BIO 109 UNIT II Picture Questions, Chapter 53, Unit 6 Mastering Biology, AP Biology Chapters 52-54 Test, biology exam 1

Select the correct statement describing the nitrogen cycle. Nitrogen-fixing microbes provide energy for carbon fixation. Denitrifying bacteria reduce ammonia (NH3 +) to molecular nitrogen (N2). Bacteria obtain energy from nitrification.

Bacteria obtain energy from nitrification.

Why is it that nitrogen is often a limiting plant nutrient, despite the fact that the atmosphere is 80% nitrogen gas (N2)? Because plants cannot assimilate nitrogen-containing compounds Because N2 easily leaches away from soil Because plants cannot fix N2

Because plants cannot fix N2

Select the correct statement(s) about the genetics of behavior. Select all that apply. Behaviors with a genetic component can evolve through natural selection. Learned behaviors are not subject to genetic influence. Most behavioral traits are determined by a single gene.

Behaviors with a genetic component can evolve through natural selection.

3) According to the logistic growth equation dN/dt = rmaxN(K — N)/K, A) the number of individuals added per unit time is greatest when N is close to zero. B) the per capita growth rate (r) increases as N approaches K. C) population growth is zero when N equals K. D) the population grows exponentially when K is small. E) the birth rate (b) approaches zero as N approaches K.

C

37) Which of the following might be expected in the logistic model of population growth? A) As N approaches K, b increases. B) As N approaches K, r increases. C) As N approaches K, d increases. D) Both A and B are true. E) Both B and C are true.

C

43) Density-dependent factors are related to which of the following? A) cohort B) dispersion C) Allee effect D) iteroparous E) semelparous

C

46) In which of the following habitats would you expect to find the largest number of K-selected individuals? A) a recently abandoned agricultural field in Ohio B) the sand dune communities of south Lake Michigan C) the flora and fauna of a coral reef in the Caribbean D) South Florida after a hurricane E) a newly emergent volcanic island

C

C

40) Which of the following graphs refer to this equation? dN/dt = 0.5 N

C

41) Which of the following graphs illustrates the population growth curve of single bacterium growing in a flask of ideal medium at optimum temperature over a 24-hour period?

E

42) Which of the following graphs illustrates the growth curve of a small population of rodents that has grown to reach a static carrying capacity?

A

43) Which of the following is a likely graphic outcome of a population of deer introduced to an island with an adequate herbivory and without natural predators, parasites, or disease?

D

44) Which of the following graphs illustrates the growth over several seasons of a population of snowshoe hares that were introduced to an appropriate habitat in northern Canada?

A population of glasswing butterflies exhibits logistic growth. The carrying capacity of the population is 200 butterflies, and Rmax, the maximum per capita growth rate, of the population is 0.10 butterflied/(butterflies per month). Calculate the maximum population growth rate for the population if the maximum growth occurs when N=K/2. Give your answer to the nearest tenth.

5.0 butterflies per month

Based on current growth rates, Earth's human population in 2012 will be closest to 10 billion. 2 million. 7 billion. 3 billion. 4 billion.

7 billion.

2) An ecologist recorded 12 white-tailed deer, Odocoileus virginianus, per square mile in one woodlot and 20 per square mile on another woodlot. What was the ecologist comparing? A) density B) dispersion C) carrying capacity D) quadrats E) range

A

22) Demography is the study of A) the vital statistics of populations and how they change over time. B) death and emigration rates of a population at any moment in time. C) the survival patterns of a population. D) life expectancy of individuals within a population. E) reproductive rates of a population during a given year.

A

29) A small population of white-footed mice has the same intrinsic rate of increase (r) as a large population. If everything else is equal, A) the large population will add more individuals per unit time. B) the small population will add more individuals per unit time. C) the two populations will add equal numbers of individuals per unit time. D) the J-shaped growth curves will look identical. E) the growth trajectories of the two populations will proceed in opposite directions.

A

31) In the logistic equation dN/dt = rN (K-N) K , r is a measure of the populationʹs intrinsic rate of increase. It is determined by which of the following? A) birth rate and death rates B) dispersion C) density D) carrying capacity E) life history

A

38) In models of sigmoidal (logistic) population growth, A) population growth rate slows dramatically as N approaches K. B) new individuals are added to the population most rapidly at the beginning of the populationʹs growth. C) only density-dependent factors affect the rate of population growth. D) only density-independent factors affect the rate of population growth. E) carrying capacity is never reached.

A

39) The Allee effect is used to describe a population that A) has become so small that it will have difficulty surviving and reproducing. B) has become so large it will have difficulty surviving and reproducing. C) approaches carrying capacity. D) exceeds carrying capacity. E) is in crash decline.

A

47) Which of the following characterizes relatively K-selected populations? A) offspring with good chances of survival B) many offspring per reproductive episode C) small offspring D) a high intrinsic rate of increase E) early parental reproduction

A

49) Your friend comes to you with a problem. It seems his shrimp boats arenʹt catching nearly as much shrimp as they used to. He canʹt understand why because originally he caught all the shrimp he could handle. Each year he added a new boat, and for a long time each boat caught tons of shrimp. As he added more boats, there came a time when each boat caught somewhat fewer shrimp, and now, each boat is catching a lot less shrimp. Which of the following topics might help your friend understand the source of his problem? A) density-dependent population regulation and intrinsic characteristics of population growth B) exponential growth curves and unlimited environmental resources C) density-independent population regulation and chance occurrence D) pollution effects of a natural environment and learned shrimp behavior E) a K-selected population switching to an r-selected population

A

6) The most common kind of dispersion in nature is A) clumped. B) random. C) uniform. D) indeterminate. E) dispersive.

A

68) An ecological footprint is a construct that is useful A) for a person living in a developed nation to consider to make better choices when using global food and energy resources. B) for a person living in a developing country to see how much of the worldʹs resources are left for him/her. C) in converting human foodsʹ meat biomass to plant biomass. D) in making predictions about the global carrying capacity of humans. E) in determining which nations produce the least amount of carbon dioxide from the burning of fossil fuels.

A

8) Which of the following groups would be most likely to exhibit uniform dispersion? A) red squirrels, who actively defend territories B) cattails, which grow primarily at edges of lakes and streams C) dwarf mistletoes, which parasitize particular species of forest tree D) moths in a city at night E) lake trout, which seek out deep water

A

9) A table listing such items as age, observed number of organisms alive each year, and life expectancy is known as a (an) A) life table. B) mortality table. C) survivorship table. D) rate table. E) insurance table.

