Ecology Exam 3 Practice Problems
The transmission coefficient of hypothetical disease Dirks fever is 0.8. If the combined death and recovery rate is 0.4, what is the threshold for Dirks fever?
0.5
If there are 100 plants in a population in year 1, and 120 plants in the population in year 2, what is lambda?
1.2
A continuously growing population of bears has a population size of 500 and its intrinsic rate of increase is r= 0.07 per year. Assuming that this rate of increase remains the same, about how long should it take for the population to reach 1000?
10 years
In a mark-recapture study to estimate the size of a rodent population, researchers catch and mark 30 individuals. Two days later, they again capture a number of rodents and find that 20% of the individuals are marked. Assuming no births, deaths, or migrations, what is the estimated size of the population?
150
The population density of ground crickets at Oldmill Farm is about 15 per square meter. Assuming that the crickets are randomly distributed, about how many crickets would you expect to find in a rectangular section of land that is 6 meters x 2 meters?
180
According to the calculations done by Pearl and Reed in 1920, the carrying capacity of the United States is jut under ____ million.
200
A population has a current size of 150. If lambda is 1.2, what will the expected population size be after two generations?
216
If the population density of ocotillo in a desert is 15 per square kilometer, how many plants would be expected in an area that is 5 km x 3 km?
225
If there are 30 foxes in a population and 400 rabbits are present, the rate at which the prey will be killed is ____ per week.
24
The size of a population of beavers in a 5 x 5 km area is 675. What is the population density (in individuals per square km)?
27
A population of Drosophila mauritiana reproduces in synchrony at discrete time periods every generation, and generations occur at two week intervals. The current population size is 1,000, and its geometric population growth rate is 3.0 per generation. What will be the expected size of the population after 6 weeks?
27,000
A population of rabbits reproduces in synchrony at discrete time periods each year. If the current population is 150 and its geometric population growth rate is 1.4 per year, the expected size of the population after two years will be
294
Individuals of a plant species are counted in four transects that are each 2 x 3 meters. In these transects, 6, 15, 18, and 33 are found. What is the density per square meter of this species?
3
An entomology research team interested in controlling the spread of winter moths, an insect pest in the northeastern United States, samples a 150 square meter patch of woodland with four quadrats of 1 meter by 1 meter each. In quadrats A, B, C, and C, respectively, 10, 20, 35, and 15 individual winter moths are found. What is the best estimate for the total number of winter moths in that patch of woodland? ****
3000
A population of turtles contained 342 individuals at the end of the year 2010. Since then, 44 have died, 37 were born, 17 immigrated, and 6 emigrated. What is the population size now?
346
There are 80 swamp sparrows in a 20 hectare section of Mount Meadow. The average population density of the sparrows at this site is _____ per hectare.
4
In a mark-recapture study to estimate the size of a rodent population, researchers catch and mark 180 individuals. Two days later, they again capture a number of rodents and find that 40% of the individuals are marked. Assuming that there have been no births, deaths, or migrations, the estimated size of the population is ****
450
Individuals of a plant species are counted in five transects that are each 2 x 2 meters. In these transects, 8, 15, 19, 27, and 31 plants are found. What is the density per square meter of this species.
5
In a population of three asexual lizards, each lizard has a 40% probability of not producing any offspring. What is the probability that all three lizards will produce no offspring, ensuring the populations extinction?
6.4%
As of 2013, the human population size numbered just over
7 billion
A population of rodents contained 703 individuals at the end of March. During the month of April, 47 died, 17 were born, 57 immigrated, and 16 emigrated. What was the population size after those events?
714
A researcher studying apple maggot flies marks 180 flies in an orchid in Michigan. The next day, she collects 70 flies and finds that 14 are marked. If the assumptions of the mark-recapture method are met, what is the best estimate for the number of apple maggot flies in that orchid?
900
Suppose that a team of biologists wishes to estimate the population numbers of endangered lizards by means of line transects. Since distant lizards are difficult to see, the biologists will most likely use which method?
A detection function
Which statement about the study of the invasive Klamath weed and a leaf-feeding beetle is true? Plant populations cannot be reduced through herbivory. A leaf-feeding beetle reduced the density of an invasive weed. Both Klamath and the Chrysolina beetle are invasive.
A leaf-feeding beetle reduced the density of an invasive weed
A continuously growing population of alligators has a population size of 1000 and an intrinsic rate of increase of r=0.05 per year. Assuming that this rate of increase remains the same, about how long should it take for the population to grow larger than 4000 individuals?****
A little more than 27 years
Which population is likely to be increasing in size?
A population with a lambda of 1.3
Which population would be expected to remain stable in size? A population with an r of 1. A population with a lambda of 1. A population with an r of 0.
A population with a lambda of 1; a population with an r of 0
Assuming that their average population growth rates and all other factors are equal, which population would most likely be at risk for extinction?
A small population with high variation in its growth rate
Which species will most likely exhibit a regular or nearly regular pattern of dispersion?
A species that competes for a limiting resource that is equally distributed in space
A population of blowflies experiences logistic growth with delayed density dependence. Suppose that this population has an initial size of 4295 and follows the standard equation for delayed density dependence with a 10 week delay and an intrinsic growth rate of 0.2 per week. If these conditions remain constant and the population is tracked for a long time, what type of population dynamics should it display?
