MasteringBiology for ECOLOGY unit

On a global scale, energy _____ ecosystems whereas chemical elements _____ ecosystems.

flows through, are recycled in

Consider this segment of a food web: Snails and grasshoppers eat pepper plants; spiders eat grasshoppers; shrews eat snails and spiders; owls eat shrews. The shrew occupies the trophic level(s) of _____.

secondary and tertiary consumers

The producers in aquatic ecosystems include organisms in which of the following groups?
a. cyanobacteria
b. algae
c. plants
d. autotrophs
e. all of the above

e

The relationship between biomass and primary productivity is that _____.

primary productivity is the rate at which biomass is produced

_____ are secondary consumers.
a. producers
b. herbivores
c. plants
d. cows
e. carnivores

e

Approximately _____% of the energy at one trophic level is passed on to the next highest trophic level.

5-10%

10,000 kcal of producer could support approximately _____ kcal of tertiary consumer.

10

Which of these provides your body with energy?
a. minerals
b. fats
c. vitamins
d. oxygen
e. light

b

Plants use _____ as a source of energy.

light

What element is found in all organic compounds?

carbon

Plants obtain carbon from _____.

carbon dioxide

Where do plants get the energy to make organic molecules?

light

Which of these is NOT an organic molecule?
a. carbohydrates
b. minerals
c. fats
d. proteins
e. glucose

b

Where do plants get the carbon they use to make organic molecules?

carbon dioxide

Nitrifying bacteria convert _____ to _____.

ammonium to nitrates

_____ removes nitrogen from the atmosphere.

nitrogen fixation

Denitrifying bacteria convert _____ to _____.

nitrates to nitrogen gas

Which of the activities listed below could help limit global warming by slowing the increase in atmospheric carbon dioxide levels?
a. burning vegetation to clear land for agriculture
b. using more electrical appliances and cars
c. limiting soil erosion so organic matter takes longer to decompose
d. cutting down forests to build houses
e. replacing fossil fuels with nuclear energy
f. choosing a fuel-efficient car, or bicycling to school or work

c, e, f

An ecosystem is unlikely to be limited by the supply of _____ because it is obtained from the air.

carbon

In contrast to bioremediation, which is a strategy for _____, biological augmentation _____ a degraded ecosystem.

removing harmful substances…uses organisms to add essential materials to

The energy for nearly every organism in nearly every ecosystem ultimately comes from _____.

the sun

Which of the following equations is correct?
a. NPP = GPP − R
b. R = NPP + GPP
c. GPP = NPP − R
d. NPP = GPP + R
e. NPP = GPP/R

a

Why is a diagram of energy flow from trophic level to trophic level shaped like a pyramid?

Most energy at each level is lost, leaving little for the next.

Which animal product is least efficient at converting feed consumed into the final product?
a. eggs
b. milk
c. beef
d. pork
e. chicken

c

Roughly how many kilograms of pork do you expect to get for every 100 kilograms of feed consumed?

20 kg

Assume you are raising beef and that feed is costing you $1.00 per kilogram. Roughly how much money are you spending on feed for each kilogram of beef produced?

$12.00

Surprisingly, milk has a conversion efficiency greater than 100%. What is the best explanation for this?

Most of milk’s mass comes from water consumption, not feed consumption.

For a country with abundant land and water resources but limited financial resources, which animal product would most likely be favored by agricultural policy?
a. eggs
b. milk
c. beef
d. pork
e. chicken

b

For a country where chicken raising and eating is socially unacceptable and water resources are scarce, which animal product would most likely be favored by agricultural policy?
a. pork
b. milk
c. eggs
d. beef

a

Despite its high resource usage, beef is a major commodity due to the high value per kilogram of the final product. Which of the following changes would cause a reduction in beef production?
a. a dramatic rise in the cost of feed, land, and water to the beef producer
b. an agricultural program that subsidized pork production so that the profit per kilogram of pork was comparable to that for beef
c. a precipitous fall in the price per kilogram of beef
d. all of the above
e. none of the above

d

Which of the following statements about the movement of nutrients through an ecosystem is true?
a. Carbon cycles between the atmosphere and living biomass.
b. Nutrients in the soil can be eaten and used directly by animals.
c. An organism transfers only its energy to the organism that eats it.
d. A biogeochemical cycle is the path that an element takes as it moves from organism to organism.

