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317 terms

Combo with Unit 6 Mastering Biology and 5 others

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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
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.
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.
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
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
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.
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
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.
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.
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
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
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.
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
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.
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.
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.
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.
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.
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.
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.
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.
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
Which lake zone would be absent in a very shallow lake?

aphotic zone
pelagic zone
limnetic zone
littoral zone
benthic zone
aphotic zone
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.
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
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
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.
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.
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.
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
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.
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.
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.
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.
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.
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
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.
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.
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
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.
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.
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.
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
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.
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.
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.
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.
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.
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.
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.
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
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.
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.
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.
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.
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.
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
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.
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.
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.
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
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
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.
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
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
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.
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.
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 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.
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
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.
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.
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.
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 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.
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.
Unlike an earthworm's metanephridia, a mammalian nephron

functions in both osmoregulation and excretion.
is intimately associated with a capillary network.
forms urine by changing fluid composition inside a tubule.
has a transport epithelium.
receives filtrate from blood instead of coelomic fluid.
receives filtrate from blood instead of coelomic fluid.
Which process in the nephron is least selective?

secretion
salt pumping by the loop of Henle
reabsorption
active transport
filtration
filtration
which of the following animals generally has the lowest volume of urine production?

a shark inhabiting freshwater Lake Nicaragua
a marine bony fish
a freshwater bony fish
a vampire bat
a salmon in fresh water
a marine bony fish
The high osmolarity of the renal medulla is maintained by all of the following except

diffusion of salt from the descending limb of the loop of Henle.
the spatial arrangement of juxtamedullary nephrons.
diffusion of salt from the thin segment of the ascending limb of the loop of Henle.
active transport of salt from the upper region of the ascending limb.
diffusion of urea from the collecting duct.
diffusion of salt from the descending limb of the loop of Henle.
Natural selection should favor the highest proportion of juxtamedullary nephrons in which of the following species?

a beaver
a river otter
a mouse species living in a desert
a mouse species living in a temperate broadleaf forest
a mouse species living in a tropical rain forest
a mouse species living in a desert
African lungfish, which are often found in small stagnant pools of fresh water, produce urea as a nitrogenous waste. What is the advantage of this adaptation?

The highly toxic urea makes the pool uninhabitable to potential competitors.
Urea takes less energy to synthesize than ammonia.
Urea forms an insoluble precipitate.
Urea makes lungfish tissue hypoosmotic to the pool.
Small stagnant pools do not provide enough water to dilute the toxic ammonia.
Small stagnant pools do not provide enough water to dilute the toxic ammonia.
Which of the following is not an accurate statement?

Hormones of the same chemical class usually have the same function.
Hormones are chemical messengers that travel to target cells through the circulatory system.
Hormones are often regulated through feedback loops.
Hormones are secreted by specialized cells usually located in endocrine glands.
Hormones often regulate homeostasis through antagonistic functions.
Hormones of the same chemical class usually have the same function.
An example of antagonistic hormones controlling homeostasis is

epinephrine and norepinephrine in fight-or-flight responses.
progestins and estrogens in sexual differentiation.
oxytocin and prolactin in milk production.
thyroxine and parathyroid hormone in calcium balance.
insulin and glucagon in glucose metabolism.
insulin and glucagon in glucose metabolism.
Growth factors are local regulators that

bind to cell-surface receptors and stimulate growth and development of target cells.
are modified fatty acids that stimulate bone and cartilage growth.
are produced by the anterior pituitary.
convey messages between nerve cells.
are found on the surface of cancer cells and stimulate abnormal cell division.
bind to cell-surface receptors and stimulate growth and development of target cells.
Which hormone is incorrectly paired with its action?

ACTH-stimulates the release of glucocorticoids by the adrenal cortex
melatonin-affects biological rhythms, seasonal reproduction
insulin-stimulates glycogen breakdown in the liver
oxytocin-stimulates uterine contractions during childbirth
thyroxine-stimulates metabolic processes
insulin-stimulates glycogen breakdown in the liver
Steroid and peptide hormones typically have in common

the location of their receptors.
their requirement for travel through the bloodstream.
their reliance on signal transduction in the cell.
their solubility in cell membranes.
the building blocks from which they are synthesized.
their requirement for travel through the bloodstream.
Which of the following is the most likely explanation for hypothyroidism in a patient whose iodine level is normal?

a decrease in the thyroid secretion of calcitonin
hypersecretion of TSH
hypersecretion of MSH
hyposecretion of TSH
greater production of T3 than of T4
hyposecretion of TSH
Shortly after ingesting a big plate of carbohydrate-rich pasta, you measure your blood's hormone levels. What results would you expect, compared to before the meal?

low insulin, low glucagon
high insulin, low glucagon
low insulin, high glucagon
high insulin, high glucagon
low insulin, no change in glucagon
high insulin, low glucagon
The relationship between the insect hormones ecdysteroid and PTTH is an example of

competitive inhibition of a hormone receptor.
how peptide-derived hormones have more widespread effects than steroid hormones.
an interaction of the endocrine and nervous systems.
homeostasis achieved by positive feedback.
homeostasis maintained by antagonistic hormones.
an interaction of the endocrine and nervous systems.
Which of the following characterizes parthenogenesis?

Specialized groups of cells grow into new individuals.
Both mates have male and female reproductive organs.
An egg develops without being fertilized.
An organism is first a male and then a female.
An individual may change its sex during its lifetime.
An egg develops without being fertilized.
In male mammals, excretory and reproductive systems share

the urethra.
the testes.
the vas deferens.
the seminal vesicle.
the prostate.
the urethra
Which of the following is not properly paired?

vas deferens-oviduct
seminiferous tubule-cervix
scrotum-labia majora
testosterone-estradiol
Sertoli cells-follicle cells
seminiferous tubule-cervix
Peaks of LH and FSH production occur during

the end of the luteal phase of the ovarian cycle.
the menstrual flow phase of the uterine cycle.
the beginning of the follicular phase of the ovarian cycle.
the secretory phase of the menstrual cycle.
the period just before ovulation.
the period just before ovulation.
During human gestation, rudiments of all organs develop

in the second trimester.
while the embryo is in the oviduct.
in the third trimester.
during the blastocyst stage.
in the first trimester.
in the first trimester.
Which of the following is a true statement?

The endometrial lining is shed in menstrual cycles but reabsorbed in estrous cycles.
All mammals have menstrual cycles.
Ovulation occurs before the endometrium thickens in estrous cycles.
Estrous cycles are not controlled by hormones.
Estrous cycles are more frequent than menstrual cycles.
The endometrial lining is shed in menstrual cycles but reabsorbed in estrous cycles.
For which of the following is the number the same in spermatogenesis and oogenesis?

gametes produced in a given time period
functional gametes produced by meiosis
interruptions in meiotic divisions
different cell types produced by meiosis
meiotic divisions required to produce each gamete
meiotic divisions required to produce each gamete
Which statement about human reproduction is false?

An oocyte completes meiosis after a sperm penetrates it.
Spermatogenesis and oogenesis require different temperatures.
Effective hormonal contraceptives are currently available only for females.
Fertilization occurs in the oviduct.
The earliest stages of spermatogenesis occur closest to the lumen of the seminiferous tubules.
The earliest stages of spermatogenesis occur closest to the lumen of the seminiferous tubules.
The cortical reaction of sea urchin eggs functions directly in

the generation of an electrical impulse by the egg.
the production of a fast block to polyspermy.
the release of hydrolytic enzymes from the sperm.
the formation of a fertilization envelope.
the fusion of egg and sperm nuclei.
the formation of a fertilization envelope.
Which of the following is common to the development of both birds and mammals?

epiblast and hypoblast
trophoblast
yolk plug
holoblastic cleavage
gray crescent
epiblast and hypoblast
The archenteron develops into

the mesoderm.
the blastocoel.
the lumen of the digestive tract.
the endoderm.
the placenta.
the lumen of the digestive tract.
What structural adaptation in chickens allows them to lay their eggs in arid environments rather than in water?

development of the brain from ectoderm
cleavage
gastrulation
extraembryonic membranes
yolk
extraembryonic membranes
In an egg cell treated with EDTA, a chemical that binds calcium and magnesium ions,

the fusion of sperm and egg nuclei would be blocked.
the acrosomal reaction would be blocked.
the fast block to polyspermy would not occur.
the fertilization envelope would not form.
the zygote would not contain maternal and paternal chromosomes.
the fertilization envelope would not form.
In humans, identical twins are possible because

early blastomeres can form a complete embryo if isolated.
cytoplasmic determinants are distributed unevenly in unfertilized eggs.
convergent extension occurs.
extraembryonic cells interact with the zygote nucleus.
the gray crescent divides the dorsal-ventral axis into new cells.
early blastomeres can form a complete embryo if isolated.
Cells transplanted from the neural tube of a frog embryo to the ventral part of another embryo develop into nervous system tissues. This result indicates that the transplanted cells were

mesenchymal.
determined.
apoptotic.
differentiated.
totipotent.
determined.
In an embryonic vertebrate, the apical ectodermal ridge (AER) is a thickened area at the tip of the bud. The cells of the AER secrete protein signals that promote limb-bud outgrowth, and removing the AER blocks growth of the limb along the proximal-distal axis. How would the forelimb of an embryo develop if the AER was removed early or late in limb development?