A

48) Which of the following statements about the evolution of life histories is correct? A) Stable environments with limited resources favor r-selected populations. B) K-selected populations are most often found in environments where density-independent factors are important regulators of population size. C) Most populations have both r- and K-selected characteristics that vary under different environmental conditions. D) The reproductive efforts of r-selected populations are directed at producing just a few offspring with good competitive abilities. E) K-selected populations rarely approach carrying capacity.

C

30) Imagine that you are managing a large ranch. You know from historical accounts that wild sheep used to live there, but they have been extirpated. You decide to reintroduce them. After doing some research to determine what might be an appropriately sized founding population, you do so. You then watch the population increase for several generations, and graph the number of individuals (vertical axis) against the number of generations (horizontal axis). The graph will appear as A) a diagonal line, getting higher with each generation. B) an ʺS,ʺ increasing with each generation. C) an upside-down ʺU.ʺ D) a ʺJ,ʺ increasing with each generation. E) an ʺSʺ that ends with a vertical line.

D

32) In 2005, the United States had a population of approximately 295,000,000 people. If the birth rate was 13 births for every 1,000 people, approximately how many births occurred in the United States in 2005? A) 3,800 B) 38,000 C) 380,000 D) 3,800,000 E) 38,000,000

D

36) Often the growth cycle of one population has an effect on the cycle of another. As moose populations increase, wolf populations also increase. Thus, if we are considering the logistic equation for the wolf population, dN/dt = rN (K-N) K , which of the factors accounts for the effect on the moose population? A) r B) N C) rN D) K E) dt

D

4) A populationʹs carrying capacity A) can be accurately calculated using the logistic growth model. B) generally remains constant over time. C) increases as the per capita growth rate (r) decreases. D) may change as environmental conditions change. E) can never be exceeded.

D

4) During the spring, you are studying the mice that live in a field near your home. There are lots of mice in this field, but you realize that you rarely observe any reproductive females. This most likely indicates A) that there is selective predation on female mice. B) that female mice die before reproducing. C) that this habitat is a good place for mice to reproduce. D) that you are observing immigrant mice. E) that the breeding season is over

D

42) Which of the following describes having more than one reproductive episode during a lifetime? A) cohort B) dispersion C) Allee effect D) iteroparous E) semelparous

D

44) Which of the following is true? A) K-selection operates in populations where populations fluctuate well below the carrying capacity. B) r-selection occurs in populations whose densities are very near the carrying capacity. C) Different populations of the same species will be consistently r- or K-selected. D) r- and K-selection are two extremes of a range of life history strategies. E) r-selection tends to maximize population size, not the rate of increase in population size.

D

45) The life history traits favored by selection are most likely to vary with A) fluctuations in K. B) the shape of the J curve. C) the maximum size of a population. D) population density. E) population dispersion.

D

5) Which pair of terms most accurately describes life history traits for a stable population of wolves? A) Semelparous; r-selected B) Semelparous; K-selected C) Iteroparous; r-selected D) Iteroparous; K-selected E) Iteroparous; N-selected

D

7) Uniform spacing patterns in plants such as the creosote bush are most often associated with A) chance. B) patterns of high humidity. C) the random distribution of seeds. D) competitive interactions among individuals in the population. E) the concentration of nutrients within the populationʹs range.

D

8) Based on current growth rates, Earthʹs human population in 2010 will be closest to A) 2 million. B) 3 billion. C) 4 billion. D) 7 billion. E) 10 billion.

D

If you applied a fungicide to a cornfield, what would you expect to happen to the rate of decomposition and net ecosystem production (NEP)? Decomposition rate would decrease and NEP would increase. Decomposition rate would increase and NEP would decrease. Neither would change. Both decomposition rate and NEP would increase. Both decomposition rate and NEP would decrease.

Decomposition rate would decrease and NEP would increase.

Studying species transplants is a way that ecologists...

Determine if dispersal is a key factor in limiting distribution of organisms.

Which statement about dispersal is false? Dispersal occurs only on an evolutionary time scale. Colonization of devastated areas after floods or volcanic eruptions depends on dispersal. Seeds are important dispersal stages in the life cycles of most flowering plants. Dispersal is a common component of the life cycles of plants and animals. The ability to disperse can expand the geographic distribution of a species.

Dispersal occurs only on an evolutionary time scale.

In ecological terms, disturbance is an event such as a storm, fire, or human activity that changes a community, removing organisms and altering resource availability. Which of the following statements about the effects of disturbance is correct? A healthy community is in an equilibrium state of balance, with few disturbances. The effects of disturbance on a community are almost always negative. Disturbances can create patches of different habitats in a community.

Disturbances can create patches of different habitats in a community.

18) Which of the following examples would most accurately measure the density of the population being studied? A) counting the number of prairie dog burrows per hectare B) counting the number of times a 1 kilometer transect is intersected by tracks of red squirrels after a snowfall C) counting the number of coyote droppings per hectare D) multiplying the number of moss plants counted in 10, 1m2 quadrats by 100 to determine the density per kilometer2. E) counting the number of zebras from airplane census observations.

E

20) Which of the following assumptions have to be made regarding the capture -recapture estimate of population size? I. Marked and unmarked individuals have the same probability of being trapped. II. The marked individuals have thoroughly mixed with population after being marked. III. No individuals have entered or left the population by immigration or emigration, and no individuals have been added by birth or eliminated by death during the course of the estimate. A) I only B) II only C) I and II only D) II and III only E) I, II, and III

E

24) Natural selection involves energetic trade-offs between A) choosing how many offspring to produce over the course of a lifetime and how long to live. B) producing large numbers of gametes when employing internal fertilization versus fewer numbers of gametes when employing external fertilization. C) the emigration of individuals when they are no longer reproductively capable or committing suicide. D) increasing the number of individuals produced during each reproductive episode with a corresponding decrease in parental care. E) high survival rates of offspring and the cost of parental care.

E

41) Pacific salmon or annual plants illustrate which of the following? A) cohort B) dispersion C) Allee effect D) iteroparous E) semelparous

E

57) Field observation suggests that populations of a particular species of herbivorous mammal undergo cyclic fluctuations in density at three- to five-year intervals. Which of the following represent (a) plausible explanation(s) of these cycles? A) Periodic crowding affects the endocrine system, resulting in increased aggressiveness. B) Increases in population density lead to increased rates of predation. C) Increases in rates of herbivory lead to changes in the nutritive value of plants used as food. D) Increases in population density lead to more proximal infestations of parasites to host animals. E) All of the above are plausible explanations of population cycling.

