the number of individuals of a plant species that the string crosses are performing a(n) _____ survey of the plant population.

line-transect

The Christmas bird count is conducted every December by volunteers who spend a day following a predetermined path that covers a 24-km circle and counting the number of different bird species they see or hear within the circle. The Christmas bird count is considered a(n) _____ survey.

line-transect

When the population of a species is small in comparison to the carrying capacity, the

logistic growth curve looks like the exponential growth model.

Data for lynx and snowshoe hare populations in Canada have shown that the two species have an approximately 10-year cycle in population size. The data collected from the mid 1800s to the mid 1900s was obtained by

looking at trapping records.

What is an example of demographic stochasticity?

low fertility

Scientists that used fossilized tibiae bones of the dinosaur species referred to as the "good mother lizard" revealed this dinosaur had a type I survivorship curve where individuals in the youngest age class had _____ survival rates, individuals in the middle age class had _____ death rates, and individuals in the oldest age class had _____ survival rates.

low; low; low

A population will approach its carrying capacity without oscillations when the intrinsic growth rate is _____ and time delay is _____.

low; short

In the Lotka-Volterra model for predator populations, which of the following terms represents the death rate in the predator population?

mP

Bovine spongiform encephalopathy, also known as _____, is caused by _____.

mad cow disease; prions

According to the work of Gause, the carrying capacity is a figure that

may be altered, depending on resource availability.

Which variables are used to calculate the t‑value?

mean, variance, sample size

In the experiment examining the distribution of Poli's stellate barnacles and rock barnacles along Scotland's coast, which of the following would be expected to occur in the absence of periodic desiccation?

near complete coverage of available surfaces by rock barnacles

The self-thinning curve is evidence for

negative density dependence.

In the Lotka‐Volterra population model, the Joint Equilibrium Point is the point where

neither prey nor predator populations oscillate.

Which of the following ectoparasites are commonly associated with plants?

nematodes

According to the basic S-I-R model, the

number of infected individuals decreases over time.

Apparent competition

occurs when two species have a negative effect on each other through an enemy.

Which type of unoccupied patch would be more likely colonized?

one that is closer to an occupied patch

With the following Lotka-Volterra competition models, what is used to indicate the outcome of competition between two species for a single resource?

open circles

The Lotka-Volterra model takes which of the following variables into account?

oscillations in abundance of predators and prey

What was NOT involved in the decline of the black-footed ferret's population in the American West?

overharvesting for fur

When a population's size exceeds its carrying capacity, it is called a(n) _____.

overshoot

The Lotka‐Volterra (L‐V) population models used for predator and prey population size may be used for modeling parasite and host population sizes, provided that there is an understanding that

parasites may not remove their host from the population like predators do to their prey.

Generally, a population approaching its carrying capacity is likely to act like a _____.

pendulum approaching its vertical center

An ideal free distribution occurs when all individuals in a population have _____ and distribute themselves _____.

perfect knowledge of habitat variation; to achieve equal per capita benefits

Positive density dependence most commonly occurs when _____.

population densities are very low.

Leibig's law of the minimum states that _____.

populations are eventually limited by the scarcity of a resource

Which of the following factors least likely contributed to the rapid decline of black-footed ferret populations in North America in the early 1900s?

predation from natural predators such as coyotes

A parasitoid is a type of

predator.

The lower-than-expected prey consumption at low prey densities in a type III functional response can be explained by _____.

prey switching, an abundance of hiding places for prey, and inefficiency of predators searching for a scarce prey item

Garlic mustard dominates as a competitor against native plant species in many eastern and midwestern forests because it possesses the novel weapon of _____.

producing a chemical called sinigrin

Malaria is caused by which of the following parasites?

protozoan

A species' _____ is the range of abiotic and biotic conditions under which it lives.

realized niche

For maximum effectiveness, habitat corridors designed to allow the movement of species from one habitat area to another across an otherwise inhospitable environment should _____.

resemble the habitats that the corridor is connecting

The intrinsic growth rate for a species occurs when

resources are abundant and disease rate is at a minimum.

In models of delayed density dependence, what determines the magnitude of population oscillations?

rτ

A scientist is examining the effects of Japanese beetle herbivory on concentrations of defense chemicals in geranium plants. She randomly assigns individual geranium plants to two treatments, either high-intensity herbivory or low-intensity herbivory. Her results indicate that the mean concentration of defense chemicals in geraniums is higher when the plants are exposed to high-intensity herbivory and lower when exposed to low-intensity herbivory. After performing a statistical analysis on the data, she finds the means of the distributions overlap 3 percent of the time. Therefore, she concludes that defense chemicals in geranium plants are _____ different between high-intensity and low-intensity herbivory treatments.

significantly

What might prevent an ideal free distribution of cattle?

some cattle keep others out of the most productive pasture

Which of the following is an example of a resource in an ecosystem?

space

Which resource is a nonrenewable resource?

space

A pattern of population growth in which the population maintains large oscillations over time is called

stable limit cycle.