Early removal of the AER would prevent the formation of many distal structures, whereas late removal of the AER would prevent the formation of a few distal structures.
Early or late removal of the AER would have the same result: the embryo would not develop a forelimb.
Early removal of the AER would prevent the development of a forelimb, whereas late removal of the AER would not have any effect.
Early removal of the AER would prevent the formation of many distal structures, whereas late removal of the AER would prevent the formation of a few distal structures.
Select the correct statement about embryonic development in a frog.

Development from zygote to blastula involves mitotic division, cell movement, and cell growth.
The blastocoel of a developing frog embryo develops into the digestive tract.
The reorganization of cell layers during gastrulation allows the layers to interact with each other in new ways.
The reorganization of cell layers during gastrulation allows the layers to interact with each other in new ways.
The allantois stores nitrogenous wastes in a reptile egg. What is the function of the allantois in human development?

The allantois does not play any role in human development, because the placenta mediates the transfer of nitrogenous wastes from embryonic to maternal circulation.
The allantois helps form the umbilical cord in human development.
The allantois cushions the human embryo in a private "pond" during development.
The allantois helps form the umbilical cord in human development.
Identify the correct statement(s) about Spemann's organizer.
Select all that apply.

Spemann's organizer is the dorsal lip of the blastopore in frog gastrulation.
Spemann's organizer initiates a chain of inductive interactions in frog development.
Spemann's organizer is made up of totipotent cells.
Spemann's organizer is the dorsal lip of the blastopore in frog gastrulation.
Spemann's organizer initiates a chain of inductive interactions in frog development.
In an embryonic vertebrate, the zone of polarizing activity (ZPA) is a block of tissue located on the posterior side of a limb bud. The ZPA provides information about the anterior-posterior axis of the limb. Cells nearest the ZPA form the most posterior of digits (like our little finger); cells farthest from the ZPA form the most anterior digits (like our thumb).

How would a vertebrate forelimb bud develop if it had two zones of polarizing activities, one on the posterior side and one on the anterior side of the bud?

The forelimb bud would develop into a hind limb.
The embryo wouldn't develop a forelimb.
The forelimb bud would develop with extra digits, in a mirror image arrangement to the normal digits.
The forelimb bud would develop with extra digits, in a mirror image arrangement to the normal digits.
What happens when a resting neuron's membrane depolarizes?

There is a net diffusion of Na+ out of the cell.
The equilibrium potential for K+ (E K) becomes more positive.
The neuron's membrane voltage becomes more positive.
The cell's inside is more negative than the outside.
The neuron is less likely to generate an action potential.
The neuron's membrane voltage becomes more positive.
A common feature of action potentials is that they

cause the membrane to hyperpolarize and then depolarize.
move at the same speed along all axons.
are triggered by a depolarization that reaches the threshold.
require the diffusion of and through ligand-gated channels to propagate.
can undergo temporal and spatial summation.
are triggered by a depolarization that reaches the threshold.
Where are neurotransmitter receptors located?

synaptic vesicle membranes
the postsynaptic membrane
the nuclear membrane
the myelin sheath
the nodes of Ranvier
the postsynaptic membrane
Temporal summation always involves

inputs that are not simultaneous.
synapses at more than one site.
both inhibitory and excitatory inputs.
multiple inputs at a single synapse.
electrical synapses.
multiple inputs at a single synapse.
Why are action potentials usually conducted in one direction?

Voltage-gated channels for both Na+ and K+ open in only one direction.
The brief refractory period prevents reopening of voltage-gated Na+ channels.
Ions can flow along the axon in only one direction.
The axon hillock has a higher membrane potential than the terminals of the axon.
The nodes of Ranvier conduct potentials in one direction.
The brief refractory period prevents reopening of voltage-gated Na+ channels.
Which of the following is a direct result of depolarizing the presynaptic membrane of an axon terminal?

An EPSP or IPSP is generated in the postsynaptic cell.
The postsynaptic cell produces an action potential.
Ligand-gated channels open, allowing neurotransmitters to enter the synaptic cleft.
Synaptic vesicles fuse with the membrane.
Voltage-gated calcium channels in the membrane open.
Voltage-gated calcium channels in the membrane open.
Why is an action potential an all-or-none response to stimuli?

Because a typical neuron receives signals through multiple dendrites but transmits signals through a single axon
Because neurons contain gated ion channels that are either open or closed
Because voltage-gated ion channels open when membrane potential passes a particular level
Because voltage-gated ion channels open when membrane potential passes a particular level
What causes the falling phase of the action potential? Select the best answer.

The opening of voltage-gated sodium channels
Inactivation of voltage-gated sodium channels and the opening of voltage-gated potassium channels
The opening of voltage-gated potassium channels
Inactivation of voltage-gated sodium channels and the opening of voltage-gated potassium channels
If the membrane potential of a neuron decreases, the membrane potential _____.

remains unchanged.
becomes more negative.
becomes more positive.
becomes more positive.
The plasma membrane of a neuron has voltage-gated sodium and potassium channels. What is the effect of membrane depolarization on these channels?

Membrane depolarization opens sodium and potassium channels at the same time.
Membrane depolarization first opens sodium channels and then opens potassium channels.
Membrane depolarization opens sodium channels but closes potassium channels.
Membrane depolarization first opens sodium channels and then opens potassium channels.
Identify the correct statement(s) about the resting membrane potential of a cell.
Select all that apply.

Potassium (K+) and sodium (Na+) gradients are maintained by active transport in a resting mammalian neuron.
Neurons are the only cells that have a charge difference across their membranes.
Concentration gradients of potassium (K+) and sodium (Na+) across the plasma membrane represent potential energy.
Potassium (K+) and sodium (Na+) gradients are maintained by active transport in a resting mammalian neuron.
Concentration gradients of potassium (K+) and sodium (Na+) across the plasma membrane represent potential energy.
Wakefulness is regulated by the reticular formation, which is present in the

spinal cord.
limbic system.
basal nuclei.
cerebral cortex.
brainstem.
brainstem.
Which of the following structures or regions is incorrectly paired with its function?

corpus callosum-communication between the left and right cerebral cortices
amygdala-emotional memory
limbic system-motor control of speech
medulla oblongata-homeostatic control
cerebellum-coordination of movement and balance
limbic system-motor control of speech
Patients with damage to Wernicke's area have difficulty

coordinating limb movement.
generating speech.
experiencing emotion.
understanding language.
recognizing faces.
understanding language.
The cerebral cortex plays a major role in all of the following except

foot-tapping rhythm.
long-term memory.
circadian rhythm.
short-term memory.
breath holding.
circadian rhythm.
After suffering a stroke, a patient can see objects anywhere in front of him but pays attention only to objects in his right field of vision. When asked to describe these objects, he has difficulty judging their size and distance. What part of the brain was likely damaged by the stroke?

the corpus callosum
the left parietal lobe
the right frontal lobe
the left frontal lobe
the right parietal lobe
the right parietal lobe
Injury localized to the hypothalamus would most likely disrupt

executive functions, such as decision making.
short-term memory.
coordination during locomotion.
regulation of body temperature.
sorting of sensory information.
regulation of body temperature.
Identify the role(s) of glia in the vertebrate brain.
Select all that apply.