E

62) Consider several human populations of equal size and net reproductive rate, but different in age structure. The population that is likely to grow the most during the next 30 years is the one with the greatest fraction of people in which age range? A) 50 to 60 years B) 40 to 50 years C) 30 to 40 years D) 20 to 30 years E) 10 to 20 years

E

(Refer to graph on the test) A population that is exhibiting this sort of growth is least likely to be regulated by...

Flood

A certain species of pine trees survives only in scattered locations at elevations above 2800 meters in the western United States. To understand why this tree grows only in these specific places, an ecologist should...

Investigate the various biotic and abiotic factors that are unique to high altitude.

Which of the following statements about human population in industrialized countries is incorrect? The survivorship curve is Type I. Average family size is relatively small. Age distribution is relatively uniform. The population has undergone the demographic transition. Life history is r-selected.

Life history is r-selected.

This graph shows the effect of removal of urchins and limpets (alone and together) on seaweed cover. Select the statement that accurately describes the results shown in this graph. Sea urchins have a much greater effect than limpets in limiting seaweed cover. Removing only limpets increased seaweed cover dramatically. The lack of change over time in the control plots (with urchins and limpets present) shows that limpets and urchins have no effect on seaweed cover.

Sea urchins have a much greater effect than limpets in limiting seaweed cover.

The correct answer: B and D

Secondary growth has occurred in the region(s) indicated by the letter(s) _____.

The principle of competitive exclusion states that two species cannot coexist in the same habitat. two species that have exactly the same niche cannot coexist in a community. competition between two species always causes extinction or emigration of one species. competition in a population promotes survival of the best-adapted individuals. two species will stop reproducing until one species leaves the habitat.

two species that have exactly the same niche cannot coexist in a community.

Which of the following is characteristic of most terrestrial biomes? clear boundaries between adjacent biomes a distribution predicted almost entirely by rock and soil patterns annual average rainfall in excess of 250 cm vegetation demonstrating vertical layering cold winter months

vegetation demonstrating vertical layering

(Refer to the diagram on the test) In this experiment, Balanus was removed from the habitat shown on the left. Which of the following statements is a valid conclusion of this experiment? a) Balanus can survive only in the lower intertidal zone because it is unable to resist desiccation. b) Balanus is inferior to Chthamalus in competing for space on rocks lower in the intertidal zone. c) The two species of barnacles do not compete with each other because they feed at different times of day. d) The removal of Balanus shows that the realized niche of Chthamalus is smaller than its fundamental niche.

d) The removal of Balanus shows that the realized niche of Chthamalus is smaller than its fundamental niche.

Population ecologists follow the fate of same-age cohorts to determine if a population is regulated by density-dependent processes. determine if a population's growth is cyclic. determine the factors that regulate the size of a population. determine the birth rate and death rate of each group in a population. determine a population's carrying capacity.

determine the birth rate and death rate of each group in a population.

During exponential growth, a population always quickly reaches its carrying capacity. cycles through time. grows at its maximum per capita rate. loses some individuals to emigration. grows by thousands of individuals.

grows at its maximum per capita rate.

When climbing a mountain, we can observe transitions in biological communities that are analogous to the changes in a community through different seasons. in biomes at different latitudes. in an ecosystem as it evolves over time. at different depths in the ocean. across the United States from east to west.

in biomes at different latitudes.

Which pair of terms most accurately describes life history traits for a stable population of wolves? semelparous; r-selected iteroparous; r-selected iteroparous; K-selected iteroparous; N-selected semelparous; K-selected

iteroparous; K-selected

Which of the following areas of study focuses on the exchange of energy, organisms, and materials between ecosystems? population ecology organismal ecology landscape ecology community ecology ecosystem ecology

landscape ecology

According to the equilibrium model of island biogeography, species richness would be greatest on an island that is environmentally homogeneous. small and remote. large and close to a mainland. small and close to a mainland. large and remote.

large and close to a mainland.

Which sensory distinction is not encoded by a difference in neuron identity? spicy and cool red and green salty and sweet white and red loud and faint

loud and faint

A population's carrying capacity increases as the per capita growth rate (r) decreases. generally remains constant over time. can be accurately calculated using the logistic growth model. may change as environmental conditions change. can never be exceeded.

may change as environmental conditions change.

Based on the intermediate disturbance hypothesis, a community's species diversity is increased by frequent massive disturbance. intensive disturbance by humans. stable conditions with no disturbance. human intervention to eliminate disturbance. moderate levels of disturbance.

moderate levels of disturbance.

Food chains are sometimes short because most producers are inedible. most of the energy in a trophic level is lost as it passes to the next higher level. predator species tend to be less diverse and less abundant than prey species. local extinction of a species causes extinction of the other species in its food chain. only a single species of herbivore feeds on each plant species.

most of the energy in a trophic level is lost as it passes to the next higher level.

Scientific study of the population cycles of the snowshoe hare and its predator, the lynx, has revealed that the hare population is r-selected and the lynx population is K-selected. the prey population is controlled by predators alone. both hare and lynx populations are regulated mainly by abiotic factors. hares and lynx are so mutually dependent that each species cannot survive without the other. multiple biotic and abiotic factors contribute to the cycling of the hare and lynx populations.

multiple biotic and abiotic factors contribute to the cycling of the hare and lynx populations

According to Hamilton's rule, natural selection is more likely to favor altruistic behavior that benefits an offspring than altruistic behavior that benefits a sibling. natural selection favors altruistic acts when the resulting benefit to the beneficiary, corrected for relatedness, exceeds the cost to the altruist. natural selection does not favor altruistic behavior that causes the death of the altruist. altruism is always reciprocal. the effects of kin selection are larger than the effects of direct natural selection on individuals.

natural selection favors altruistic acts when the resulting benefit to the beneficiary, corrected for relatedness, exceeds the cost to the altruist.

Which of the following sensory receptors is incorrectly paired with its category? rod-electromagnetic receptor taste receptor-chemoreceptor muscle spindle-mechanoreceptor olfactory receptor-electromagnetic receptor hair cell-mechanoreceptor

olfactory receptor-electromagnetic receptor

Female spotted sandpipers aggressively court males and, after mating, leave the clutch of young for the male to incubate. This sequence may be repeated several times with different males until no available males remain, forcing the female to incubate her last clutch. Which of the following terms best describes this behavior? promiscuity certainty of paternity monogamy polyandry polygyny

polyandry

According to the logistic growth equation the birth rate (b) approaches zero as N approaches K. the population grows exponentially when K is small. population growth is zero when N equals K. the number of individuals added per unit time is greatest when N is close to zero. the per capita growth rate (r) increases as N approaches K.

population growth is zero when N equals K.