A stable limit cycle
Suppose that researchers are studying the life history of a population of gorillas, a species in which individuals can live for several decades. They can assess the ages of the gorillas with high accuracy, but because of funding constraints, they are limited to three years of study. Which table will the researchers be able to construct?
A static life table
Which of the following is most likely to prevent of stop an arms race between host and parasite?
A trade-off between a host's survival when parasitized and its reproductive success in the absence of parasitism
The predatory fish population will increase only if the number of minnows is
Above 100
All predatory relationships have the potential to reduce the ____ of the prey or host organisms. Survival Growth Reproduction
All of the above
Female in the wasp genus Nasonia typically lay eggs in the pupa of blowflies. The wasp eggs hatch into larvae, and the larvae kill and eat the fly pupa. Based on these observations, which statement is false? The wasps and the blowflies are engaged in a predatory relationship. The wasps are parasitoids, The wasps can be thought of as both predators and parasites, albeit unusual ones.
All of the above
How do tobacco plants respond to herbivory? They deter herbivores directly. They deter herbivores indirectly. They produce volatile compounds that attract predators and parasitoids of the herbivores.
All of the above
Life tables can be based on the: Ages of organisms. Life stages of organisms. Sizes of organisms.
All of the above
When animals are exposed to chronic stress, the stress response suppresses Growth Reproduction The immune response
All of the above
Which statement about population fluctuations is true? Population fluctuations can be caused in density-dependent factors. Population fluctuations can be caused in density-independent factors. All natural populations fluctuate in size.
All of the above
Which statement about the effects of the comb jelly on the Black Sea is true? At the peak of its outbreak in 1989, the biomass of this comb jelly was far grater than the world's entire annual commercial fish catch. This comb jelly is a voracious predator of young fish and fish eggs. By reducing the population sizes of zooplankton, this comb jelly indirectly caused phytoplankton population sizes to increase.
All of the above
Which statement about the hantavirus pulmonary syndrome (HPS) that emerged in the Four Corners region of the southwestern United States is true? The proportion of infected mice was correlated with the density of mice the previous year. The actual risk to people varied greatly with location due to factors including the microclimate and local food abundance. Rodents shed hantavirus in their saliva, urine, and feces.
All of the above
Which statement is consistent with projected trends in human population growth? According to the U.N., the low projection for human population size by the year 2050 is between 7 and 8 billion. According to the U.N., the high projection for human population size by the year 2050 is over 10 billion. The carrying capacity of humans depends greatly upon how we use resources.
All of the above
Which statement is not an assumption of the mark-recapture method of estimating population size? No individuals are born between the first and second captures. No individuals die between the first and second captures. Individuals do not move into or out of the study site between the first and second captures.
All of the above are assumptions of the mark-recapture method.
Which organisms cannot defend themselves against parasites? Birds Insects Plants
All of the above have ways of defending themselves against parasites
A fictional animal, the tribble, reproduces in synchrony at regular intervals. When the logarithm of a particular tribble population was plotted against time, the result was a straight and increasing line. Which statement about the tribble population is true? The tribble population is increasing in size geometrically. The lambda of the tribble population is constant and greater than 1. If the actual population size were plotted against time, the result would be an increasing J-shaped curve.
All of the above.
Which statement about populations is false? The distribution of a species is the geographic area where the abundance of the species is greater than zero. Populations are dynamic entities that vary in size over time and space. A population is a group of individuals from the same species that interact with one another within a particular area.
All of the choices are true.
Which statement about endoparasites is true?
All parasites living in the alimentary canal are endoparasites
Which statement is true? All pathogens are parasites. All parasites are pathogens. All symbionts are parasites.
All pathogens are parasites
Which event did not contribute to the recovery of the Black Sea during the 1990s?
Allee effects
The fungal parasite Cryphonectria parasitica is responsible for driving its host, the _____, to near extinction in North America
American chestnut
At low population densities, the flocking behavior of some species of birds is disrupted to the extent that the population growth rate is lower at very low densities than it is at somewhat higher densities. This is an example of:
An Allee effect
Due to their low density, females of a species of turtles have difficulty finding mates. As a result, the population's growth rate has been low, despite ample resources. This is an example of
An Allee effect
Which of the following could be considered the opposite of the density dependence seen in the standard logistic equation? Genetic drift. An Allee effect. Environmental stochasticity. Delayed density dependence.
An Allee effect
Which statement about density-dependent or density-independent growth is true? A decrease in birth rate with increasing population size is a density-independent factor. An increase in emigration rate with increasing population size is a density-dependent factor. Only density-independent factors can regulate population size. Density-independent factors do not have large effects on population size.
An increase in emigration rate with increasing population size is a density-dependent factor
Davidson and Andrewartha's studies of thrips showed that: Annual fluctuations in population size could be predicted based on rainfall and temperature data. Annual fluctuations in population size were due primarily to density-dependent factors. Density-independent factors increase the size of populations when population size is low.
Annual fluctuations in population size could be predicted based on rainfall and temperature data
Which of the following could not be a hemiparasite?
Any heterotroph
An evolutionary ecologist is studying evolutionary change in populations of lizards that reproduce via parthenogenesis. How do these individuals form?
Apomixis
Many species of butterflies are noxious to predators. They also have bright red coloration that indicates to the potential predators that they are unpleasant or even harmful to eat. This is an example of ____ coloration.