Glia release neurotransmitters.
Glia protect the nervous system from pathogens.
Glia guide neuron migration during development of the CNS
Glia release neurotransmitters.
Glia protect the nervous system from pathogens.
Glia guide neuron migration during development of the CNS
Which examples correctly illustrate the cooperation between the motor and nervous systems to maintain homeostasis in a vertebrate body?
Select all that apply.

A drop in body temperature leads to shivering and constriction of surface blood vessels.
In response to a sudden fright, the body responds by increasing heart rate, inhibiting digestion, and increasing blood glucose.
If you put your hand on a hot burner, a reflex pulls your hand back before you sense pain.
A drop in body temperature leads to shivering and constriction of surface blood vessels.
Which of these observations illustrate the developmental plasticity of the human nervous system?
Select all that apply.

When activity at a synapse correlates with the activity of other synapses, that synaptic connection is reinforced.
A person suffering from phantom limb pain following amputation may stop feeling pain after viewing a reflection of the remaining limb in a mirrored box.
The brain may ignore certain stimuli and actively process other stimuli.
When activity at a synapse correlates with the activity of other synapses, that synaptic connection is reinforced.
A person suffering from phantom limb pain following amputation may stop feeling pain after viewing a reflection of the remaining limb in a mirrored box.
Identify the correct statement(s) about glial cells and their functions.
Select all that apply.

Oligodendrocytes act as stem cells, producing neurons and glia.
Schwann cells myelinate dendrites in the PNS.
Astrocytes induce the formation of the blood-brain barrier.
Astrocytes induce the formation of the blood-brain barrier.
Which of these observations illustrate regional specialization in the human nervous system?
Select all that apply.

Reading a printed word out loud and then thinking of a related word involves the visual cortex, Broca's area, and the frontal and temporal lobes.
Sensory information may be processed in the occipital lobe or the temporal lobe.
When the activity of a synapse fails to correlate with that of other synapses, the synaptic connection may become weaker.
Reading a printed word out loud and then thinking of a related word involves the visual cortex, Broca's area, and the frontal and temporal lobes.
Sensory information may be processed in the occipital lobe or the temporal lobe.
Vertebrates and tunicates share

a notochord and a dorsal, hollow nerve cord.
an endoskeleton that includes a skull.
jaws adapted for feeding.
the formation of structures from the neural crest.
a high degree of cephalization.
a notochord and a dorsal, hollow nerve cord.
Some animals that lived 530 million years ago resembled lancelets but had a brain and a skull. These animals may represent

marsupials.
a "missing link" between urochordates and cephalochordates.
the first chordates.
nontetrapod gnathostomes.
early craniates.
early craniates.
Which of the following could be considered the most recent common ancestor of living tetrapods?

an early ray-finned fish that developed bony skeletal supports in its paired fins
a sturdy-finned, shallow-water lobe-fin whose appendages had skeletal supports similar to those of terrestrial vertebrates
an early terrestrial caecilian whose legless condition had evolved secondarily
an armored, jawed placoderm with two pairs of appendages
a salamander that had legs supported by a bony skeleton but moved with the side-to-side bending typical of fishes
a sturdy-finned, shallow-water lobe-fin whose appendages had skeletal supports similar to those of terrestrial vertebrates
Unlike eutherians, both monotremes and marsupials

lay eggs.
lack nipples.
have some embryonic development outside the uterus.
include only insectivores and herbivores.
are found in Australia and Africa.
have some embryonic development outside the uterus.
Which clade does not include humans?

synapsids
diapsids
craniates
lobe-fins
osteichthyans
diapsids
As hominins diverged from other primates, which of the following appeared first?

language
reduced jawbones
the making of stone tools
an enlarged brain
bipedal locomotion
bipedal locomotion
The body tissue that consists largely of material located outside of cells is

skeletal muscle.
nervous tissue.
smooth muscle.
connective tissue.
epithelial tissue.
connective tissue.
Which of the following would increase the rate of heat exchange between an animal and its environment?

feathers or fur
wind blowing across the body surface
blubber or fat layer
vasoconstriction
countercurrent heat exchanger
wind blowing across the body surface
Consider the energy budgets for a human, an elephant, a penguin, a mouse, and a snake. The __________ would have the highest total annual energy expenditure, and the __________ would have the highest energy expenditure per unit mass.

elephant; mouse
elephant; human
penguin; mouse
mouse; snake
human; penguin
elephant; mouse
Compared with a smaller cell, a larger cell of the same shape has

less surface area.
the same surface-to-volume ratio.
a smaller average distance between its mitochondria and the external source of oxygen.
a smaller cytoplasm-to-nucleus ratio.
less surface area per unit of volume.
less surface area per unit of volume.
An animal's inputs of energy and materials would exceed its outputs

if the animal is an endotherm, which must always take in more energy because of its high metabolic rate.
if it is hibernating.
never; homeostasis makes these energy and material budgets always balance.
if it is actively foraging for food.
if it is growing and increasing its mass.
if it is growing and increasing its mass.
You are studying a large tropical reptile that has a high and relatively stable body temperature. How would you determine whether this animal is an endotherm or an ectotherm?

You know from its high and stable body temperature that it must be an endotherm.
You note that its environment has a high and stable temperature. Because its body temperature matches the environmental temperature, you conclude that it is an ectotherm.
You measure the metabolic rate of the reptile, and because it is higher than that of a related species that lives in temperate forests, you conclude that this reptile is an endotherm and its relative is an ectotherm.
You know that it is an ectotherm because it is not a bird or mammal.
You subject this reptile to various temperatures in the lab and find that its body temperature and metabolic rate change with the ambient temperature. You conclude that it is an ectotherm.
You subject this reptile to various temperatures in the lab and find that its body temperature and metabolic rate change with the ambient temperature. You conclude that it is an ectotherm.
Which of the following animals uses the largest percentage of its energy budget for homeostatic regulation?

a desert bird
a hydra
a desert insect
a snake in a temperate forest
a marine jelly (an invertebrate)
a desert bird
Which of the following animals is incorrectly paired with its feeding mechanism?

aphid-fluid feeder
lion-substrate feeder
baleen whale-suspension feeder
clam-suspension feeder
snake-bulk feeder
lion-substrate feeder
The mammalian trachea and esophagus both connect to the

stomach.
rectum.
pharynx.
large intestine.
epiglottis.
pharynx.
Which of the following organs is incorrectly paired with its function?

small intestine-nutrient absorption
oral cavity-starch digestion
large intestine-bile production
stomach-protein digestion
pancreas-enzyme production
large intestine-bile production
Which of the following is not a major activity of the stomach?

mechanical digestion
enzyme secretion
nutrient absorption
mucus secretion
HCl secretion
nutrient absorption
After surgical removal of an infected gallbladder, a person must be especially careful to restrict dietary intake of

protein.
fat.
sugar.
water.
starch.
fat.
If you were to jog 1 km a few hours after lunch, which stored fuel would you probably tap?

fat stored in adipose tissue
blood proteins
muscle proteins
fat stored in the liver
muscle and liver glycogen
muscle and liver glycogen
Which of the following respiratory systems is not closely associated with a blood supply?

the parapodia of a polychaete worm
the gills of a fish
the lungs of a vertebrate
the skin of an earthworm
the tracheal system of an insect
the tracheal system of an insect
Blood returning to the mammalian heart in a pulmonary vein drains first into the

vena cava.
left ventricle.
right ventricle.
right atrium.
left atrium.
left atrium.
Pulse is a direct measure of

breathing rate.
heart rate.
blood pressure.
cardiac output.
stroke volume.
heart rate.
When you hold your breath, which of the following blood gas changes first leads to the urge to breathe?

rising CO2
rising CO2 and falling O2
falling O2
rising O2
falling CO2
rising CO2
One feature that amphibians and humans have in common is

a low blood pressure in the systemic circuit.
the number of circuits for circulation.
the type of gas exchange tissues.
a complete separation of circuits for circulation.
the number of heart chambers.
the number of circuits for circulation.
If a molecule of released into the blood in your left toe is exhaled from your nose, it must pass through all of the following except

the right atrium.
an alveolus.
the pulmonary vein.
the right ventricle.
the trachea.
the pulmonary vein.
Compared with the interstitial fluid that bathes active muscle cells, blood reaching these cells in arteries has a

lower pH.
higher P(O2)
lower osmotic pressure.
greater bicarbonate concentration.
higher .P(CO2)
higher P(O2)
Which of the following reactions prevails in red blood cells traveling through alveolar capillaries? (Hb = hemoglobin)
CO2 + H2) > H2CO3
Hb + 4O2 > H2CO3
Hb + 4O2 > Hb(CO2)4
Hb(O2)4 . Hb +4O2
H2CO3 . H+ + HCO3-
Hb + 4O2 > H2CO3
Which of these is not part of insect immunity?

a protective exoskeleton
enzyme activation of microbe-killing chemicals
activation of natural killer cells
phagocytosis by hemocytes
production of antimicrobial peptides
activation of natural killer cells
An epitope associates with which part of an antigen receptor or antibody?

variable regions of a heavy chain and light chain combined
the tail
the heavy-chain constant regions only
the light-chain constant regions only
the disulfide bridge
variable regions of a heavy chain and light chain combined
Which statement best describes the difference in responses of effector B cells (plasma cells) and cytotoxic T cells?