a

True or false? Local biogeochemical cycles are isolated within their particular ecosystem and all ions and molecules remain in that ecosystem permanently.

false

Which area is not one of the three major reservoirs of the global carbon cycle?
a. Oceans.
b. Terrestrial ecosystems.
c. Sedimentary rock.
d. Atmosphere.

c

True or false? In the global carbon cycle, rivers link the terrestrial and marine reservoirs of carbon, whereas carbon exchange between the atmosphere and the ocean is achieved by active transport.

false

How does carbon move from the biota to the atmosphere?

carbon dioxide is released during cellular respiration

How have humans altered the global carbon cycle?

carbon inputs into the atmosphere have risen

How do greenhouse gases contribute to global warming?

they prevent infrared light from leaving Earth’s atmosphere

What name is given to the process by which detritivores return carbon to the atmosphere?

decomposition

Which of these removes carbon from the atmosphere?
a. logging trees
b. rabbits
c. burning fossil fuels, such as oil
d. bobcats
e. algae

e

Detritus is composed of _____.

dead organic matter and excreted wastes

Biogeochemical cycles are crucial to ecosystem function because _____.

nutrients and other life-sustaining molecules are in limited supply and must be continually recycled

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

c

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 fix N2

Your textbook states, "Like organisms, ecosystems are open systems." Which of the following provide a legitimate example to illustrate this statement?
a. Earth’s atmosphere is bombarded by about 1022 joules of solar radiation each day.
b. Detritivores in soil consume nonliving organic matter and make the nutrients available to plants.
c. 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.

a and c

How do pyramids of net production and pyramids of biomass differ?

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

Bees can see colors we cannot see, and they can detect minute amounts of chemicals we cannot sense. Unlike many insects, bees cannot hear very well. A biologist would probably give which of the following as the ultimate explanation for their poor hearing?
a) If a bee could hear, its highly programmed brain would be overwhelmed with information.
b) If bees could hear, the noise of the hive would be overstimulating.
c) Bees are too small to have functional ears.
d) This is an example of altruism.
e) Hearing may not contribute much to a bee’s reproductive success.

e

Animal communication involves what type of sensory input?
a) tactile
b) visual
c) olfactory
d) auditory
e) All of the above are correct.

e

A learning process that can occur only during a limited period of the individual’s development is called _____.

imprinting

Every morning a graduate student turns on the light in the laboratory and then feeds the fish in the aquarium. After a couple of weeks of this routine, the graduate student notices that the fish come to the surface to feed as soon as the lights are turned on. The behavior of the fish is a result of _____.
a) classical conditioning
b) cognition
c) positive phototaxis
d) imprinting
e) instinct

a

An unlearned behavior directly linked to a stimulus that is carried to completion once initiated and is essentially unchangeable is _____.

fixed action pattern

Feeding behavior with a high intake to expenditure ratio is called _____.
a) heterotrophism
b) scavenging
c) herbivory
d) optimal foraging
e) agonistic behavior

d

Imagine that you are studying the food preferences of a lizard species across its range. You have hypothesized that because these populations are fairly separate from one another, the lizards have evolved different food preferences. You discover that in the desert, the lizard seems to prefer various types of flies, whereas at higher, wetter altitudes, it prefers one type of beetle. Does this observation support your hypothesis?
a) No. First, I must determine if both groups can be trained to eat the same type of food.
b) No. First I need to determine whether the offspring of these lizards, raised in the laboratory under the same conditions, will reflect the parental food preferences.
c) No. This cannot be determined without first sequencing and comparing the lizards’ DNA.
d) Yes. Not only do the lizards prefer different foods, but there is also evidence that the foods they prefer are not necessarily the most abundant.
e) Yes. The lizards obviously prefer different foods.

b

Which alternative hypothesis is made far less likely by having three R and K lines, rather than one of each?
a) The difference between the R and K lines arose through a random process such as genetic drift.
b) The difference between the R and K lines arose through gene flow.
c) The difference between the R and K lines is the result of different for allele frequencies between the population groups.
d) The difference between the R and K lines is the result of environmental differences in the food availability of their habitats.