Aposematic
Suppose you are studying consumption patterns to determine how much land area would be required to support a certain population size, in terms of the number of tons of wheat produced by an area compared to the number of tons of wheat consumed by the people in that area. Based solely on wheat production and consumption, which area has the smallest ecological footprint?
Area 1: 600 tons of wheat produced, 200 tons consumed
Which statement about parasitic fungi, such as mildews, rusts, and smuts, is false?
At least some of these are hemiparasitic
Which statement best describes the relationship between snow geese and plants in the salt marshes that border the Hudson Bay?
At low densities, the geese benefit the plants; at high densities, the geese harm the plants
Zust and colleagues found that: Plants with aphids and without aphids grew the same. Average size of plants exposed to aphids increased over time. Rapid evolution may have occurred.
Average size of plants exposed to aphids increased over time and rapid evolution may have occurred.
Which statement about the Aleutian Island community is true? Without kelp, sea urchins in this community could not persist for long periods of time. Otters, which eat large quantities of food, like urchins as a source of food. By the end of the nineteenth century, otters had been hunted to near extinction, but their population abundances increased throughout much of the twentieth century.
B and C
In the simple host-pathogen model, which term describes the rate at which a disease is spread successfully?
BSI
Which type of mammals would you most likely find of a small oceanic island that is 2000 km away from any other land mass and has not been colonized by humans? ****
Bats
The minnow population size will increase only if the number of predatory fish is
Below 50
In the salt marshes bordering the Hudson Bay, the addition of snow geese to areas with no snow geese would likely ____ the marshes because geese ____. The addition of more geese to areas that already have large numbers of geese would likely ___ the marshes.
Benefit; add nutrients; harm
In the context of host-parasite dynamics, a latent period is the time
Between infection in a host and its own capacity to transmit the disease
Suppose you are studying two small lakes (lake 1 and lake 2) and how they change over time. A nearby farm accidentally spills fertilizer into lake 1. Around the same time, a non-native fish-eating turtle is introduced into lake 2. The ecosystems of both lakes are affected by these changes. What processes most likely explain how the lakes were affected?
Bottom-up control in lake1; top-down control in lake 2
In which ways can a parasite change an ecological community?
By changing the outcome of species interactions
In the Lotka-Volterra predator-prey model, the parameter a represents the
Capture efficiency of prey by predators
In some worm species, the actions of individual worms make the soil more hospitable to other members of the species. Such a phenomenon would tend to encourage which dispersion pattern?
Clumped
Which of the following best describes the most frequent dispersion pattern of the shrub Clematis fremontii in glades?
Clumped
Which population dispersion pattern is mostly commonly seen in the field for most species?
Clumped
In which organisms can one best observe the phenomenon of population cycles?
Collared lemmings in Greenland
Suppose that two species of rabbits inhabit an area. Which technique would provide estimates of their relative population densities, as opposed to estimates of their absolute densities?
Comparisons of the number of tracks made by each species
Insects feeding on the leaves of a plant stimulate the plant to produce new leaves. This is an example of
Compensation
GARP is most likely to be used in
Constructing niche models
Which of the following best explains why the mammal families in the Philippines are more similar to those in Africa than to those in New Guinea?
Continental drift
The hormone____ stimulates the release of stored glucose to make it available to muscles
Cortisol
Moths resting on the trunks of trees often resemble the tree bark so that potential predators do not perceive them as prey. This is an example of
Crypsis
Which organism has a survivorship curve most like that of humans living in the United States?
Dall mountain sheep
In the 1950s, Nicholson's experiments with blowflies showed that delayed density dependence can produce population cycles. If the experimental subject in these studies had been blowflies with somewhat lower growth rates, he most likely would have observed with pattern of population dynamics?
Dampened oscillations
Suppose a population of weevils that experiences logistic growth has an initial size of 1563 and follows the standard equation for delayed density dependence with a 5 week delay and an intrinsic growth rate of 0.15 per week. If these conditions remain constant and the population is tracked for a long time, what type of population dynamics should it display?
Dampened oscillations
Which of the following is a plausible consequence of delayed density dependence in a population that would otherwise have logistic growth? Increased environmental stochasticity Dampened oscillations Population cycles
Dampened oscillations, population cycles
Which statement about density-independent factors is true? Davidson and Andrewartha's studies of thrips showed that density-independent factors play a major role in the annual fluctuations of abundance of this species. Density-independent factors increase the size of populations when population size is low. Density-independent factors decrease the size of populations when population size is high.
Davidson and Andrewartha's studies of thrips showed that density-independent factors play a major role in the annual fluctuations of abundance of this species
The introduction of arctic foxes to some of the Aleutian Islands led to a drastic _____ in nitrogen-rich guano, and this change had the effect of transforming the islands from grassland to _____
Decrease; communities of small shrubs and forbs
Schoener and Spiller's studies, in which lizards were introduced into island in the Bahamas, showed that lizards ____ the densities of common spiders and _____ the densities of rare spiders.
Decreased; decreased
Which of the following is most likely to lead population cycles?
Delayed density dependence
Suppose that only two females and a small number of males are left in a population of a highly endangered bird. Although all of these birds are healthy, by chance, both females fail to reproduce and the population goes extinct. This extinction is best described as a consequence of:
Demographic stochasticity
Which of the following would be least likely to cause the extinction of a population comprising 20 individuals within a single generation? A natural catastrophe. Environmental stochasticity, Demographic stochasticity. Allee effects.