B cells secrete antibodies against a pathogen; cytotoxic T cells kill pathogen-infected host cells.
B cells carry out the cell-mediated response; cytotoxic T cells carry out the humoral response.
B cells respond the first time a pathogen is present; cytotoxic T cells respond subsequent times.
B cells confer active immunity; cytotoxic T cells confer passive immunity.
B cells kill pathogens directly; cytotoxic T cells kill host cells.
B cells secrete antibodies against a pathogen; cytotoxic T cells kill pathogen-infected host cells.
Which of the following statements is not true?

A liver cell makes one class of MHC molecule.
An antigen can have different epitopes.
An antibody has more than one antigen-binding site.
A pathogen makes more than one antigen.
A lymphocyte has receptors for multiple different antigens.
A lymphocyte has receptors for multiple different antigens.
Which of the following should be the same in identical twins?

the set of MHC molecules produced
the set of T cell antigen receptors produced
the susceptibility to a particular virus
the set of immune cells eliminated as self-reactive
the set of antibodies produced
the set of MHC molecules produced
Vaccination increases the number of

epitopes that the immune system can recognize.
macrophages specific for a pathogen.
MHC molecules that can present an antigen.
different receptors that recognize a pathogen.
lymphocytes with receptors that can bind to the pathogen.
lymphocytes with receptors that can bind to the pathogen.
rt A
Which of the following would not help a virus avoid triggering an adaptive immune response?

producing proteins very similar to those of other viruses
having frequent mutations in genes for surface proteins
infecting and killing helper T cells
building the viral shell from host proteins
infecting cells that produce very few MHC molecules
producing proteins very similar to those of other viruses
which of the following characteristics, structures, or processes is common to both bacteria and viruses?
genetic material composed of nucleic acid
Emerging viruses arise by
all of the above (mutation of existing viruses, spread of existing viruses to new host species, spread of existing viruses more widely within their host species.
To cause a human pandemic, the H5N1 avian flu virus would have to
become capable of of human-to-human transmission
A bacterium is infected with an experimentally constructed bacteriophage composed of the T2 phage protein coat and T4 phage DNA. the new phages produced would have
T4 protein and T2 DNA
RNA viruses require their own supply of certain enzymes becasue
host cells lack enzymes that can replicate the viral genome
Fossilized stromatolites
resemble structures formed by bacterial communities that are found today in some warm, shallow, salty bays
The oxygen revolution changed Earth's environment dramatically. Which of the following took advantage of the presence of free oxygen in the oceans and atmosphere?
the evolution of cellular respiration, which used oxygen to help harvest energy from organic molecules
Which factor most likely caused animals and plants in India to differ greatly from species in nearby southeast Asia?
India was a separate continent until 45 million years ago
Adaptive radiations can be a direct consequence of four of the following five factors. select the exception:
genetic drift
Which of the following steps has not yet been accomplished by scientists studying the origin of life?
formation of photocells that use DNA to direct the polymerization of amino acids
In figure 26.4, which similarly inclusive taxon descended from the same common ancestor as Canidae?
Mustelidae
Three living species X, Y, and Z share a common ancestor T, as do extinct species U and V. A grouping that consists of species T, X, Y, and Z (but not U and V) makes up
a paraphyletic group
In a comparison of birds and mammals having four limbs is
a shared ancestral ancestor
To apply parsimony to constructing a phylogenic tree,
choose the tree that represents the fewest evolutionary changes, in either DNA sequences or morphology
Based on this tree, which statement is not correct?
Lizards are more closely related to salamanders than to humans
If you were using cladistics to build a phylogenic tree of cats, which of the following would be the best outgroup?
wolf
The relative lengths of the frog and mouse branches in the phylogeny in figure 26.12 indicate that
the homolog has evolved more slowly in mice
Plastids that are surrounded by more than two membranes are evidence of
secondary endosymbiosis
Biologists suspect that endosymbiosis gave rise to mitochondria before plastids partly because
all eukaryotes have mitochondria (or their remnants), whereas many eukaryotes so not have plastids
Which group is incorrectly paired with its description?
red algae-acquired plastids by secondary endosymbiosis
Which protists are in the same eukaryotic supergroup as land plants?
both green algae and red algae
In life cycles with an alternation of generations, multicellular haploid forms alternate with
multicellular diploid forms
Based on the phylogenic tree in figure 28.3, which of the following statements is correct?
the most basal (first to diverge) eukaryotic supergroup cannot be determined
All fungi share which of the following characteristics?
heterotrophic
Which feature seen in chytrids supports the hypothesis that they diverged earliest in fungal evolution?
flagellated spores
Which of the following cells or structures are associated with asexual reproduction in fungi?
conidiophores
The photosynthestic symbiont of a lichen is often
a green algae
Among the organisms listed here, which are thought to be the closest relatives of fungi?
animals
The adaptive advantage associated with the filamentous nature of fungal mycelia is primarily related to
an extensive surface area well suited for invasive growth and absoptive nutrition
Among the characteristics unique to animals is

sexual reproduction.
heterotrophic nutrition.
gastrulation.
flagellated sperm.
multicellularity.
gastrulation.
The distinction between sponges and other animal phyla is based mainly on the absence versus the presence of

mesoderm.
a complete digestive tract.
true tissues.
a circulatory system.
a body cavity.
true tissues.
Acoelomates are characterized by

a solid body without a cavity surrounding internal organs.
a coelom that is not completely lined with mesoderm.
the absence of a brain.
deuterostome development.
the absence of mesoderm.
a solid body without a cavity surrounding internal organs.
Which of the following was probably the least important factor in bringing about the Cambrian explosion?

the accumulation of sufficient atmospheric oxygen to support the more active metabolism of mobile animals
the origin of Hox genes and other genetic changes affecting the regulation of developmental genes
the accumulation of diverse adaptations, such as shells and different modes of locomotion
the movement of animals onto land
the emergence of predator-prey relationships among animals
the movement of animals onto land
Which of these is a point of conflict between the phylogenetic analyses presented in Figures 32.10 and 32.11 in your textbook?

the monophyly of the bilaterians
the monophyly of the animal kingdom
the relationship of taxa of segmented animals to taxa of nonsegmented animals
that sponges are basal animals
that chordates are deuterostomes
the relationship of taxa of segmented animals to taxa of nonsegmented animals
A land snail, a clam, and an octopus all share

distinct cephalization.
a mantle.
gills.
embryonic torsion.
a radula.
a mantle.
Which phylum is characterized by animals that have a segmented body?

Arthropoda
Porifera
Mollusca
Cnidaria
Platyhelminthes
Arthropoda
The water vascular system of echinoderms

is analogous to the gastrovascular cavity of flatworms.
functions in locomotion and feeding.
is bilateral in organization, even though the adult animal is not bilaterally symmetrical.
functions as a circulatory system that distributes nutrients to body cells.
moves water through the animal's body during suspension feeding.
functions in locomotion and feeding.
Which of the following combinations of phylum and description is incorrect?

Porifera-gastrovascular cavity, coelom present
Echinodermata-bilateral symmetry as a larva, coelom present
Cnidaria-radial symmetry, polyp and medusa body forms
Platyhelminthes-flatworms, gastrovascular cavity, acoelomate
Nematoda-roundworms, pseudocoelomate
Porifera-gastrovascular cavity, coelom present
In Figure 33.2 in your textbook, which two main clades branch from the most recent common ancestor of the eumetazoans?