a

An individual organism has the option to raise various offspring and/or genetic relatives. Which of the following options represents the greatest genetic success?
a) one full sibling, one grandchild, and two first cousins
b) one offspring, one nephew, and two grandchildren
c) two offspring
d) eight first cousins
e) one offspring and two nieces

b

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

e

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?
a) polygyny
b) polyandry
c) promiscuity
d) certainty of paternity
e) monogamy

b

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…
a) renewal of mating and nest-building behaviors.
b) addition of new syllables to a canary’s song repertoire.
c) crystallization of subsong into adult songs.
d) sensitive period in which canary parents imprint on new offspring.
e) elimination of the memorized template for songs sung the previous year.

b

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…
a) the behavioral difference is caused by genetic differences between populations.
b) members of different populations differ in learning ability.
c) the cultural tradition of using stones to crack nuts has arisen in only some populations.
d) members of different populations have different nutritional requirements.
e) members of different populations differ in manual dexterity.

c

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

a

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?
a) This behavior is genetic.
b) This behavior is likely to increase gosling survival.
c) This behavior is not adaptive because goslings may imprint on objects other than their parents.

b

A female zebra finch reared by a father with a red feather taped to his head will select a mate with a similar ornament over an unornamented male. What are plausible ultimate explanations for this behavior (i.e., why it occurs in the context of natural selection)?
a) A female zebra finch that chooses a mate that resembles her father is more likely to reproduce successfully.
b) A female zebra finch learns to recognize suitable mates by observing her father.
c) Zebra finches are able to perceive ornamentation on other birds.

a

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

c

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?
a) Coastal snakes that readily eat banana slugs gain most of their calories from this prey species.
b) Coastal snakes have a genetically acquired taste for banana slugs.
c) Coastal snakes can detect odor molecules produced by banana slugs.

b & c

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?
a) Cross-fostering studies provide information about the evolutionary relationship between the two species.
b) Cross-fostering studies provide information about the relative importance of nature and nurture in the development of a trait.
c) Changes in the behavior of cross-fostered young provide information about how the social and physical environment influences behavior.

b & c

Behaviors are diverse and important for survival and reproduction. Some behaviors are learned, such as the species-specific song of a yellow warbler which is different from the song of a blue-winged warbler. Other behaviors are innate, such as a female cat in heat urinating more often and in many places to attract a mate or honeybees do a "dance" that indicates the distance and direction of a food source when they return to their hive. Which of the following statements supports the idea that behaviors are important in survival and therefore affect natural selection?
a) Learned behaviors may not necessarily increase fitness. Baby warblers can learn the song of another species.
b) All behaviors are survival mechanisms that increase reproductive fitness by increasing mutation rates.
c) Both innate and learned behaviors are entirely based on genes inherited from parents.
d) Innate behaviors are the result of selection for individual survival and reproductive success.

d

A male stickleback fish will attack other male sticklebacks that invade its nesting territory. It will only attack male fish, which display the red belly characteristic of the species. Why has natural selection favored this behavior?
a) The behavior reduces interspecific competition, which gives the male stickleback access to more food.
b) The behavior allows the male to establish a defined space for breeding with female sticklebacks.
c) The behavior allows the male stickleback to attract females with its aggressive display.
d) The behavior is a mechanism to reduce predation and resource competition.

c

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

a

Which of the following causes Earth’s seasons?
a) ocean currents
b) Earth’s tilt on its axis
c) vertical air circulation
d) global wind patterns
e) changes in the Earth’s distance from the sun

b

Of the following, which is the most inclusive level of organization in nature?
a) biosphere
b) cell
c) community
d) population
e) ecosystem

a

Which of the following investigations is an example of the study of an abiotic factor?
a) investigating how the amount of annual precipitation affects the distribution of a tree species
b) observing interactions among various organisms in a rainforest canopy
c) the relationship between finch beak size and food availability on two different Galapagos Islands
d) identifying food sources for an egret population
e) investigating how an elk population competes for food

a

In most cases, the two major climatic factors affecting the distribution of organisms in terrestrial ecosystems are _____.