Keystone predators can maintain species diversity in a community if they prey on the community's dominant species. allow immigration of other predators. reduce the number of disruptions in the community. prey only on the least abundant species in the community. competitively exclude other predators.

prey on the community's dominant species.

The oceans affect the biosphere in all of the following ways except producing a substantial amount of the biosphere's oxygen. moderating the climate of terrestrial biomes. removing carbon dioxide from the atmosphere. regulating the pH of freshwater biomes and terrestrial groundwater. being the source of most of Earth's rainfall.

regulating the pH of freshwater biomes and terrestrial groundwater.

The discipline that applies ecological principles to returning degraded ecosystems to a more natural state is known as conservation ecology. population viability analysis. restoration ecology. resource conservation. landscape ecology.

restoration ecology.

yes

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Although many chimpanzees live in environments containing oil palm nuts, members of only a few populations use stones to crack open the nuts. The likely explanation is that members of different populations have different nutritional requirements. the cultural tradition of using stones to crack nuts has arisen in only some populations. members of different populations differ in manual dexterity. the behavioral difference is caused by genetic differences between populations. members of different populations differ in learning ability.

the cultural tradition of using stones to crack nuts has arisen in only some populations.

A recent study of ecological footprints concluded that it is not possible for technological improvements to increase Earth's carrying capacity for humans. the ecological footprint of the United States is large because per capita resource use is high. Earth's carrying capacity would increase if per capita meat consumption increased. current demand by industrialized countries for resources is much smaller than the ecological footprint of those countries. Earth's carrying capacity for humans is about 10 billion.

the ecological footprint of the United States is large because per capita resource use is high.

The observation that members of a population are uniformly distributed suggests that the members of the population are competing for access to a resource. the size of the area occupied by the population is increasing. resources are distributed unevenly. the members of the population are neither attracted to nor repelled by one another. the density of the population is low.

the members of the population are competing for access to a resource.

Which of the following has the greatest effect on the rate of chemical cycling in an ecosystem? the production efficiency of the ecosystem's consumers the trophic efficiency of the ecosystem the location of the nutrient reservoirs in the ecosystem the rate of decomposition in the ecosystem the ecosystem's rate of primary production

the rate of decomposition in the ecosystem

The feeding relationships among the species in a community determine the community's species richness. secondary succession. trophic structure. species-area curve. ecological niche.

trophic structure

Which of the following biomes is correctly paired with the description of its climate? temperate broadleaf forest-relatively short growing season, mild winters tundra-long summers, mild winters temperate grasslands-relatively warm winters, most rainfall in summer savanna-low temperature, precipitation uniform during the year tropical forests-nearly constant day length and temperature

tropical forests-nearly constant day length and temperature

Suppose that the number of bird species is determined mainly by the number of vertical strata found in the environment. If so, in which of the following biomes would you find the greatest number of bird species? savanna tropical rain forest temperate grassland desert temperate broadleaf forest

tropical rain forest

The most plausible hypothesis to explain why species richness is higher in tropical than in temperate regions is that tropical communities are younger. tropical regions have very high rates of immigration and very low rates of extinction. diversity increases as evapotranspiration decreases. higher temperatures cause more rapid speciation. tropical regions generally have more available water and higher levels of solar radiation.

tropical regions generally have more available water and higher levels of solar radiation.

The transduction of sound waves into action potentials takes place within the middle ear as the vibrations are amplified by the malleus, incus, and stapes. as the basilar membrane vibrates at different frequencies in response to the varying volume of sounds. as the basilar membrane becomes more permeable to sodium ions and depolarizes, initiating an action potential in a sensory neuron. within the tectorial membrane as it is stimulated by the hair cells. when hair cells are bent against the tectorial membrane, causing them to depolarize and release neurotransmitter that stimulates sensory neurons.

when hair cells are bent against the tectorial membrane, causing them to depolarize and release neurotransmitter that stimulates sensory neurons

WHAT IF? If the direction of Earth's rotation reversed, the most predictable effect would be winds blowing from west to east along the equator. a loss of seasonal variation at high latitudes. no more night and day. a big change in the length of the year. the elimination of ocean currents.

winds blowing from west to east along the equator.

tesy

yrdy

Which of the following organisms is incorrectly paired with its trophic level? eagle-tertiary consumer fungus-detritivore cyanobacterium-primary producer zooplankton-primary producer grasshopper-primary consumer

zooplankton-primary producer

D

30) Which of the following is a conclusion that can be drawn from this graph? a. Female survivability is more negatively affected by larger brood size than is male survivability. b. Male survivability decreased by 50% between reduced and enlarged brood treatments. c. Both males and females had increases in daily hunting with the enlarged brood size. d. There appears to be a negative correlation between brood enlargements and parental survival. e. Chicks in reduced brood treatment received more food, weight gain, and reduced mortality.

59) Which of the following is a density-independent factor limiting human population growth? A) social pressure for birth control B) earthquakes C) plagues D) famines E) pollution

B

56) Which of the following can contribute to density-dependent regulation of populations? A) the removal of toxic waste by decomposers B) intraspecific competition for nutrients C) earthquakes D) floods E) weather catastrophes

B

A female zebra finch reared by a father with a red feather taped to his head will select a mate with a similar ornament over an unornamented male. What are plausible ultimate explanations for this behavior? Select all that apply. A female zebra finch that chooses a mate that resembles her father is more likely to choose a mate from her own species. A female zebra finch learns to recognize suitable mates by observing her father. Zebra finches are able to perceive ornamentation on other birds.

A female zebra finch that chooses a mate that resembles her father is more likely to choose a mate from her own species.

(Refer to the picture on the test) The range of cattle egrets has expanded between 1937 and today. How would an ecologist likely explain the expansion of the cattle egrets?

A habitat left unoccupied by native herons and egrets met the biotic and abiotic requirements of the cattle egret transplants and their descendants.

Which of the following may result from resource partitioning? Select all that apply. A population's fundamental niche may be smaller than its realized niche. A population may have a smaller realized niche when it coexists with a competitor. Competing species may partition time, feeding at different times of day.

A population may have a smaller realized niche when it coexists with a competitor. Competing species may partition time, feeding at different times of day.