Lophotrochozoa and Ecdysozoa
Rotifera and Deuterostomia
Deuterostomia and Bilateria
Cnidaria and Bilateria
Porifera and Cnidaria
Cnidaria and Bilateria
MAKE CONNECTIONS In Figure 33.8 in your textbook, assume that the two medusae shown at step 4 were produced by one polyp colony. Review Concept 12.1 (pp. 229-230 in your textbook) and Concept 13.4 (pp. 257-260 in your textbook), and then use your understanding of mitosis and meiosis to evaluate whether the following sentence is true or false. If false, select the answer that provides the correct reason. Although the two medusae are genetically identical, a sperm produced by one will differ genetically from an egg produced by the other.

F (the medusae are genetically identical, but so are the gametes)
F (neither the medusae or the gametes are genetically identical)
T
F (the medusae are not identical but the gametes are)
T
Select the valid comparison between eukaryotes and prokaryotes.

Eukaryotes are far more metabolically diverse than prokaryotes.
Prokaryote cells have simpler internal structure and genomic organization than eukaryotic cells.
The total biomass of eukaryotes is approximately ten times the total biomass of prokaryotes.
Prokaryote cells have simpler internal structure and genomic organization than eukaryotic cells.
Identify the thylakoid membrane of the cyanobacterium shown here.

The thylakoid membrane of the cyanobacterium is a nucleoid membrane.
The thylakoid membrane of the cyanobacterium is a chloroplast membrane.
The thylakoid membrane of the cyanobacterium is an infolded plasma membrane.
The thylakoid membrane of the cyanobacterium is an infolded plasma membrane.
Which of the following processes contributes to genetic recombination in prokaryotes?

Meiosis
Mutation
Transduction
Transduction
Approximately how many prokaryotic cells live in 5 mL of fertile soil?

About 100 million prokaryotic cells
About 10,000 prokaryotic cells
About 10 million prokaryotic cells
About 100 million prokaryotic cells
Select the correct statement about bacteria.

Certain bacteria live within rocks kilometers below the Earth's surface.
All organisms with cells containing a membrane-enclosed nucleus and organelles are eukaryotes, whereas all organisms with cells lacking a membrane-enclosed nucleus and organelles are bacteria.
The majority of bacteria cause human disease.
Certain bacteria live within rocks kilometers below the Earth's surface.
What is the function of fimbriae?

They are components of the outer cell wall in gram-negative bacteria.
They are used in motility.
They are used to transfer DNA during conjugation.
They are used to attach the cell to its substrate or to other prokaryotes.
They protect the cell from dehydration.
They are used to attach the cell to its substrate or to other prokaryotes.
How does the large amount of genetic variation observed in prokaryotes arise?

The mutation rate in prokaryotes is much higher than in eukaryotes.
They have extremely short generation times and large populations.
They can exchange DNA with many types of prokaryotes by way of horizontal gene transfer.
They have a relatively small genome.
The second and third answers are correct.
The second and third answers are correct.
( They have extremely short generation times and large populations.
They can exchange DNA with many types of prokaryotes by way of horizontal gene transfer.)
Genes for the resistance of antibiotics are usually located _____.

on the outside of the cell wall
in mitochondria
on the main chromosome
in eukaryotic cells
on plasmids
on plasmids
Bacteria that live around deep-sea, hot-water vents obtain energy by oxidizing inorganic hydrogen sulfide belched out by the vents. They use this energy to build organic molecules from carbon obtained from the carbon dioxide in seawater. These bacteria are _____.

photoheterotrophs
photoautotrophs
chemoautotrophs
chemoheterotrophs
chemoautotrophs
Which statement is true about obligate anaerobes?

They live exclusively by cellular respiration or by anaerobic respiration.
They will use O2 if it is present, but can obtain energy by fermentation if needed.
They use O2 for cellular respiration and cannot grow without it.
They are poisoned by O2.
They obtain energy by oxidizing ferrous ions.
They are poisoned by O2.
The prokaryotic organisms most likely to be found living in salt ponds are the _____.

Korarchaeota
extremophiles
thermophiles
halophiles
methanogens
halophiles
An ecological relationship between organisms of different species that are in direct contact can best be described as _____.

symbiotic
taxis
commensal
mutualistic
parasitic
symbiotic
How are archaeans most similar to bacteria?

the structure of their cell walls
nucleotide sequence of small subunit ribosomal RNA
the occurrence of introns in their chromosomes
methanogenesis
the shape of their chromosomes and plasmids
the shape of their chromosomes and plasmids
Which statement about endotoxins is true?

An example of a prokaryote that produces endotoxins is Clostridium botulinum.
Endotoxins are released only when bacteria die and their cell walls break down.
The source of endotoxins is endospores.
Endotoxins are proteins secreted by prokaryotes.
Endotoxins are components of the cell wall of gram-positive bacteria.
Endotoxins are released only when bacteria die and their cell walls break down.
Bioremediation is _____.

the use of prokaryotes in producing pharmaceutical products
the use of organisms to remove pollutants from the environment
the use of prokaryotes in producing transgenic organisms
the use of biological processes to remedy diseases
the modification of prokaryotes for industrial purposes
the use of organisms to remove pollutants from the environment
Which of the following is an example of the pattern of evolution? (Overview)

descent with modification
heredity
natural selection
the inheritance of acquired characteristics
the fossil record of the evolution of modern cetaceans
the fossil record of the evolution of modern cetaceans
What happened in the soapberry bug population in central Florida when the bugs began to feed on smaller goldenrain tree fruits?

The length of each bug's beak gradually became shorter over time.
Bugs developed short beaks, because they needed them to feed on the small fruits.
Bugs with shorter beaks had more access to food, allowing them to produce more offspring.
Bugs with shorter beaks had more access to food, allowing them to produce more offspring.
What is the meaning of Darwin's expression "descent with modification"?

Descent with modification refers to natural selection.
Descent with modification refers to evolutionary change over time.
Descent with modification refers to the partial resemblance of offspring to their parents.
Descent with modification refers to evolutionary change over time.
Soapberry bugs use needlelike "beaks" to feed on seeds within the fruits of various plants. Bugs feed most successfully when their beak length matches the size of the fruit on which they are feeding. For 25 years, populations of soapberry bugs in central Florida have been feeding on small goldenrain tree fruits that were introduced to the area, rather than on the larger native balloon vine fruits that serve as food for other soapberry bug populations. Beak lengths of soapberry bugs are variable, but the average beak length is shorter in soapberry bug populations that feed on goldenrain tree fruits than in populations that feed on balloon vine fruits, as shown in the graph. How does natural selection act on beak length in soapberry bug populations?

The action of natural selection on beak length in soapberry bug populations varies with the environment.
Natural selection increases beak length in soapberry bug populations.
Natural selection decreases beak length in soapberry bug populations.
The action of natural selection on beak length in soapberry bug populations varies with the environment.
Identify the pair of homologous structures.

Neither of the above; plants do not have homologous structures.
Maple leaf and oak leaf
Maple leaf and maple seed
Maple leaf and oak leaf
Charles Darwin _____.

was the first person to conclude that organisms evolve
proposed that unused parts of the body deteriorate
eagerly published his theory before it was well-developed
was the first to realize that fossils are remains of ancient organisms
proposed natural selection as the mechanism of evolution
proposed natural selection as the mechanism of evolution
An adaptation is _____.

an individual's attempt to conform to its environment
a trait that gives an organism a reproductive advantage in the current environment
the cause of natural selection
a trait that gives rise to a new species
all of the above
a trait that gives an organism a reproductive advantage in the current environment
From his observations of organisms in the Galapagos islands, Darwin reasoned that _____.

the shape of a bird's beak does not affect its ability to survive and reproduce
all island species should be similar to each other
organisms had adapted to new environments, giving rise to new species
the organisms in the Galapagos had been specially created to thrive in that environment
none of the above
organisms had adapted to new environments, giving rise to new species
Which of the following observations led to Darwin's major inferences?

Members of a population vary in their heritable traits.
Body parts that are not used deteriorate over time.
Organisms only go extinct when catastrophes occur.
Although organisms can produce huge numbers of offspring, many of these offspring do not survive.
The first and fourth answers are correct.
The first and fourth answers are correct. ( Members of a population vary in their heritable traits. Although organisms can produce huge numbers of offspring, many of these offspring do not survive.)
Which one of the following researchers developed a theory of evolution that was very similar to Charles Darwin's?