Demographic stochasticity
Population regulation occurs when
Density-dependent factors affect birth, death, and emigration rates
The logistic equation assumes that: Density-dependent factors are regulating population growth. The per capita growth rate increases with increasing density. The per capita growth rate is a constant. Density-dependent factors do not regulate population growth.
Density-dependent factors are regulating population growth.
Even without the presence of kelp, urchin barrens can persist for long periods of time because urchins have food sources other than kelp. These include freshly dead or partially decomposing remains of organisms, which are known as
Detritus
The most likely change caused by Vibrio cholerae in its host, which aides in dispersal to new hosts is
Diarrhea
Which of the following would be most influential in causing a clumped dispersion pattern among Seychelles warblers?
Differences in territory quality
Biologists looking at the population ecology of two Drosophila species, D falleni and D neotestacea individuals spend the day collecting these flies in a park. They obtain 160 D falleni and 74 D neotestacea individuals. Which statement is true? Based on these results, the biologists would be able to estimate absolute numbers of the two species. Differences in the activities of the two species, as opposed to differences in their respective population sizes, is a possible explanation for the differences in the number of each species collected. These results provide an example of niche modeling.
Differences in the activities of the two species, as opposed to differences in their respective population sizes, is a possible explanation for the differences in the number of each species collected.
Point sampling is a type of
Distance method
A detection function is most likely to be used in
Distance methods
A powerful ice storm in 1998 felled a large proportion of trees across much of northern New England, New York State, and southeast Canada. Although the storm led to declines in abundance for many species of birds, it created opportunities for other bird species. With regard to its effects on the abundance of bird species, the 1998 storm would be considered a
Disturbance event
According to the basic host-pathogen model, if the combined death and recovery rate from a disease doubles, and the effectiveness of the disease to spread from infected to uninfected individuals remains the same, the threshold density should
Double
Which of the following is an advantage that endoparasites have over ectoparasites?
Ease of feeding
The total area of productive ecosystems required to support a particular individual of population is known as its
Ecological footprint
Which statement about ecological footprints is false? The ecological footprint of the average American is much larger than that of the average person in the rest of the world. Ecological footprints of populations do not change over time Ecological footprints can be used to estimate carrying capacities. Calculations of ecological footprints are based on several sources of information, including agricultural productivity, resource use, and pollution.
Ecological footprints of populations do not change over time
A bacterium that causes a rash on the skin of mammals upon infection would be classified as a(n): Ectoparasite Endoparasite Microparasite
Ectoparasite and microparasite
Which statement about environmental stochasticity is true? Environmental stochasticity places grizzly bears in Yellowstone National Park at risk for extinction despite the average positive growth rate of this population. There is no fundamental difference between environmental stochasticity and demographic stochasticity. In a situation of environmental stochasticity, the underlying birth and death rates of individuals are constant across years.
Environmental stochasticity places grizzly bears in Yellowstone National Park at risk for extinction despite the average positive growth rate of this population.
The addition of excess nutrients into aquatic systems often disrupts the ecosystem. This phenomenon is known as
Eutrophication
In the years since Myxoma was introduced to Australia, the virus has ____ and rabbits have _____ resistance to the virus.
Evolved to become less lethal; evolved
During the 1950s and 1960s, the cattle egret was quickly colonizing Florida. What pattern of population growth best describes that of the cattle egret at that time?
Exponential growth
In a metapopulation setting, habitat fragmentation generally causes the ____ rate to increase and the _____ rate to decrease
Extinction; the colonization rate
If there are initially 30 foxes and 400 rabbits, the net growth rate in the fox population will be a ___ of ____ per week.
Gain; 1.8
If there are initially 30 foxes and 400 rabbits, the overall rate of change in the rabbit population will be a ____ of _____ per week.
Gain; 56
What is the technical term for the single genetic individual?
Genet
Although there are approximately 10,000 cheetahs left in the wild, biologists think that their numbers were much lower at some time in the past because cheetah populations have very little genetic variation. What is the most likely reason for the lack of genetic variability in cheetahs?
Genetic drift
Some Aleutian Islands are surrounded by urchin barrens while others are surrounded by kelp forests. Which statement gives the primary explanation for these differences? ****
Grazing by urchins prevents the formation of kelp forests.
The country of Guatemala is currently experiencing rapid population growth, Greece is experiencing essentially zero population growth, and Germany is experiencing negative population growth. Assuming that age-specific fecundities are similar in these three countries, which of the following is most likely?
Guatemala should have the highest proportion of young individuals
Lande's theoretical work contributed to the listing of the northern spotted owl as a threatened species in the United States. Which threat to the owl did Lande's work identify?
Habitat fragmentation
Which of the following can cause the population of a previously non dispersed species to develop a metapopulation structure? Genetic drift Demographic stochasticity Environmental stochasticity Habitat fragmentation
Habitat fragmentation
In Nicholson's experiments with blowflies, population cycles most often occurred when adults
Had an unlimited food supply and maggots had a limited food supply
Which of the following is not a difference between herbivores and carnivores?
Herbivores typically eat only a small part of the plant and carnivores eat the whole animal
The secondary compounds that are produced by oaks to reduce herbivory are an example of a(n)
Herbivory defense
Which statement about the hantavirus pulmonary syndrome (HPS) that emerged in the Four Corners region of the southwestern United States is false? The virus responsible for HPS had been in that area for at least 10 years prior to the outbreak. High levels of rainfall during the same year as the outbreak led to enhanced plant growth and thus mouse densities. The deer mouse, Peromyscus maniculatus, is a major carrier of the virus responsible for HPS. Researchers used satellite images to assess the level of plant food available just before the outbreak.