Your textbook states, "Like organisms, ecosystems are open systems." Which of the following provide a legitimate example to illustrate this statement? Select all that apply. A population of reef fishes with a high reproductive rate in a mangrove ecosystem may be a source of recruits for a population in an adjacent coral reef ecosystem with a lower reproductive rate. Detritivores in soil consume nonliving organic matter and make the nutrients available to plants. Earth's atmosphere is bombarded by about 1022 joules of solar radiation each day.

A population of reef fishes with a high reproductive rate in a mangrove ecosystem may be a source of recruits for a population in an adjacent coral reef ecosystem with a lower reproductive rate. Earth's atmosphere is bombarded by about 1022 joules of solar radiation each day.

Consider a population whose growth over a given time period can be described by the exponential model: dN/dt = rN. Select the correct statement about this population. A population with an r of 0 will have no births or deaths during the time period under consideration. A population with a positive value of r will grow exponentially. A population with an r of 0.1 will decrease over time.

A population with a positive value of r will grow exponentially.

Some aquatic ecosystems have inverted biomass pyramids, in which primary consumers outweigh the producers. Why is it that a pyramid of biomass, but not a pyramid of net production, may be inverted? A pyramid of biomass may be inverted because it is based on biomass at one point in time. Pyramids of net production are based on productivity per unit time. A pyramid of biomass may be inverted when the producers (e.g., phytoplankton) are much more plentiful than the consumers (e.g., zooplankton). Producers are always outnumbered by consumers, so pyramids of net production are never inverted. A pyramid of biomass may be inverted when the producers (e.g., phytoplankton) are much smaller than the consumers (e.g., zooplankton). Producers always have higher productivity than consumers, so pyramids of net production are never inverted.

A pyramid of biomass may be inverted because it is based on biomass at one point in time. Pyramids of net production are based on productivity per unit time.

6) During exponential growth, a population always A) grows by thousands of individuals. B) grows at its maximum per capita rate. C) quickly reaches its carrying capacity. D) cycles through time. E) loses some individuals to emigration.

B

Select the correct statement(s) about a terrestrial food chain. Select all that apply. The total biomass of the top trophic level is greatest because the top consumers are large. About 1% of the energy stored in producers is converted to organic matter at the secondary consumer level. Energy is transferred from decomposers to plants to herbivores to carnivores.

About 1% of the energy stored in producers is converted to organic matter at the secondary consumer level.

(Refer to the table on the test) Using the table above, determine which age class year would hurt the population growth most if it were wiped out by disease.

Age class year 1

58) Which of the following is an incorrect statement about the regulation of populations? A) The logistic equation reflects the effect of density-dependent factors, which can ultimately stabilize populations around the carrying capacity. B) Density-independent factors have an increasingly greater effect as a populationʹs density increases. C) High densities in a population may cause physiological changes that inhibit reproduction. D) Because of the overlapping nature of population-regulating factors, it is often difficult to precisely determine their cause-and-effect relationships. E) The occurrence of population cycles in some populations may be the result of crowding or lag times in the response to density-dependent factors.

B

Examine the climograph for some major North American biomes. Which two factors influence the distribution of organisms, as shown in this climograph? The presence of tundra and presence of forested land Annual mean temperature and annual mean precipitation The presence of broadleaf and presence of coniferous forest

Annual mean temperature and annual mean precipitation

A

Assuming these age-structure diagrams describe human populations, in which population is unemployment likely to be a societal issue in the future? a. I b. II c. III d. No differences in the magnitude of future unemployment would be expected among these populations. e. It is not possible to infer anything about future social conditions from age-structure diagrams.

C

Assuming these age-structure diagrams describe human populations, which population is likely to experience zero population growth (ZPG)? a. I b. II c. III d. I and II e. II and III

Consider a population whose growth can be described by the logistic growth model: dN/dt = rmaxN[(K − N)/K]. Which of the following statements about this population is true? rmax declines as N increases. At low values of N, the logistic growth and exponential growth (dN/dt = rN) models predict similar population growth. K is a constant value.

At low values of N, the logistic growth and exponential growth (dN/dt = rN) models predict similar population growth.

(Refer to graph on the test) If a fish farmer wanted to harvest his fish so that it recovered at the maximum rate, where should population be maintained?

B

10) Life tables are most useful in determining which of the following? A) carrying capacity B) the fate of a cohort of newborn organisms throughout their lives C) immigration and emigration rates D) population dispersion patterns E) reproductive rates

B

27) Which of the following pairs of reproductive strategies is consistent with energetic trade-off and reproductive success? A) Pioneer species of plants produce many very small, highly airborne seeds, while large elephants that are very good parents produce many offspring. B) Female rabbits that suffer high predation rates may produce several litters per breeding season, and coconuts produce few fruits, but most survive when they encounter proper growing conditions. C) Species that have to broadcast to distant habitats tend to produce seeds with heavy protective seed coats, and animals that are caring parents produce fewer offspring with lower infant mortality. D) Free-living insects lay thousands of eggs and provide no parental care, while flowers take good care of their seeds until they are ready to germinate. E) Some mammals will not reproduce when environmental resources are low so they can survive until conditions get better, and plants that produce many small seeds are likely found in stable environments.

B

28) A population of ground squirrels has an annual per capita birth rate of 0.06 and an annual per capita death rate of 0.02. Estimate the number of individuals added to (or lost from) a population of 1,000 individuals in one year. A) 120 individuals added B) 40 individuals added C) 20 individuals added D) 400 individuals added E) 20 individuals lost

B

3) To measure the population density of monarch butterflies occupying a particular park, 100 butterflies are captured, marked with a small dot on a wing, and then released. The next day, another 100 butterflies are captured, including the recapture of 20 marked butterflies. One would estimate the population to be A) 200. B) 500. C) 1,000. D) 10,000. E) 900,000.

B

35) As N approaches K for a certain population, which of the following is predicted by the logistic equation? A) The growth rate will not change. B) The growth rate will approach zero. C) The population will show an Allee effect. D) The population will increase exponentially. E) The carrying capacity of the environment will increase.

B

40) Which of the following is the pattern of spacing for individuals within the boundaries of the population? A) cohort B) dispersion C) Allee effect D) iteroparous E) semelparous

B

5) You are observing a population of lizards when you notice that the number of adults has increased and is higher than previously observed. One explanation for such an observation would include A) reduction in death rate. B) increased immigration. C) increased emigration. D) decreased emigration. E) increased birth rate.