Cuvier
Lamarck
Wallace
Lyell
Hutton
Wallace
A group of small fish live in a lake with a uniformly light-brown sandy bottom. Most of the fish are light brown, but about 10% are mottled. This fish species is often prey for large birds that live on the shore. A construction company dumps a load of gravel in the bottom of the lake, giving it a mottled appearance. Which of these statements presents the most accurate prediction of what will happen to this fish population?

In two generations, all the fish will be mottled.
As the mottled fish are eaten, more will be produced to fill the gap.
The ratios will not change.
There is no way to predict the result.
The proportion of mottled fish will increase over time.
The proportion of mottled fish will increase over time.
Varieties of Staphylococcus aureus that are resistant to the drug methicillin _____.

developed in response to the use of methicillin
already existed in the population before methicillin was developed
always have an advantage in every environment
were strongly selected for as methicillin became widely used to treat bacterial infections
The second and fourth answers are correct.
The second and fourth answers are correct.
( already existed in the population before methicillin was developed, were strongly selected for as methicillin became widely used to treat bacterial infections)
A challenge to traditional (pre-1860) ideas about species came from embryology, when it was discovered that _____.

the embryological development of many plants and animals is almost identical
the more advanced the animal, the more slowly it develops
all animals develop similar embryonic gills
embryos of dissimilar organisms, such as sharks and humans, resemble each other
mutations have a far more dramatic effect on embryos than on adult organisms
embryos of dissimilar organisms, such as sharks and humans, resemble each other
The theory of evolution through natural selection is considered a scientific theory because _____.

it is broad enough in scope to explain many observations
it is supported by a massive body of evidence from many disciplines
it is general enough to provide many testable hypotheses
All of the above are correct.
None of the above is correct.
All of the above are correct.
What is true of microevolution?

It is evolution that involves only tiny changes to DNA, such as point mutations, producing only small (if any) changes to phenotype.
It is evolution that influences only a small subset of the populations that comprise a species.
It is evolution that is restricted to individual organisms.
It is evolution that results in the origin of small numbers of new species.
It is the kind of evolution that can change the relative abundance of a particular allele in a gene pool over the course of generations.
It is the kind of evolution that can change the relative abundance of a particular allele in a gene pool over the course of generations.
You read about soapberry bugs in Chapter 22. Select the correct statement describing relative fitness in these individuals.

A soapberry bug with high relative fitness has more mates than other bugs.
A soapberry bug with high relative fitness feeds more successfully on fruits than do other bugs.
A soapberry bug with high relative fitness has a relatively high number of offspring that survive to reproductive age.
A soapberry bug with high relative fitness has a relatively high number of offspring that survive to reproductive age.
The fruit fly Drosophila melanogaster has an allele that confers resistance to DDT and similar insecticides. Laboratory strains of D. melanogaster have been established from flies collected in the wild in the 1930s (before the widespread use of insecticides) and the 1960s (after 20 years of DDT use). Lab strains established in the 1930s have no alleles for DDT resistance. In lab strains established in the 1960s, the frequency of the DDT-resistance allele is 37%. Which statement is correct?

Alleles for DDT resistance arose by mutation during the period of DDT use because of selection for pesticide resistance.
Resistance to DDT evolved in some fruit flies in order to allow them to survive.
The evolutionary fitness associated with the heritable trait of DDT resistance changed once DDT use became widespread.
The evolutionary fitness associated with the heritable trait of DDT resistance changed once DDT use became widespread.
One out of 10,000 babies born in North America is affected by cystic fibrosis, a recessive condition. Assuming that the North American human population is in Hardy-Weinberg equilibrium for this trait, what percentage of the population is heterozygous for this trait? (Remember the equation for a population in Hardy-Weinberg equilibrium: p2 + 2pq + q2 = 1.)

0.01%
0.0001%
2%
2%
Allele frequencies in a gene pool may shift randomly and by chance. What is this random shift called?

directional selection
gene flow
genetic drift
genetic drift
Which statement correctly describes the role of chance in evolution?

The ultimate source of new alleles is mutation, random changes in the nucleotide sequences of an organism's DNA.
An allele that increases evolutionary fitness cannot be lost from a population by chance events.
Evolutionary change proceeds by an accumulation of changes that occur by chance.
The ultimate source of new alleles is mutation, random changes in the nucleotide sequences of an organism's DNA.
Rabbit ear size tends to decrease as latitude increases. This is an example of _____.

genetic drift
a cline
polymorphism
heterozygote advantage
artificial selection
a cline
The original source of all genetic variation is _____.

sexual reproduction
recombination
natural selection
independent assortment
mutation
mutation
According to the Hardy-Weinberg theorem, the frequencies of alleles in a population will remain constant if _____ is the only process that affects the gene pool.

mutation
sexual reproduction
immigration
sexual selection
genetic drift
sexual reproduction
The evolutionary effects of genetic drift are greatest when _____.

the population size is large
the population size is small
sexual selection occurs
intraspecific competition is intense
intraspecific competition is weak
the population size is small
What situation most likely explains the occasional high frequency of certain inherited disorders among human populations established by a small population?

mutation
nucleotide variability
bottleneck effect
gene flow
founder effect
founder effect
In evolutionary terms, an organism's fitness is measured by its _____.

genetic variability
health
mutation rate
stability in the face of environmental change
contribution to the gene pool of the next generation
contribution to the gene pool of the next generation
Blue poppies native to China were grown at a plant-breeding center in California. The plants with the thickest leaves were most likely to survive and reproduce in the drier climate. After several generations, the percentage of thick-leaved plants had increased by 42%. This adaptation of the poppies to their new environment is due to _____.

stabilizing selection
disruptive selection
neutral variation
directional selection
genetic drift
directional selection
What is the only evolutionary mechanism that consistently leads to adaptive evolution?

natural selection
the bottleneck effect
gene flow
genetic drift
neutral variation
natural selection
How does diploidy help to preserve genetic variation?

It fosters the exchange of genes between different populations.
It helps individual organisms make a greater contribution to the gene pool of the next generation.
It allows the frequency of a recessive allele in a population to be predicted under certain conditions.
It allows recessive alleles that may not be favored in the current environment to be preserved in the gene pool by propagation in heterozygotes.
It restricts the gene pool by chance events such as floods or other catastrophic events.
It allows recessive alleles that may not be favored in the current environment to be preserved in the gene pool by propagation in heterozygotes.
Adaptive radiations on archipelagos (island chains) represent some of the best-understood speciation events. Why is an ancestral species more likely to give rise to multiple descendent species on an archipelago than on an equal-sized area of mainland?

Populations on nearby islands are more likely to be genetically isolated than populations that are equally close to one another on the mainland.
By chance, different species will colonize different islands in a chain.
Favorable mutations are more likely to arise on an archipelago as populations try to adapt to conditions on their specific island.
Populations on nearby islands are more likely to be genetically isolated than populations that are equally close to one another on the mainland.
The original habitat of the North American maggot fly, Rhagoletis pomonella, was native hawthorn trees. About 200 years ago, some populations colonized newly introduced apple trees. The two populations are still classified as subspecies, but sympatric speciation is under way. What has contributed to incipient speciation in the maggot fly?

Maggot flies that feed and lay eggs on apples have gradually become adapted to this fruit.
Because apples mature more quickly than hawthorn fruit, the apple-feeding flies have been selected for more rapid development.
Apple maggot flies try to avoid mating with hawthorn maggot flies.
Because apples mature more quickly than hawthorn fruit, the apple-feeding flies have been selected for more rapid development.
How long does it take new species to form on Earth?

millions of years
The time required varies considerably.
Speciation no longer takes place on Earth.
The time required varies considerably.
In Europe, there is a long narrow hybrid zone, shown in red on the map, between the high-altitude habitat of the yellow-bellied toad and the lowland habitat of the fire-bellied toad. Despite this, there is little gene flow between the two species. Select the correct explanation.

Hybrids have poor survival and reproduction and thus produce few viable offspring with members of either parent species.
Yellow-bellied toads and fire-bellied toads are two different species.
Toads mate only with their own kind in order to avoid producing unhealthy hybrid young.
Hybrids have poor survival and reproduction and thus produce few viable offspring with members of either parent species.
Select the correct statement describing sympatric speciation.