High levels of rainfall during the same year as the outbreak led to enhanced plant growth and thus high mouse densities.
Which principle is illustrated by Lande's theoretical work with spotted owls?
If the availability of suitable habitat for a species goes below a critical threshold, the entire metapopulation will collapse
Which of the following can help protect local populations fro extinction?
Immigration
Adult monarch butterflies over winter are found
In mountains west of Mexico City
In which way does the Lotka-Volterra predator-prey model of population growth differ from the logistic model/
In the Lotka-Volterra model, prey population growth does not depend on the availability of the predator's resources.
Which of the following should reduce the critical threshold for the spread of disease?
Increasing the rate at which individuals die
Which of the following is a violation of Levin's theoretical conception of a metapopulation that is often seen in a real metapopulation? Demographic stochasticity Genetic drift Isolation by distance Bottom-up control
Isolation by distance
Which negative effect can habitat fragmentation have on a metapopulation? It can make patches smaller, thus increasing the patch extinction rate. It can make patches more isolated, thus decreasing the patch colonization rate. It can lead to dampened oscillations within patches.
It can make patches smaller, thus increasing the patch extinction rate, and it can make patches more isolated, thus decreasing the patch colonization rate.
Which statement about cattle egrets in the Americas is false? Its arrival in South America was the result of a jump dispersal event. It continues to grow exponentially in Florida and other states in the southeastern United States. Its current distribution includes virtually all of the United States (except for Hawaii and Alaska). The patterns observed in the cattle egret are typical of species that disperse to new regions.
It continues to grow exponentially in Florida and other states in the southeastern United States.
Which statement about genetic drift is false? It can rapidly reduce the genetic variability of small populations. It is a process by which chance events influence which alleles are transmitted to the next generation. It is an allee effect. It can cause harmful alleles to occur at high frequency.
It is an allee effect
Which statement about Opuntia stricta is false? It is native to Australia. It was a pest species in Australia. Introducing a moth that feeds on Opuntia stricta led to the decline of both the abundance and distribution of this cactus. The distribution of this cactus in Australia was checked via biotic factors.
It is native to Australia
Which statement about parasite natural history is false? It is rare for a host species to have a parasite that feeds upon only that species. Different parts of human bodies provide suitable habitats for a wide range of parasites. Many species are host to more than one parasite species. Both large and small parasites typically feed on one or a few host individuals.
It is rare for a host species to have a parasite that feeds upon only that species
How does the protein transferrin assist in defenses against parasites?
It removes iron from the blood serum in vertebrate hosts and stores it in intracellular compartments
Which statement about a population that is growing, has reached a stable age distribution, and is maintaining this age distribution is false? Its lambda and growth rate will not be constant. The age structure of the population will not change from one year to the next. Each of the age classes will increase by a constant multiplier every year. The carrying capacity of the environment is constant.
It's lambda and growth rate will not be constant.
Which statement about the Black Sea is false? Its waters are well oxygenated from the surface to the floor of the sea. Because it is nearly land-locked, it exchanges little of its water with other ocean waters. Native predators and parasite failed to regulate its sea comb population. The state of its ecosystem improved between the early 1990s and the late 1990s.
Its waters are well oxygenated from the surface to the floor of the sea
Which statement about Duggins' urchin removal experiments is true?
Kelp did not become established in the control treatment.
In comparing exponential and geometric growth, which statement is true? Lambda can be calculated from r and is equivalent to the natural logarithm of r. Lambda can be calculated from r and is equivalent to e raised to the r power. The multiplier r can be calculated from lambda and is equivalent to e raised to the lambda. The multiplier r is not used in estimating exponential or geometric growth.
Lambda can be calculated from r and is equivalent to e raised to the r power.
Which statement expresses a conclusion of Jones and Diamond's studies of extinction in bird populations in the Channel Islands?
Larger populations are at less risk of going extinct than smaller ones are
Herbivores most commonly eat ____ of the plants.
Leaves
Larvae of agromyzid flies are typical of herbivorous insects. They feed off of ____ and tend to have _____ diets.
Leaves; narrow
Which pattern of population dynamics best describes that exhibited by sheep introduced to the island of Tasmania?
Logistic growth
A population that experiences delayed dependence will exhibit particular patterns of population dynamics depending upon rt(the population growth rate under ideal conditions x the time lag in the effects of density dependence). At low levels of this interaction, the population should exhibit _____; at intermediate levels, it should display _____; and at still higher levels, it should exhibit ______.
Logistic growth; dampened oscillations; stable limit cycles
Which of the following is the primary factor limiting the distribution of saguaro cacti in Arizona?
Low temperatures
A researcher who is interested in the number of individuals in a population of butterflies and their movement patterns would most likely use which method?
Mark-recapture
Huge numbers of adult periodic cicadas emerge simultaneously from pupae at intervals of either 13 or 17 years. This phenomenon is most similar to which of the following?
Masting
Which organism is an example of a hemiparasite?