B

50) Carrying capacity is A) seldom reached by marine producers and consumers because of the vast resources of the ocean. B) the maximum population size that a particular environment can support. C) fixed for most species over most of their range most of the time. D) determined by density and dispersion data. E) the term used to describe the stress a population undergoes due to limited resources.

B

(Refer to the diagram on the test) Which letter represents an organism that could only be a primary consumer?

C

1) A population is correctly defined as having which of the following characteristics? I. inhabiting the same general area II. individuals belonging to the same species III. possessing a constant and uniform density and dispersion A) I only B) III only C) I and II only D) II and III only E) I, II, and III

C

1) The observation that members of a population are uniformly distributed suggests that A) the size of the area occupied by the population is increasing. B) resources are distributed unevenly. C) the members of the population are competing for access to a resource. D) the members of the population are neither attracted to nor repelled by one another. E) the density of the population is low.

C

17) In order to construct a reproductive table for a sexual species, you need to A) assess sperm viability. B) keep track of all of the offspring of a cohort. C) keep track of the females in a cohort. D) keep track of all of the offspring of the females in a cohort. E) keep track of the ratio of deaths to births in a cohort.

C

2) Population ecologists follow the fate of same-age cohorts to A) determine a populationʹs carrying capacity. B) determine if a population is regulated by density-dependent processes. C) determine the birth rate and death rate of each group in a population. D) determine the factors that regulate the size of a population. E) determine if a populationʹs growth is cyclic.

C

21) Long-term studies of Beldingʹs ground squirrels show that immigrants move nearly 2 km from where they are born and make up 1 to 8% of the males and 0.7 to 6% of the females in other populations. On an evolutionary scale, why is this significant? A) These immigrants make up for the deaths of individuals keeping the other populationsʹ size stable. B) Young reproductive males tend to stay in their home population and are not driven out by other territorial males. C) These immigrants provide a source of genetic diversity for the other populations. D) Those individuals that emigrate to these new populations are looking for less crowded conditions with more resources. E) Gradually, the populations of ground squirrels will move from a uniform to a clumped population pattern of dispersion.

C

25) The three basic variables that make up the life history of an organism are A) life expectancy, birth rate, and death rate. B) number of reproductive females in the population, age structure of the population, and life expectancy. C) age when reproduction begins, how often reproduction occurs, and how many offspring are produced per reproductive episode. D) how often reproduction occurs, life expectancy of females in the population, and number of offspring per reproductive episode. E) the number of reproductive females in the population, how often reproduction occurs, and death rate.

C

60) A population of white-footed mice becomes severely overpopulated in a habitat that has been disturbed by human activity. Sometimes intrinsic factors cause the population to increase in mortality and lower reproduction rates in reaction to the stress of overpopulation. Which of the following is an example of intrinsic population control? A) Owl populations frequent the area more often because of increased hunting success. B) Females undergo hormonal changes that delay sexual maturation and many individuals suffer depressed immune systems and die due to the stress of overpopulation. C) Clumped dispersion of the population leads to increased spread of disease and parasites resulting in a population crash. D) All of the resources (food and shelter) are used up by overpopulation and much of the population dies of exposure and/or starvation. E) Because the individuals are vulnerable they are more likely to die off if a drought or flood were to occur.

C

67) Most ecologists believe that the average global carrying capacity for the human population is between A) 5 and 6 billion. B) 6 and 8 billion. C) 10 and 15 billion. D) 15 and 20 billion. E) 20 and 25 billion.

C

7) Scientific study of the population cycles of the snowshoe hare and its predator, the lynx, has revealed that A) the prey population is controlled by predators alone. B) hares and lynx are so mutually dependent that each species cannot survive without the other. C) multiple biotic and abiotic factors contribute to the cycling of hare and lynx populations. D) both hare and lynx populations are regulated mainly by abiotic factors. E) the hare population is r-selected and the lynx population is K-selected.

C

9) Which of the following statements about human population in industrialized countries is incorrect? A) Average family size is relatively small. B) The population has undergone the demographic transition. C) Life history is r-selected. D) The survivorship curve is Type I. E) Age distribution is relatively uniform.

C

The Hubbard Brook watershed deforestation experiment yielded all of the following results except: Calcium levels remained high in the soil of deforested areas. The flow of minerals out of a natural watershed was offset by minerals flowing in. Deforestation increased water runoff. Most minerals were recycled within a forest ecosystem. The nitrate concentration in waters draining the deforested area became dangerously high.

Calcium levels remained high in the soil of deforested areas.

In cross-fostering studies, the young of one species are placed in the care of adults from another species. In broad terms, what do researchers learn from such studies? Select all that apply. Changes in the behavior of cross-fostered young provide information about how the social and physical environment influences behavior. Cross-fostering studies provide information about the relative importance of nature and nurture in the development of a trait. Cross-fostering studies provide information about the evolutionary relationship between the two species.

Changes in the behavior of cross-fostered young provide information about how the social and physical environment influences behavior. Cross-fostering studies provide information about the relative importance of nature and nurture in the development of a trait.

The majority of young, inexperienced Western garter snakes born in the laboratory from mothers captured in coastal areas of California readily eat pieces of slug. What are plausible proximate explanations for this behavior? Select all that apply. Coastal snakes can detect odor molecules produced by banana slugs. Coastal snakes have a genetically acquired taste for banana slugs. Coastal snakes that readily eat banana slugs gain most of their calories from this prey species.

Coastal snakes can detect odor molecules produced by banana slugs. Coastal snakes have a genetically acquired taste for banana slugs.

10) A recent study of ecological footprints (described in the text) concluded that A) Earthʹs carrying capacity for humans is about 10 billion. B) Earthʹs carrying capacity would increase if per capita meat consumption increased. C) current demand by industrialized countries for resources is much smaller than the ecological footprint of those countries. D) the ecological footprint of the United States is large because per capita resource use is high. E) it is not possible for technological improvements to increase Earthʹs carrying capacity for humans.

D

19) To measure the population of lake trout in a 250 hectare lake, 200 individuals were netted and marked with a fin clip, and then returned to the lake. The next week, the lake is netted again, and out of the 200 lake trout that are caught, 50 have fin clips. Using the capture-recapture estimate, the lake trout population size could be closest to which of the following? A) 200 B) 250 C) 400 D) 800 E) 40,000

D

23) Natural selection has led to the evolution of diverse natural history strategies, which have in common A) many offspring per reproductive episode. B) limitation only by density-independent limiting factors. C) adaptation to stable environments. D) maximum lifetime reproductive success. E) relatively large offspring.