water and temperature

Which of the biomes—tundra, coniferous forest, temperate broadleaf forest, temperate grassland, savanna, chaparral, desert, tropical rainforest—require periodic fires to maintain their existence?
a) tropical forest, savanna, chaparral, temperate grassland, and coniferous forest
b) savanna and chaparral
c) savanna, desert, chaparral, temperate grassland, and temperate broadleaf forest
d) savanna, chaparral, temperate grassland, tundra, and coniferous forest
e) savanna, chaparral, temperate grassland, and coniferous forest

e

In which biome would you most likely find plants that exhibit C4 or CAM photosynthesis?
a) coniferous forest
b) desert
c) tundra
d) tropical forest
e) temperate grassland

b

Some arctic tundra ecosystems receive as little precipitation as deserts but have much more dense vegetation. What climatic factor might explain this difference?
a) Tundra is much warmer than deserts, so less water evaporates during the growing season and the tundra stays more moist.
b) Tundra is much cooler than deserts, so less water evaporates during the growing season and the tundra stays more moist.
c) In addition to rain, tundra also receives water in the form of snow.
d) Tundra plants are better adapted to dry conditions than desert plants.

b

Which of these is characteristic of the photic zone of a freshwater biome?
a) the presence of algae
b) relatively cool water
c) relatively stable water temperature
d) dead organic matter
e) low oxygen level

a

The benthic zone of aquatic environments is defined as the _____.
a) region that receives abundant sunlight
b) region where phytoplankton are found
c) region that receives little or no light
d) substrate at the bottom of the body of water
e) region that is flooded at high tide and not covered by water at low tide

d

The _____ biome is the largest of Earth’s biomes.

marine

A(n) _____ is a region where fresh water and salt water mix.

estuary

Aquatic biomes can be distinguished by chemical characteristics such as dissolved oxygen content and salinity and by physical characteristics such as water flow. Which five of the following statements about aquatic biomes are true?
a) Estuaries are very productive and are used as breeding grounds by many species of fish.
b) Temperature drives water movement in some lakes.
c) Tropical coral reefs generally exist in relatively shallow areas of the ocean.
d) All wetlands have soils that dry out periodically.
e) A freshwater organism permanently attached to the substrate would be unlikely to survive and reproduce in an estuary.
f) Wetlands have slow water movement or no water movement and no turnover.
g) The lowest levels of dissolved oxygen in a stream are generally found in its turbulent headwaters.

a, b, c, e, f

Which of the following examples demonstrate an ecological effect leading to an evolutionary effect?
a) Fish that swim the fastest in running water catch the most prey and more easily escape predation.
b) The insects that spend the most time exposed to sunlight have the most mutations from UV light, and thus evolve the fastest
c) When seeds are not plentiful, trees produce more seeds.
d) A few individuals with denser fur survive the coldest years of an ice age, and the offspring of the reproducing survivors of the ice age will likely have more dense fur.

d

Which would be a consequence of the removal of predators from a population such as the Trinidadian guppy population?
a) Guppies would produce fewer but larger offspring.
b) The nitrogen excretion rate would increase.
c) Guppy color patterns would change; guppies would produce fewer but larger offspring; the nitrogen excretion rate would increase and the rate of growth of primary producers such as algae would increase.
d) Guppy color patterns would change.
e) Primary producers such as algae would overgrow.

c

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) Disturbances can create patches of different habitats in a community.
b) A healthy community is in an equilibrium state of balance, with few disturbances.
c) The effects of disturbance on a community are almost always negative.

a

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

b

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

a

To determine the density of a rabbit population, you would need to know the number of rabbits and _____.

the size of the area in which they live

In wild populations, individuals most often show a _____ pattern of dispersion.

clumped

In the models that describe population growth, r stands for _____.

per capita population growth rate

The number of individuals that a particular habitat can support with no degradation of that habitat is called _____.

carrying capacity

Which processes increase a population’s size?
a) Births and immigration.
b) Deaths and emigration.
c) Births and deaths.
d) Deaths and immigration.

a

True or false? Factors that determine the per capita rate of increase of a population include the age of breeding and the number of offspring produced each year.