Sympatric speciation has never been observed in nature.
Sympatric speciation is always initiated by geographic isolation of two populations.
Sympatric speciation can occur in a single generation.
Sympatric speciation can occur in a single generation.
Two animals are considered members of different species if they _____.

are members of different populations
live in different habitats
are geographically isolated
look different
cannot mate and produce viable, fertile offspring
cannot mate and produce viable, fertile offspring
According to the phylogenetic species concept, what is a species?

a clone of genetically identical organisms
a population that interbreeds and produces fertile offspring
a set of organisms with a unique genetic history
a population that is physically able to mate even if there are no offspring or the offspring are infertile
a population with a distinct fossil record
a set of organisms with a unique genetic history
What is the most important factor that holds a gene pool together and prevents speciation?

hybridization
prezygotic barriers
gene flow
sexual selection
behavioral isolation
gene flow
Which of these is an example of temporal isolation?

One species performs a specific courtship dance. the other species does not.
The average weight of the individuals in one species is 45 kg; in the other species the average is 290 kg.
One species is nocturnal, and the other species is not.
One is a type of primate, the other is a type of marsupial.
One species is found only in New York, the other only in London.
One species is nocturnal, and the other species is not.
Which of the following is the first step in allopatric speciation?

genetic drift
formation of a reproductive barrier
geographic isolation
polyploidy
hybridization
geographic isolation
Sympatric speciation is _____.

the process by which most animal species have evolved
the appearance of a new species in the same area as the parent population
initiated by the appearance of a geographic barrier
especially important in the evolution of island species
the emergence of many species from a single ancestor
the appearance of a new species in the same area as the parent population
Hybrid zones provide an opportunity to investigate _____.

the evolution of reproductive isolation
punctuated equilibrium
polyploidy
allopatric speciation
mutations
the evolution of reproductive isolation
A certain species of salamander was split into two populations by a wide, dry valley, and the populations began to diverge from each other. After a period of time, some members of the two populations began to interbreed in a hybrid zone at the southern end of the valley. Only weak reproductive barriers existed by this time, so the two populations could freely interbreed and re-establish gene flow. This outcome in a hybrid zone is known as _____.

reinforcement
stability
speciation
punctuated equilibrium
fusion
fusion
According to the _____ model, evolution occurs in spurts; species evolve relatively rapidly then remain unchanged for long periods.

geographic isolation
nondisjunction
adaptive radiation
gradualist
punctuated equilibrium
punctuated equilibrium
Which of the following has been shown to cause speciation most rapidly?

autopolyploidy
sexual selection
hybridization
differential resource exploitation
punctuated equilibrium
autopolyploidy
In 1959, doctors began using the powerful antibiotic methicillin to treat infections of Staphylococcus aureus, but within two years, methicillin-resistant strains of S. aureus (MRSA) appeared. How did the resistant strains of S. aureus emerge?

Staphylococcus aureus bacteria that were able to synthesize cell walls using a protein that was not affected by methicillin survived the methicillin treatments and reproduced at higher rates than did other individuals. Over time, these resistant individuals became increasingly common.
In response to treatment of Staphylococcus aureus infections with methicillin, bacterial populations gradually began to synthesize cell walls using a protein that was not affected by methicillin.
In response to treatment of Staphylococcus aureus infections with methicillin, some bacteria began to synthesize cell walls using a protein that was not affected by methicillin. These bacteria survived the methicillin treatments and reproduced at higher rates than did other individuals. Over time, these resistant individuals became increasingly common.
Staphylococcus aureus bacteria that were able to synthesize cell walls using a protein that was not affected by methicillin survived the methicillin treatments and reproduced at higher rates than did other individuals. Over time, these resistant individuals became increasingly common.
Darwin's thinking while on the Beagle was greatly influenced by his reading of a book written by _____.

Chaucer
Shakespeare
Bishop Ussher
Wallace
Lyell
Lyell
According to this climatograph, London experiences more precipitation during _____ than during any other month.

July
January
June
February
October
October
Which of these is a consequence of uniformitarianism?

Earth is round, not flat.
Populations evolve.
Earth is very old.
Populations reproduce faster than their food supply.
A Creator made Earth.
Earth is very old.
The Argentinean pampas are a type of _____.

temperate deciduous forest
desert
grassland
chaparral
tropical forest
grassland
At the fossil site at Punta Alta, Darwin found evidence _____.

that Brazilian flatworms were a type of slug
of extinction
of divine creation
that the pampas could support large mammals
that extinction does not happen
of extinction
Patagonia is a _____.

tropical forest
savanna
grassland
chaparral
desert
desert
His experiences with Fuegians and slavery convinced Darwin that differences among all peoples are primarily _____ differences.

cultural
cultural and genetic
genetic
due to height
genetic and height-related
cultural
Species in hot climates tend to _____ compared to species in cold climates.

have less fear of humans
have smaller surface-to-volume ratios
experience less interspecific competition
have larger surface-to-volume ratios
be less colorful
have larger surface-to-volume ratios
In the Andes, at elevations of 12,000 feet, Darwin collected fossilized marine shells. The existence of marine shells at this altitude provided evidence that _____.

the deposit had been gradually uplifted to its present location
geologic processes occur at a rapid rate
marine organisms can survive at great elevation
someone carried them from the oceans and left them on the mountains
Earth's surface does not change
the deposit had been gradually uplifted to its present location
The Galápagos Islands are located _____.

in the Arctic
off the coast of California
off the coast of Brazil
Off the coast of Ecuador
in the Antarctic
Off the coast of Ecuador
Why were the Galápagos Islands so important to Darwin's formulation of natural selection?

They are where Darwin did most of his writing.
The species found on the Galápagos Islands are also found in Australia.
The Galápagos Islands are the only place in the world where finches are found.
They provided evidence in support of uniformitarianism.
Each island in the Galápagos possessed unique species.
Each island in the Galápagos possessed unique species.
The Galápagos Islands are cooled by the _____.

Kuroshio Current
Equatorial Countercurrent
Monsoon Drift
Gulf Stream
Humboldt Current
Humboldt Current
How many finch species did Darwin send to the British Museum?

17
30
13
15
21
13
Which of the following statements about natural selection is true?

Natural selection occurs in opposition to evolution.
Natural selection favors individuals that reproduce more than others.
Natural selection is a process whereby genes are selected randomly for preservation in the next generation.
Natural selection can be used by farmers to generate organisms with desirable traits.
Natural selection favors individuals that reproduce more than others.
Which term describes a trait that increases an individual's ability to survive in a particular environment?

Adaptation
Heritability
Fitness
Evolution
Adaptation
Which term describes the ability of a trait to be passed on to offspring?

Evolution
Adaptation
Heritability
Fitness
Heritability
Which of the following organisms could be produced by artificial selection?

A rabbit that is housebroken.
A chimpanzee that communicates through sign language.
A cow that produces a large quantity of milk.
A dog that serves as the "eyes" for a blind individual.
A cow that produces a large quantity of milk.
Which pair of chickens should a farmer breed to produce larger chickens?

Small hen, small rooster
Large hen, small rooster
Large hen, large rooster
Small hen, large rooster
Large hen, large rooster
A farmer wishes to develop a strain of high-yield corn that is also resistant to drought. He has the following individuals from the current year's crop:

Individual A—Yield: 179 bushels/acre; drought resistance: high
Individual B—Yield: 220 bushels/acre; drought resistance: low
Individual C—Yield: 185 bushels/acre; drought resistance: medium
Individual D—Yield: 140 bushels/acre; drought resistance: high
Individual E—Yield: 200 bushels/acre; drought resistance: medium

Which of the following crosses would produce the highest corn yield with the highest resistance to drought?

A and E
B and B
C and E
A and B
A and E
A challenge to traditional (pre-1860) ideas about species came from embryology, when it was discovered that _____.

mutations have a far more dramatic effect on embryos than on adult organisms
all animals develop similar embryonic gills
the embryological development of many plants and animals is almost identical
the more advanced the animal, the more slowly it develops
embryos of dissimilar organisms, such as sharks and humans, resemble each other
embryos of dissimilar organisms, such as sharks and humans, resemble each other
The wing of a bat is homologous to the _____ of a whale.

baleen
tail
flipper
rib cage
blowhole
flipper
Which of these lists contains the four postulates of natural selection?

Uniform population, heritable traits, selection, differential survival or reproduction
Variation in population, heritable variation, selection, differential survival or reproduction
Variation in population, heritable variation, selection, unlimited survival and reproduction
Variation in population, environmental variation, selection, differential survival or reproduction
Variation in population, heritable variation, selection, differential survival or reproduction
Which of the following statements is an accurate combination of postulates 1 and 2 of natural selection?