D

Researchers in the Netherlands studied the effects of parental caregiving in European kestrels over 5 years. The researchers transferred chicks among nests to produce reduced broods (three or four chicks), normal broods (five or six), and enlarged broods (seven or eight). They then measured the percentage of male and female parent birds that survived the following winter. (Both males and females provide care for chicks.) 26) Which of the following is a conclusion that can be drawn from this graph? A) Female survivability is more negatively affected by larger brood size than is male survivability. B) Male survivability decreased by 50% between reduced and enlarged brood treatments. C) Both males and females had increases in daily hunting with the enlarged brood size. D) There appears to be a negative correlation between brood enlargements and parental survival. E) Chicks in reduced brood treatment received more food, weight gain, and reduced mortality.

D

Gray wolves, once the top predators in Yellowstone National Park, were hunted to extinction there in 1926. In 1995, 15 wolves were brought to Yellowstone from Alberta. The wolf population has now grown to 300. The forest community in Yellowstone National Park can be described by a top-down model of community organization. Wolves hunt and eat elk. Elk are herbivores that prefer riparian vegetation (plants growing next to streams and lakes). Ravens, bears, and eagles feed on elk carcasses. How would you expect the return of the wolves to Yellowstone to affect the other species there? Select all that apply. Riparian vegetation would decline. Elk populations would decline. Bear populations would decline.

Elk populations would decline.

Select the correct statement about the global carrying capacity for the human population. The global carrying capacity for the human population is limitless because technological advances allow food supply to keep up with global population growth. Estimates of the global carrying capacity for the human population depend on resource use per capita. It is impossible to calculate the global carrying capacity for the human population.

Estimates of the global carrying capacity for the human population depend on resource use per capita.

Which of the following is true with respect to oligotrophic lakes and eutrophic lakes? Sediments in oligotrophic lakes contain larger amounts of decomposable organic matter. Eutrophic lake water contains lower concentrations of nutrients. Rates of photosynthesis are lower in eutrophic lakes. Eutrophic lakes are richer in nutrients. Oligotrophic lakes are more subject to oxygen depletion.

Eutrophic lakes are richer in nutrients.

The correct answer: A

Ground tissue is indicated by the letter _____.

Why do moderate levels of disturbance result in an increase in community diversity?

Habitats are opened up for less competitive species.

(Refer to graph on the test) Which mortality curve indicated that the probability of death is equal at any age?

II

(Refer to figure on the test) Which population is in the process of decreasing?

III

...

Identify A

...

Identify B

Polar Nuclei

Identify C

...

Identify D

...

Identify E

Select the correct statement about the factors that limit the growth of a population. Density-dependent factors are biotic; density-independent factors are abiotic. The most important factor limiting population growth is the scarcest factor in that area. If a factor limits population growth, increasing its availability will increase population growth.

If a factor limits population growth, increasing its availability will increase population growth.

Which of the following is not required for a behavioral trait to evolve by natural selection? An individual's reproductive success depends in part on how the behavior is performed. In each individual, the form of the behavior is determined entirely by genes. An individual's genotype influences its behavioral phenotype. The behavior varies among individuals. Some component of the behavior is genetically inherited.

In each individual, the form of the behavior is determined entirely by genes.

Which statement accurately describes the potential effects of disturbance on species diversity? Moderate levels of disturbance generally act to reduce species diversity within a community. In many biomes, periodic disturbances may eliminate the dominant plants. Many species are well adapted to survive periodic disturbances.

Many species are well adapted to survive periodic disturbances.

Identify the correct statement(s) about sensory receptors. Select all that apply. Mechanoreceptors detect sound. Foods taste spicy when they activate the same sensory receptors that high temperatures activate. Electromagnetic receptors detect pheromones.

Mechanoreceptors detect sound. Foods taste spicy when they activate the same sensory receptors that high temperatures activate.

In mammals, the eardrum transmits sound waves to three small bones, which transmit the waves to fluid waves within the cochlea. Where are the three small bones located? Middle ear Outer ear Inner ear

Middle ear

What is a likely outcome of a moderate disturbance, such as a severe thunderstorm? Select all that apply. Reduced species diversity within a community Patches of different habitats within the landscape Loss of an equilibrium state of balance, leading to a less healthy community

Patches of different habitats within the landscape

E

Pith is indicated by the letter _____.

The correct answer: A

Primary growth has occurred in the region(s) indicated by the letter(s) _____.

Identify the role(s) of ATP in muscle contraction. Select all that apply. Provides the energy to convert myosin to a form that forms a cross-bridge with actin Binds to myosin to break an actin-myosin cross-bridge Binds to the troponin complex to expose myosin-binding sites

Provides the energy to convert myosin to a form that forms a cross-bridge with actin Binds to myosin to break an actin-myosin cross-bridge

(Refer to the graph on the test) What does the graph in the figure above tell you about the definition of a keystone species?

Removing a keystone species from the community drastically reduces diversity.

The graph shows the growth of a laboratory culture of Paramecium aurelia. After 15 days, the researcher removed ~400 paramecia from the culture. How will the population growth rate (dN/dt) change as a result of this action? The growth rate of the Paramecium population will decrease. The growth rate of the Paramecium population will increase. The growth rate of the Paramecium population will not change.

The growth rate of the Paramecium population will increase.

Nitrifying bacteria participate in the nitrogen cycle mainly by incorporating nitrogen into amino acids and organic compounds. converting ammonia to nitrogen gas, which returns to the atmosphere. converting nitrogen gas to ammonia. converting ammonium to nitrate, which plants absorb. releasing ammonium from organic compounds, thus returning it to the soil.

converting ammonium to nitrate, which plants absorb.

Plasma membranes of adjacent cardiac muscle cells interlock at specialized regions called intercalated disks. What is the significance of this feature of cardiac muscles? The intercalated disks play the same role as striations of skeletal muscle. The intercalated disks generate action potentials within the heart muscle without nervous system input. The intercalated disks allow coordinated contraction of the whole heart.

The intercalated disks allow coordinated contraction of the whole heart.

Select the correct statement(s) about the transfer of food energy up the trophic levels from its source in autotrophs. Select all that apply. Few plants have adaptations to reduce feeding by herbivores. The length of a food chain is limited by the inefficiency of energy transfer along the chain. An organism feeds at only one trophic level.

The length of a food chain is limited by the inefficiency of energy transfer along the chain

The correct answer: secondary xylem

The letter A indicates _____.

cortex

The letter A indicates the _____.