Mistletoe
Over the past 2000 years, the overall human population has grown
More than exponentially
Suppose that a vertebrate has a mutation in the transferrin gene that makes the protein function less efficiently. Most likely, compared to individuals without the mutation, this individual would have ____ iron in its blood serum and ____ iron in the intracellular components of cells
More; less
Which statement about populations is false? If little is known about the distance that sexually reproducing organisms or their gametes move, the area that constitutes a single population is difficult to estimate. Population abundances change over time and space. A population may consist of a series of patches of individuals that are isolated in space but are connected by dispersal. Most organisms have similar capacities for dispersal.
Most organisms have similar capacities for dispersal
Which statement about the Black Sea is false? Because it is nearly land-locked, it exchanges little of its water with other oceans. Only the top layer (about a tenth of its average depth contains oxygen). Native predators regulate the sea comb population. The state of its ecosystem improved between the early 1990s and the late 1990s.
Native predators regulate the sea comb population.
Which statement about population growth is true? Exponential population growth is always faster than geometric population growth. We use the term "exponential growth" when the individuals in the population reproduce in synchrony at discrete individuals. A population that has a lambda of 0.88 should grow in size.
None of the above
Population cycles in all small rodents are driven by: Predators Parasites Competitors
None of the above; no universal cause of population cycles in small rodents has been identified
Only a small proportion of the world's species are found on each individual continent. Which organisms is exceptional and has a widespread distribution across most continents?
Norway rat
Which statement about enslaver parasites is false? The manipulation of cricket behavior by hairowqrms reduces the survival or parasitized crickets. Only invertebrates have been enslaved by parasites. Enslaver parasites manipulate their hosts in order to further their transmission to the next host. Several fungi species can alter the perching behavior of their fly hosts.
Only invertebrates have been enslaved by parasites
In Krebs and colleagues' study of snowshoe hare cycles, which of the following was a plausible reason for the failure of the +Food/-Predator treatment to stop hare population declines late in the cycle? Lynx can move great distances. Only some, but not all, predators were excluded in the treatment. Late in the cycle, the hares suffered maladies brought on by severe stress.
Only some, but not all, predators were excluded in the treatment and late in the cycle, the hares suffered maladies brought on by severe stress
According to the work of Estes and others, an increase in _____ would lead to an increase in the abundance of urchins.
Orcas
Thomas Park's studies of flour beetles and their protozoan parasite be exemplified the principle that
Parasites can alter the outcomes of competitive interactions within species
The studies by Dybdahl and Lively on snails and their parasites demonstrated that
Parasites infect common genotypes of snails more easily than they infect rare genotypes
Which statement about the snail-trematode system studied by Dybdahl and Lively is false? Parasites infected snails from their home lake less effectively than those from other lakes. The most common genotype of snail often varied from year to year. The parasites can castrate male snails. The parasite varied from year to year.
Parasites infected snails from their home lake less effectively than those from other lakes
Nasonia vitripennis is a wasp roughly the size of a drosophila fly. Adult females drill holes and lay eggs in the pupa of blowflies and related species. These eggs then hatch into larvae, which then eat the pupae. Thus, Nasonia vitripennis is a
Parasitoid
Which statement about parasitoids is false? Most parasitoids kill their hosts. Parasitoids lay eggs in or on another insect. Parasitoid larvae remain in the host insect but do not eat it.
Parasitoid larvae remain in the host insect but do not eat it.
What is the most likely reason that polar bears are found in the Arctic but not in Antarctica?
Polar bears, which were derived from brown bears that lived in the Northern Hemisphere, can migrate long distances, but they are either unable or unwilling to travel across tropical areas that lie between the Arctic and Antarctica.
Ecologists have been monitoring three metapopulations of butterflies. Population A has a patch colonization rate of 0.06 and a patch extinction rate of 0.12. Population B has a patch colonization rate of 0.04 and a patch extinction rate of 0.02. Population C has a patch colonization rate of 0.10 and a patch extinction rate of 0.14. According to Levin's metapopulation model, which population(s) would be expected to persist for a long time?
Population B only
Which pattern of population dynamics best described that exhibited by collard lemmings in Greenland?
Population cycles
Which statement about Nicholson's experiments with blowflies is true? Population cycles occurred when adults had limited food and maggots had unlimited food. Population cycles occurred when both maggots and adults had unlimited food. Population cycles occurred when both maggots and adults had limited food. Population cycles occurred when adults had unlimited food and maggots had limited food.
Population cycles occurred when adults had unlimited food and maggots had limited food.
Which principle is best illustrated by Erickson's studies of the shrub Clematis fremontii?
Population distributions can be patchy at several levels of spatial scale
Which of the following is an extreme case of population fluctuations?
Population outbreaks
Ecologists have been monitoring three metapopulations of sawflies. Population A has a patch colonization rate of 0.08 and a patch extinction rate of 0.11. Population B has a patch colonization rate of 0.05 and a patch extinction rate of 0.04. Population C has a patch colonization rate of 0.1 and a patch extinction rate of 0.08. According to Levin's metapopulation model, which of these populations would be expected to persist for a long time?
Populations B and C
Which of the following would not be an example of density-dependent factors regulating population size? The number of possible territories for robins is limited; thus when population sizes are high, a lower proportion of individuals can produce offspring. In conditions of overcrowding, some desert pupfish living in ponds will emigrate to other ponds if given the opportunity. Predation of mosquitofish is high, regardless of population size. In conditions of high density, mice are more susceptible to mortality from heat stress.