Heritable variation exists for traits among individuals in a population.
Drug resistance exists among all individuals in a population.
Environmental variation exists for traits among individuals in a population.
Heritable variation does not exist among individuals in a population.
Heritable variation exists for traits among individuals in a population.
Which of the following statements is an accurate combination of postulates 3 and 4 of natural selection?

Individuals experience uniform success in their ability to survive or reproduce.
Individuals experience no success in their ability to survive or reproduce.
Individuals experience unlimited success in their ability to survive or reproduce.
Individuals experience differential success in their ability to survive or reproduce.
Individuals experience differential success in their ability to survive or reproduce
Does the ability of a Mycobacterium tuberculosis cell to infect a new host depend on its drug-resistant phenotype?

Yes, drug-susceptible cells can infect a new host more easily than drug-resistant cells.
Yes, drug-resistant cells can infect a new host more easily than drug-susceptible cells.
No, drug-susceptible cells and drug-resistant cells are equally likely to infect a new host.
No, drug-susceptible cells and drug-resistant cells are equally likely to infect a new host.
Which of the following statements describes the evolution by natural selection of Mycobacterium tuberculosis bacteria in their new environment?

The drug-susceptiblity trait is an adaptation to the environment in which human hosts are medicated with the antibiotic rifampin.
The drug-resistance trait is an adaptation to the environment in which human hosts travel worldwide and are exposed to new strains of bacteria.
The drug-susceptiblity trait is an adaptation to the environment of antibacterial soaps.
The drug-resistance trait is an adaptation to the environment in which human hosts are medicated with the antibiotic rifampin.
The drug-resistance trait is an adaptation to the environment in which human hosts are medicated with the antibiotic rifampin.
In the United States today, about half of the corn crop is genetically engineered with a protein that is toxic to corn borers, an insect pest of corn. Which of the following conditions would be necessary for evolution of resistance to the toxic protein to occur in the corn borer?

The corn borer must lack variation in resistance to the toxic protein.
The corn borer must have or generate (by mutation) heritable variation in resistance to the toxic protein. The resistant corn borers must survive better or reproduce more than nonresistant corn borers.
The corn borers must experience no success in their ability to survive or reproduce.
The corn borers must experience unlimited success in their ability to survive or reproduce.
The corn borer must have or generate (by mutation) heritable variation in resistance to the toxic protein. The resistant corn borers must survive better or reproduce more than nonresistant corn borers.
True or false? It would be difficult to assess whether the drug-susceptible or drug-resistant phenotype in a population of Mycobacterium tuberculosis was more fit in an environment without antibiotics.

True
False
True
What is unique about deer mice?

They are the most populous mouse found in North America.
They are the only mice that hibernate.
They are the only mice that reproduce three times per year.
They are the only mice found in one distinct color.
They are the most populous mouse found in North America.
For this project, which of the following are scientists studying?

lab and wild mice
lab mice
genetically-engineered mice
wild mice
wild mice
You wish to research how genetics determine color of deer mice. How many genes should you focus on?

1
3
5
7
1
The three-spine stickleback typically lacks armor in fresh water. Why?

Due to delayed development.
To allow for faster growth.
It doesn't need the protection.
The armor hinders its hunting.
To allow for faster growth.
Which of the following is true?

Genotype determines phenotype.
Genotype and phenotype are the same thing.
Phenotype determines genotype.
Genotype and phenotype are not related.
Genotype determines phenotype.
Within six months of effectively using methicillin to treat S. aureus infections in a community, all new infections were caused by MRSA. How can this result best be explained?

The drug caused the S. aureus DNA to change.
In response to the drug, S. aureus began making drug-resistant versions of the protein targeted by the drug.
A patient must have become infected with MRSA from another community.
S. aureus can resist vaccines.
Some drug-resistant bacteria were present at the start of treatment, and natural selection increased their frequency.
Some drug-resistant bacteria were present at the start of treatment, and natural selection increased their frequency.
The upper forelimbs of humans and bats have fairly similar skeletal structures, whereas the corresponding bones in whales have very different shapes and proportions. However, genetic data suggest that all three kinds of organisms diverged from a common ancestor at about the same time. Which of the following is the most likely explanation for these data?

Humans and bats evolved by natural selection, and whales evolved by Lamarckian mechanisms.
Forelimb evolution was adaptive in people and bats, but not in whales.
Natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy.
Genes mutate faster in whales than in humans or bats.
Whales are not properly classified as mammals.
Natural selection in an aquatic environment resulted in significant changes to whale forelimb anatomy.
DNA sequences in many human genes are very similar to the sequences of corresponding genes in chimpanzees. The most likely explanation for this result is that

convergent evolution led to the DNA similarities.
humans evolved from chimpanzees.
chimpanzees evolved from humans.
humans and chimpanzees are not closely related.
humans and chimpanzees share a relatively recent common ancestor.
humans and chimpanzees share a relatively recent common ancestor.
Which of the following is not an observation or inference on which natural selection is based?

There is heritable variation among individuals.
Poorly adapted individuals never produce offspring.
Individuals whose characteristics are best suited to the environment generally leave more offspring than those whose characteristics are less well suited.
Species produce more offspring than the environment can support.
Only a fraction of an individual's offspring may survive.
Poorly adapted individuals never produce offspring.
Which of the following observations helped Darwin shape his concept of descent with modification?

South American temperate plants are more similar to the tropical plants of South America than to the temperate plants of Europe.
Species diversity declines farther from the equator.
Fewer species live on islands than on the nearest continents.
Earthquakes reshape life by causing mass extinctions.
Birds can be found on islands located farther from the mainland than the birds' maximum nonstop flight distance.
South American temperate plants are more similar to the tropical plants of South America than to the temperate plants of Europe.
Which of the following is an example of the pattern of evolution? (Overview)

the inheritance of acquired characteristics
descent with modification
natural selection
the fossil record of the evolution of modern cetaceans
heredity
the fossil record of the evolution of modern cetaceans
What is the meaning of Darwin's expression "descent with modification"?

Descent with modification refers to the partial resemblance of offspring to their parents.
Descent with modification refers to evolutionary change over time.
Descent with modification refers to natural selection.
Descent with modification refers to evolutionary change over time.
Where are the Solomon Islands located?

in the Mediterranean Sea
in the South Pacific
off the coast of California
off the southern tip of Florida
in the South Pacific
Scientists studying evolution on the Solomon Islands described which animal as the 'poster child' for the biological species concept?

frog
white-eye bird
sea turtle
snake
white-eye bird
Based on the video, what can you infer about speciation--the process by which one species splits into two or more species?

New species typically form as a consequence of new parasites or predators in the environment.
It is rare for new species to form on islands.
Different species are typically very different in appearance, even if they are closely related.
Physical separation of populations is often part of the speciation process.
Physical separation of populations is often part of the speciation process.
Why did the biologists consider a frog that they found to be a new species?

Its coloration was different from other known frogs.
It jumped higher than other known frogs.
It was larger than any known frog.
Its call was unique.
Its call was unique.
When Darwin wrote On the Origin of Species, he knew very little about the subject of _____, an essential component of evolutionary theory today.

botany
marine biology
zoology
genetics
genetics
Where are the Galapagos Islands located?

600 miles west of Ecuador, near the equator
in the Mediterranean Sea, as part of the Greek Islands
northeast of Australia along the Great Barrier Reef
near the tip of South Africa
600 miles west of Ecuador, near the equator
Which of the following sets of animals are likely to be found on the Galapagos Islands?

ostriches, cougars, porcupines
frogs, lungfish, mountain goats
beaver, snakes, armadillos
tortoises, finches, blue-footed boobies
tortoises, finches, blue-footed boobies
Which species is threatening the natural wildlife on the Galapagos Islands?

Asian carp
mountain lions
zebra mussels
humans
humans
he Galapagos Islands were the first place on Earth to _____.

be declared a world heritage site
be invaded by human-introduced species
suffer the complete extinction of all native species
be declared off-limits to all humans
be declared a world heritage site
Tourism on the Galapagos Islands is being restricted by requiring tourists to _____.

view the islands only from the water
visit each island in groups of only ten individuals at a time
be escorted by trained guides at all times
stay at least 100 feet away from all animals on the islands
be escorted by trained guides at all times