The correct answer: epidermis

The letter A indicates_________

Sensory pathways have four basic functions: sensory reception, transduction, transmission, and perception. How do these functions differ between yourself and a star-nosed mole? Select all that apply. Select all that apply. The perception of sensory input by humans and star-nosed moles differs. The mechanism by which the energy of a sensory stimulus is transduced into a receptor potential differs between humans and star-nosed moles. The number and type of sensory receptors in humans and star-nosed moles differ.

The perception of sensory input by humans and star-nosed moles differs. The number and type of sensory receptors in humans and star-nosed moles differ.

The correct answer: D

The region surrounded by guard cells is indicated by the letter _____.

(Refer to the figure on the test) What conclusion can you draw from the figure above?

The relationship between the populations cannot be determined only from this graph.

What would be the effect on climate in the temperate latitudes if Earth were to slow its rate of rotation from a 24-hour period of rotation to a 48-hour period of rotation?

There often would be a larger range between daytime high and nighttime low temperatures.

Which of the following is true of innate behaviors? Their expression is only weakly influenced by genes. They are expressed in most individuals in a population. They occur in invertebrates and some vertebrates but not mammals. They are limited to invertebrate animals. They occur with or without environmental stimuli.

They are expressed in most individuals in a population

Graylag goslings imprint on a nearby object that moves away from them during a sensitive period in the first few hours after they hatch, and follow the object steadfastly from that time on. What is the adaptive value of this behavior? This behavior is not adaptive because goslings may imprint on objects other than their parents. This behavior is likely to increase gosling survival. This behavior is genetic.

This behavior is likely to increase gosling survival.

How do pyramids of net production and pyramids of biomass differ? Pyramids of net production include fewer trophic levels than pyramids of biomass. Unlike pyramids of biomass, pyramids of net production are based on measurements per unit time. Unlike pyramids of net production, the shape of a pyramid of biomass varies with the size of the organisms in the ecosystem.

Unlike pyramids of biomass, pyramids of net production are based on measurements per unit time.

In Australia, researchers tested the hypothesis that sea urchin abundance limits kelp distribution. Select the evidence that offers the best support for this hypothesis. There is an inverse relationship between the abundance of sea urchins and the abundance of kelp. When sea urchins were removed from experimental plots, kelp cover increased. Sea urchins graze on kelp.

When sea urchins were removed from experimental plots, kelp cover increased.

C

Which population appears to be stable? a. I b. II c. III d. I and II e. II and III

B

Which population is in the process of decreasing? a. I b. II c. III d. I and II e. II and III

What would happen to the seasons if the Earth were tilted 35 degrees off its orbital plane instead of the usual 23.5 degrees?

Winters and summers would be more severe.

D

Xylem is indicated by the letter _____

Elephants are not the most dominant species in African grasslands, yet they influence community structure. The grasslands contain scattered woody plants, but they are kept in check by the uprooting activities of the elephants. Take away the elephants, and the grasslands convert to forests or to shrubs. The newly growing forests support fewer species that the previous grasslands. Which of the following describes why elephants are the keystone species in this scenario? a) Elephants exhibit a disproportionate influence on the structure of the community relative to their abundance. b) Grazing animals depend upon the elephants to convert forests to grassland. c) Elephants are the biggest herbivore in this community. d) Elephants help other populations survive by keeping out many of the large African predators.

a) Elephants exhibit a disproportionate influence on the structure of the community relative to their abundance.

According to the bottom-up and top-down control models of community organization, which of the following expressions would imply that an increase in the size of a carnivore (C) population would negatively impact its prey (P) population, but not vise versa? a) P < C b) P > C c) C <> P d) P < C > P

a) P < C

Density independent population controls include all of the following EXCEPT... a) Resource competition b) Drought c) Fire d) Climate change

a) Resource competition

Which of the following would be considered an example of bioremediation? reconfiguring the channel of a river using a bulldozer to regrade a strip mine adding seeds of a chromium-accumulating plant to soil contaminated by chromium dredging a river bottom to remove contaminated sediments adding nitrogen-fixing microorganisms to a degraded ecosystem to increase nitrogen availability

adding nitrogen-fixing microorganisms to a degraded ecosystem to increase nitrogen availability

A region of the canary forebrain shrinks during the nonbreeding season and enlarges when breeding season begins. This change is probably associated with the annual renewal of mating and nest-building behaviors. sensitive period in which canary parents imprint on new offspring. addition of new syllables to a canary's song repertoire. crystallization of subsong into adult songs. elimination of the memorized template for songs sung the previous year.

addition of new syllables to a canary's song repertoire.

The middle ear converts air pressure waves to fluid pressure waves. fluid pressure waves to nerve impulses. air pressure waves to nerve impulses. fluid pressure waves to air pressure waves. pressure waves to hair cell movements.

air pressure waves to fluid pressure waves.

Which of these ecosystems has the lowest net primary production per square meter? a tropical rain forest a salt marsh an open ocean a grassland a coral reef

an open ocean

Which lake zone would be absent in a very shallow lake? aphotic zone pelagic zone limnetic zone littoral zone benthic zone

aphotic zone

During the contraction of a vertebrate skeletal muscle fiber, calcium ions spread action potentials through the T tubules. break cross-bridges by acting as a cofactor in the hydrolysis of ATP. transmit action potentials from the motor neuron to the muscle fiber. re-establish the polarization of the plasma membrane following an action potential. bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed.

bind with troponin, changing its shape so that the myosin-binding sites on actin are exposed.

In which of the following situations would you expect to find the largest number of K-selected individuals? a) Recently abandoned agricultural field in Ohio b) A shifting sand dune community of south Lake Michigan c) An old-growth forest d) South Florida after a hurricane

c) An old-growth forest

Which of the following statements is consistent with the principle of competitive exclusion? a) The random distribution of one competing species will have a positive impact on the population growth of the other competing species. b) Two species with the same fundamental niche will exclude other competing species. c) Even a slight reproductive advantage will eventually lead to the elimination of the less well adapted of the two competing species. d) Natural selection tends to increase competition between related species.

c) Even a slight reproductive advantage will eventually lead to the elimination of the less well adapted of the two competing species.

Which of the following could qualify as a top-down control on a grassland community? limitation of plant biomass by rainfall amount effect of humidity on plant growth rates effect of grazing intensity by bison on plant species diversity influence of temperature on competition among plants influence of soil nutrients on the abundance of grasses versus wildflowers

effect of grazing intensity by bison on plant species diversity