Predation on mosquitofish is high, regardless of population size
In Huffaker's studies of an herbivorous mite and its mite predator, when predator and prey were in a heterogeneous environment
Predators and prey persisted and exhibited population cycles
Different species of marine snails that are preyed on by a shore crab differ in terms of how easily the crab can crush their shells. Studies of these snails have provided evidence for the
Presence of trade-offs between different anti predator adaptations
In Huffaker's studies of an herbivorous mite and its mite predator, when predator and prey were in simple environment
Prey and predator populations both increased for a while, but soon crashed and went extinct
Area-based methods often make use of sampling areas of a defined size called
Quadrats
If the number of rabbits doubles and the number of foxes also doubles, the number of rabbits that are killed will
Quadruple
Suppose that the relative proportion of susceptible and infected individuals in a population remain the same, but the density of the overall population doubles. According to the BSI model, disease transmission should
Quadruple
Which of the following is not a biotic feature of the environment that can limit an organism's distribution or abundance?
Rainfall
Which term refers to a clone that is a physiologically independent plant?
Ramet
Some animals (e.g. whiptail lizards) and plants (e.g.strawberries) form clones of genetically identical, but physiologically independent (or potentially independent) and distinct individuals. These independent members of a clone are called
Ramets
Which statement about tuberculosis (TB) is false?
Recent advances in medicine and vaccines have cut the worldwide death rate from TB to less than 10,000 per year
Which of the following helped the Black Sea recover during the 1990s?
Reduction in eutrophication
In some trees and shrubs, competition among seedlings causes individuals to be evenly spaced throughout the habitat. These plants exhibit a _____ type of dispersion pattern.
Regular
In the Seychelles warbler, territorial behavior encourages a _____ population dispersion pattern, and cooperative breeding encourages a ____ population dispersion pattern.
Regular, clumped
In the simple host-pathogen model, which term describes the rate at which a susceptible individual encounters an infected individual
SI
Tapeworms have a _____, which they use to attach themselves to the insides of the host's intestine
Scolex
Which of the following provides a clear demonstration of logistic growth?
Sheep introduced to Tasmania
Kraaijeveld and colleagues performed studies with Drosophila strains that can mount an encapsulation defense. In the absence of encapsulation, wasp eggs that have the ability to avoid encapsulation hatch ____ other eggs that cannot avoid encapsulation. These studies demonstrate_____.
Slower than; the existence of trade-offs
Which observation led ecologists to conclude that resource limitation is not the only factor driving snowshoe hare cycles?
Some declining hare populations do not lack food.
In humans, red blood cells that have been infected with the parasite that causes malaria are destroyed mainly in the
Spleen
Mosquitos infected with Plasmodium carry cells of the ____ stage of the parasite. When an infected mosquito bites a human, these cells enter the ____, where they divide into ___ and then infect red blood cells.
Sporozoite; liver; merozoites
According to the basic host-pathogen model, if the combined death and recovery rate from a disease doubles, and the effectiveness of the disease to spread from infected to uninfected individuals also doubles, the threshold density should
Stay the same
Which statement about life tables is false? Life tables can be based on life-cycling stages as well as age. Survivorship (Ix) can increase from one age class to the next. The age-specific survival rate is the chance that an individual of one age will survive to the next age class. Fecundity is the average number of offspring produced by females of a particular age.
Survivorship (Ix) can increase from one age class to the next
Estes and his colleagues speculate that the decline in otters during the 1990s was due to a(n)
Switch in the predation patterns of killer whales (orcas) to include more otters
A bacterium that lives inside an aphid is always classified as a(n):
Symbiont
Which factor most likely affects the northern limit of the geographic range of monarch butterflies?
The availability of milkweed plants
Which of the following would likely result from a decrease in the density of the golden apple snail in an area that previously had large snail populations?
The biomass of aquatic plants would increase
Which statement about predators and prey is true? Mimicry is found only in prey, not in predators. The body form of the cheetah enables it to have great bursts of speed, improving its likelihood of capturing gazelles and other prey. Prey capture is facilitated in snakes by the rigid connections among their skull bones. Only herbivores have anti-predator defenses.
The body form of the cheetah enables it to have great bursts of speed, improving its likelihood of capturing gazelles and other prey.
Which statement about logistic growth is false? The carrying capacity is the maximum population size that can be supported by the environment for one year. At low densities, logistic growth is similar to exponential growth. At the carrying capacity, there is no population growth in the logistic model. Logistic growth of a population can be represented by an S-shaped curve.
The carrying capacity is the maximum population size that can be supported by the environment for one year
What factor is most responsible for the behavior pattern of young Seychelles warblers that postpone breeding and the establishment of their own nests in order to help their parents rear their siblings?
The clumped dispersion of populations
According only to the specific of Levin's metapopulation model, which variable is important in determining whether a metapopulation can persist for a long time? The spatial arrangement of patches. The colonization rate of patches. The extinction rate of patches.
The colonization rate of patches and the extinction rate of patches.
Which of the following is not an abiotic feature of the environment?
The density of earthworms present in the soil.
Which statement about malaria and the life cycle of Plasmodium is false? The chills and fever associated with malaria arise from the rupturing of red blood cells by large numbers of merozoites. The gamete-producing cells arise from sporozoites. The gametes of Plasmodium unite to form a zygote within the mosquito host. The typical zygotes produce thousands of sporozoites.
The gamete-producing cells arise from sporozoites
In the studies of clipping in gentians, plants that were clipped early in the season had _____ number of fruits, and plants that were clipped late in the season had _____ number of fruits.