true

Which factor does not affect a habitat’s carrying capacity?
a) Maximum number of individuals in a population.
b) Intensity of predation.
c) Number of nesting sites.
d) Availability of food.

a

Which of the following statements about density-independent growth is true?
a) The per-capita rate of increase may exceed rmax during density-independent growth.
b) Density-independent growth can continue indefinitely in nature.
c) A population that is experiencing density-independent growth levels off at the environment’s carrying capacity.
d) Density-independent growth is also known as exponential growth.

d

Under which of the following conditions would a population most likely experience exponential growth?
a) Environment with a low carrying capacity.
b) Habitat with limited resources.
c) Large number of individuals in the starting population.
d) Young populations with few individuals.

d

Which of the following statements about a population experiencing logistic growth is true?
a) If N is greater than K, the population will shrink.
b) If the K and N values are similar, the amount of available resources is high.
c) If N is less than K, the population will not grow.
d) If the K and N values are far apart, the population will grow very slowly

a

Which of the following is regarded as a density-independent factor in the growth of natural populations?
a) interspecific competition
b) predation
c) flooding
d) emigration
e) intraspecific competition

c

Resource competition, territoriality, disease, and toxic wastes are some of the factors that provide _____ and help regulate population.

negative feedback

Which of these was the first of the major events that stimulated an increase in the size of the human population?
a) the bubonic plague
b) the discovery of antibiotics
c) the Industrial Revolution
d) the discovery of vaccines
e) the advent of agriculture

e

Which of these was the second of the major events that stimulated an increase in the size of the human population?
a) the bubonic plague
b) the discovery of antibiotics
c) the Industrial Revolution
d) the discovery of vaccines
e) the advent of agriculture

c

Which of these was the second of the major events that stimulated an increase in the size of the human population?
a) the discovery of vaccines and antibiotics
b) the discovery of antibiotics
c) the Industrial Revolution
d) the discovery of vaccines
e) the advent of agriculture

a

Which factors permit the human population to continue increasing, without an obvious carrying capacity?
a) expansion of high-density urban areas
b) famines
c) disease outbreaks
d) improvements in medical care

a, d

Ignoring migration, the age structure of a human population likely to increase in size will have what shape?
a) Both a pyramid and a rectangle tapering toward the top result in a population that increases in size.
inverted pyramid
b) Both an inverted pyramid and a rectangle tapering toward the top result in a population that increases in size.
c) a rectangle tapering toward the top
d) pyramid

d

Ignoring migration, the age structure of a human population likely to decrease in size will have what shape?
a) a rectangle tapering toward the top
b) inverted pyramid
c) pyramid
d) Both a pyramid and a rectangle tapering toward the top result in a population that decreases in size.
e) Both an inverted pyramid and a rectangle tapering toward the top result in a population that decreases in size.

b

Ignoring migration, the age structure diagram of a human population likely to maintain a relatively stable size will have what shape?
a) Both an inverted pyramid and a rectangle tapering toward the top result in a population that remains stable in size.
b) a rectangle tapering toward the top
c) Both a pyramid and a rectangle tapering toward the top result in a population that remains stable in size.
d) pyramid
e) inverted pyramid

b

What are population dynamics?

changes in the population through time

Which of the following statements about age pyramids is true?
a) Populations in developed countries grow more quickly than populations in less-developed countries.
b) Age distribution in less-developed countries is bottom-heavy, indicating that these populations are dominated by the very old.
c) Age distribution in developed countries shows an hourglass pattern, with the greatest numbers of people being either very young or very old.
d) Predictions of a population’s future take into account such factors as increasing survivorship and fecundity levels that remain the same.

d

True or false? The growth rate of a certain population increases very quickly for a time and then levels off to zero. The most likely reason that the growth rate leveled off to zero is that the environment reached its carrying capacity.

true

The average age of childbearing in country A is 26, whereas the average age in country B is 30. In each country, the average number of offspring per woman is 3. Which of the following statements about the population growth rate in each country must be true?
a) It is not possible to compare the population growth rates of countries A and B.
b) The population growth rates in countries A and B are the same.
c) The population growth rate in country A is lower than in country B.
d) The population growth rate in country A is higher than in country B.