The probability of extinction due to stochastic processes declines as population size increases because

stochastic events have a proportionally smaller effect.

Which of the following phenomena can cause delayed density dependence in populations?

storage of excess energy by individuals

The effects of fire suppression on forests in the United States once dominated by longleaf pines could best be described as _____.

suppression of fire both reduced the number of fire-resistant plants in the community and allowed superior competitors that cannot tolerate fire to persist

Which is NOT a density-dependent factor?

temperature

A density-independent factor in temperate biomes might be

temperature.

The population cycles observed in the Hudson's Bay Company data examined by ecologist Charles Elton were approximately _____ in length.

ten years

Given these normal distributions, what would you predict about these two sets of data?

that 𝛼 (alpha) is likely less than 0.05

In the exponential growth model, what factor is NOT considered to determine the future size of a population?

the amount of resources available to the population

When considering the metapopulation concept, what is meant by the matrix?

the area between habitat patches that is less suitable for the species

What does the Lotka-Volterra competition model mathematically describe?

the competition for a limiting resource between two species

In the experiments discussed in Chapter 16 examining the competition between Asterionella and Synedra diatoms, what factor below most influenced the outcome of competition between them?

the concentration of silica in the water

A "search image" is associated with which of the following?

the efficiency with which predators capture prey

The species' geographic range is

the geographic area where a species may be found

The Lotka‐Volterra competition equations have four possible outcomes. Three of four possibilities have definite outcomes, while one outcome is contingent on

the initial population sizes of the two populations.

The doubling time for a population experiencing exponential growth is

the length of time for the population to double.

A predator's numerical response depends on

the migration of predators.

The logistic growth equation that forms the basis for the Lotka‐Volterra Competition equations can be calculated using all variables EXCEPT

the mortality rate of the population in question.

After garlic mustard was introduced to the United States 150 years ago, it became highly invasive due to _____; however, its competitive advantage has declined over the years because it has evolved to be _____, and because native plants have _____.

the novel weapon it possesses; less toxic to soil fungi; coevolved to combat it

Parasite load refers to

the number of parasites of a given species that a host can harbor.

In the Lotka‐Volterra population model, the Equilibrium Isocline is

the population size of the prey or predator that causes the population of the predator or prey, respectively, to be stable (i.e. growth =0).

The variable "c" in both the Lotka‐Volterra prey and predator equations is an attempt to quantify

the predator's ability to capture prey.

The concept of the ecological envelope refers to

the prediction of where a species might live

The concept that two species cannot coexist indefinitely when they are both limited by the same resource is called

the principle of competitive exclusion.

What is habitat fragmentation?

the process of breaking up large habitats into a number of smaller habitats

A realized niche is

the range of abiotic and biotic conditions in which a species persists.

The difference between a species' fundamental and realized niche is

the realized niche is post competitive

Continued control of European rabbit populations in Australia is accomplished primarily by _____.

the release of new strains of the Myxoma virus

To determine whether an infection will spread through a population using the S-I-R Model, we need to know everything EXCEPT

the reproductive rate of the population.

Studies of predation in the boreal and tundra regions of Canada suggest that, if a predator has a population cycle of a certain length, the prey that it consumes likely has a population cycle length that is

the same length.

Four data sets have been graphed with bar graphs. In each data set, there are two groups of data, A and B. The lines on each bar indicate the standard deviation for each group of data. In which of the data sets are A and B most likely to be significantly different from each other?

the smallest w no overalp

According to the S-I-R model, what happens when new susceptible individuals are born on regular intervals?

the state of infected individuals is cynical and steady

A population is particularly prone to overshoot its carrying capacity when _____.

the time delay between environmental change and reproduction is large

In a life table, the variable called Generation time (T) refers to

the time it takes for a seed to germinate, grow, flower, and produce its own seeds.

The first virus to be discovered was which of the following?

the tobacco mosaic virus

The parasite that causes Lyme disease is carried by _____.

ticks

What is the function of mark‐recapture surveys?

to estimate population size

The study conducted by Joseph Connell examining barnacle distribution along the coast of Scotland best illustrates which of the following principles?

tolerance for exterme abiotic conditions may determine the outsome of competition

Horizontal transmission of a parasite could best be described as _____.

transmission of a parasite between individuals other than parents and offspring

Transmission of a parasite by a vector could best be described as _____.

transmission of a parasite between two animals by a third organism, such as a mosquito

Vertical transmission of a parasite could best be described as _____.

transmission of a parasite from parent to offspring

Spiders that capture flies in a web are able to catch more flies at a constantly increasing rate until they suddenly reach saturation. This is an example of which of the following types of functional responses?

type I

When the number of prey consumed by the predator increases in a linear fashion as prey density increases until the predator is satiated, this is called a

type I functional response.