The highest; the lowest
Which statement about Hairston and colleagues' studies of rotifer predators and their algal prey is false? The algal genotypes that were best at resisting predators were poor competitors. They most likely mechanism to explain the data was that rotifer egg viability increased with prey density. The studies were used both in mathematical modeling and experimentation. In treatments in which the prey could not evolve, typical Lotka-Volterra predator-prey cycles were observed.
The most likely mechanisms to explain the data was that the rotifer egg viability increased with prey density
Which statement about Arcese and Smith's studies of the effects of population density on song sparrows is false? The number of young per female that survived to become independent of their parents increased with increasing density. At high density, the population size of the sparrows was likely regulated by food shortages. The number of eggs laid per female declined with increasing density. Nesting pairs that were fed were found to produce many more young than did pairs in the control group.
The number of young per female that survived to become independent of their parents with increasing density.
The logistic equation assumes that: The per capita growth rate is a constant. The per capita growth rate declines with increasing density, Populations will increase in size indefinitely.
The per capita growth rate declines with increasing density
You see a high proportion of winged individuals in a population of the bean aphid. The most likely explanation is that
The population density is high or was high was the aphids developed
Large marine turtles called loggerhead sea turtles, which lay eggs in nests under sandy beaches, are currently listed as a threatened species. Which statement about these turtles is false? Egg and hatchling stages suffer high mortality rates. The hatchling stage is relatively easy to protect. The population would start growing it hatchling success were increased by at least 90%. Population growth rates will be most responsive to a decreased mortality of older juveniles and adults.
The population would start growing if hatchling success were increased by at least 90%.
What factor is most responsible for limiting the distribution of the perennial Clematis fremontii within the state of Missouri
The presence of glades
Which statement about Thomas and Jones's work on skipper butterflies is false? The probability of extinction was higher for populations in small patches than for those in large patches. The probability of colonization was higher for small patches than for large patches. Patches far from another occupied patch had a lower probability of colonization than patches near another occupied patch did.
The probability of colonization was higher for small patches than for large patches
Which statement does not represent an assumption of the Levin's model of metapopulation dynamics? Once a patch is colonized, its population quickly reaches carrying capacity such that population dynamics within patches can be ignored. A very large number of identical habitat patches exist. The spatial arrangement of patches determines the rate at which patches will receive colonists. All patches have the same probability of extinction.****
The spatial arrangement of patches determines the rate at which patches will receive colonists
Which statement about logistic growth is false? The standard logistic equation assumes that the carrying capacity is not constant. Changes in environmental conditions can cause the carrying capacity to fluctuate. The term logistic growth is used broadly to indicate any population whose numbers rise initially but then level off at maximum population size. Variation in the birth rate that occurs at a particular density can lead to variation in the carrying capacity.
The standard logistic equation assumes that the carrying capacity is not constant
Which parasite would most likely be found in the human small intestine?
The tapeworm Tania saginata
What was the difference between the treatment and the control groups in Arcese and Smith's studies of the effects of density on song sparrows?
The treatment group was provided with extra food
Based on the results of Dobson and Meagher's study of bison, which statement is false?
The use of a vaccine successfully raised the threshold density
Which statement about hantavirus pulmonary syndrome (HPS), which emerged in the Four Corners region of the southwestern United States is false? The virus responsible for HPS had only been in the area for about two years prior to the outbreak. High levels of rainfall during the previous growing season led to enhanced plant growth and thus to high mouse densities during the year of the outbreak. The deer mouse, Peromyscus maniculatus, is a major carrier of the virus responsible for HPS. Researchers used satellite images to asses the level of plant food available just before the outbreak.
The virus responsible for HPS had only been in the area for about two years prior to the outbreak.
Which statement about Pearl and Reed's application of the logistic growth curve to U.S. population growth is true? Their logistic curve provided a good fit to the U.S. population growth up until about 1950. They predicted a carrying capacity of over 300 million. The U.S. population exceeded the carrying capacity that they estimated by 1950.
Their logistic curve provided a good fit to the U.S. population growth up until about 1950
In a metapopulation, why does the colonization rate decrease as p becomes very large?
There are few empty patches available for colonization
What is the advantage for a male cricket parasitized by hair worms to seek out water?
There is no advantage to the cricket; the cricket's behavior is advantageous only to the parasite
How do snowshoe hares change when predators are abundant?
They alter their behavior
What do the fungus that causes athlete's foot, the tick that spreads Lyme disease, and body lice all have in common?
They are all ectoparasites
Which type of survivorship curve is seen most frequently in the wild?
Type III (most individuals die young)
Which strategy often improves the accuracy of estimates of population size based on area-based counts?
Using as many quadrats as possible
Which equation best describes the pattern of population dynamics of the sheep in Tasmania from their introduction to present day?
dN/dt=rN(1-N/K)
The rate of human population growth in 2016 was _____ than it was in the early 1960s and was about ______ % per year.
lower 1.1
A population of prickly pear cacti has 1500 individuals with an intrinsic rate of increase (r) of 0.3. As the population gets close to its carrying capacity of 2000 individuals, how will r change?
r will be near 0
Suppose populations of a beetle species follow the logistic equation for growth. If a population is at 3/4 of its carrying capacity, and its (per capita) growth rate in the absence of a density-dependent regulation is r, what is its growth rate now?
r/4