A survivorship curve that is characterized by high later-in-life mortality and high survivorship earlier in life is a

type I or mammal-like curve.

Crabs consuming mussels can consume more mussels at higher densities although the rate of increase is less than expected as a result of the handling time associated with each prey item consumed. This is an example of which of the following types of functional responses?

type II

In which of the following functional responses is the number of prey consumed per predator distinctly fewer than expected at low prey densities?

type III

What are competition coefficients?

variables that mathematically describe the conversion of the number of individuals from one species to the number of individuals of the other species

When the bacterium chlamydia is transferred from a mother to her baby during the birthing process, this is an example of _____.

vertical transmission

Which of the following are intracellular parasites?

viruses

If you were trying to estimate the abundance of zooplankton (small, free-swimming aquatic invertebrates) in a pond, what would be the best approach?

volume-based survey

The lifetime dispersal distance is the average distance that an individual moves from where it _____ to where it _____.

was born; reproduces

The competition coefficient value for a species would be higher if that species

were a better competitor for the resource in question.

Which is an example of coevolution?

when a predator and prey species both evolve crypsis

Canadian researchers working with forest tent caterpillars have shown that

when caterpillar populations are high, endovirus populations are high as well.

Under what conditions can two species competing for two resources coexist?

when each species can persist at a lower level of one of the two different resources

In the Lotka-Volterra competition model, under which circumstance can two species coexist?

when intraspecific competition is greater than interspecific competition

The concept of a species' ecological envelope is similar to its realized niche, except that an ecological envelope describes _____, whereas a realized niche describes _____.

where a species could live; where a species does live

Which scenario is an example of an invasive species?

zebra mussels released into the waters of the Great Lakes and spreading throughout much of the US leading to the decline of other native shellfish

Select the equation that models delayed density dependence in populations.

𝑑𝑁𝑑𝑡=𝑟⋅𝑁𝑡⋅(1−𝑁𝑡−𝜏𝐾)

Anthrax was one of the earliest discovered species of deadly _____.

bacteria

Galls are caused by which of the following organisms?

bacteria

Tuberculosis is a _____ parasite that usually affects the _____ of a human.

bacterial; lungs

Alarm calling, spatial avoidance, and reduced activity are all examples of which of the following?

behavioral defenses

Vertical transmission of parasites is a transmission

between a parent and its offspring.

Determining the age structure of populations is important because it can most reliably inform scientists about _____.

birth and death rates of individuals differing in age

When the West Nile virus is picked up by a mosquito feeding on one bird and transferred to another bird during the mosquito's next meal, this is an example of _____.

both a vector and a horizontal transmission

Which of the following behaviors have been observed in chimpanzees in response to parasite infection?

both chewing on bitter twigs from the Vernonia plant and swallowing Aspilia leaves whole

A forest herbaceous layer that has been invaded by garlic mustard is an example of

both interspecific and intraspecific competition.

You are studying the effects on the growth rate of each population of the density of monitor lizards that live on five small islands in the Pacific Ocean. On each island, you record the size of the island, the total number of lizards on the island, and the ratio of young lizards to adult lizards. You gather the following data: The population growth rate of this lizard species as it relates to density exhibits _____.

both positive and negative density dependence

Which of the following are intercellular parasites?

both protozoans and fungi

In a population of hosts, the rate at which a pathogen spreads throughout a population depends on _____.

both the rate of transmission and the rate of recovery

In the Lotka-Volterra model for prey populations, which of the following terms represents the loss of prey individuals due to predation?

cNP

The maximum population size of a species that can be supported by the habitat of that species is termed

carrying capacity.

Exploitative competition

causes the abundance of a resource to fall lower than other species can use.

Which technique do researchers use to count every individual in a population?

census

Which of the following diseases are caused by prions?

chronic wasting disease

A dispersion pattern that might indicate a heterogeneous pattern of resources would be called

clustered

You are studying the dispersion of six dandelion individuals in a small field population. In a table, you record the distance between each individual (rows) and every other individual in the population (columns): The six individuals in this small population appear to exhibit _____ dispersion.

clustered

David Tilman's study of two diatom species, each with differing abilities to utilize different levels of multiple resources, showed that

coexistence is possible if each species is more efficient at using a different resource than the other species.

A life table that is based on data collected by following a group of individuals in a population from birth to death is called a

cohort life table.

Interspecific competition is _____.

competition among individuals of different species

Intraspecific competition is _____.

competition among individuals of the same species

The protists that cause African sleeping sickness evade the host's immune system by _____.

continually changing the compounds on the surface of their bodies, making it difficult for the immune system to respond

The katydid is an insect well-known for utilizing which of the following modes of predator avoidance?

crypsis