a

In 1970, the average age of childbearing was 28, and the average number of offspring per woman was 3 in a certain country. In 1980, the average age of childbearing was still 28, but the average number of offspring per woman was 2 in that country. If the death rate in the country remained constant during those years, how did the population growth rate change from 1970 to 1980?
a) The population growth rate stayed the same.
b) The population growth rate increased.
c) The population growth rate decreased.
d) It is not possible to determine the population growth rate.

c

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) A population with an r of 0 will have no births or deaths during the time period under consideration.
b) A population with an r of 0.1 will decrease over time.
c) A population with a positive value of r will grow exponentially.

c

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?
a) rmax declines as N increases.
b) At low values of N, the logistic growth and exponential growth (dN/dt = rN) models predict similar population growth.
c) K is a constant value.

b

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

a

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

a

According to the principle of competitive exclusion, two species cannot continue to occupy the same _____.

ecological niche

Of the choices below, which best describes the effect predation has on the predator/prey organisms involved in the relationship?
a) no effect … benefit
b) benefit … harmed
c) benefit … no effect
d) benefit … benefit
e) harmed … harmed

b

The term used to describe a harmless organism resembling a harmful one is _____.

batesian mimicry

Cellulose-digesting microorganisms live in the guts of termites and ruminant mammals. The microorganisms have a home and food, and their hosts gain more nutrition from their meals. This relationship is an example of _____.

mutualism

Keystone species are those species _____.
a) that have the most biomass in the community
b) that live primarily on or under rocks and stones
c) whose absence would cause major disruption in a community
d) that provide important foods and medicines
e) with the largest number of individuals in a community

c

An organism’s "trophic level" refers to _____.

its food source

Why do we classify lionfish populations near the eastern United States as an invasive species? What suggests that these new populations are not an expansion of the lionfish’s natural range?
a) Lionfish are native to the tropical Pacific. There are no natural water routes of warm water between the Pacific and Atlantic oceans.
b) Lionfish eat only a few specific types of algae that live in isolated regions of the Pacific. If lionfish spread much beyond their native Pacific home, they would have nothing to eat.
c) Lionfish are not good swimmers and have no other mechanisms to spread their populations over great distances.
d) Lionfish are native to cold waters near the tip of South America. They could not survive in the warmer waters between their native areas and the colder waters of the east coast of the United States. So, it is very unlikely that these South American populations naturally spread north.

a

Based upon what we are learning about the lionfish diet, what is most likely going to happen to Caribbean coral reefs invaded by lion fish?
a) The alga populations growing on and near the reef will be greatly reduced, increasing the growth of corals.
b) As lionfish stir up the bottom sediments searching for food, the water will be increasingly cloudy. Cloudy water will hurt the growth of algae and corals growing in the reef.
c) There will be fewer algae eating fish. More algae will grow over and damage corals.
d) Lionfish diets are specific to just a few species of clams. These clams may go extinct in the coral reefs where lionfish have invaded.

c

What characteristics of lionfish contribute to their ability to spread and become established in new areas?
a) A single lionfish female may produce up to 2 million eggs a year. The eggs float for up to a month, spreading the lionfish populations.
b) Lionfish are very good at avoiding predators by hiding in small cracks. Their color is also an excellent form of camouflage. So, lionfish can spread to new locations without being detected.
c) Lionfish typically migrate in large schools to other reefs, where they breed together producing giant egg masses, which cling to the bottom of the coral reef.
d) Lionfish are specialists, consuming just a few types of shrimp, which are widespread in the Caribbean.

a

How did the fish biologists determine the diet of lionfish in the regions where the lionfish have invaded?
a) Biologists kept lionfish in laboratories and experimented with what types of food these captive lionfish would eat.
b) Divers spent thousands of hours watching lionfish around the coral reefs and simply recorded the types of food that the lionfish ate.
c) Biologists examined the contents of the stomachs of lionfish caught in the wild.
d) The fish biologists used many different types of bait to fish for lionfish around coral reefs. The baits that worked best are most likely a part of the lionfish diet.

c

Based upon what we are learning about invasive lionfish populations in the Caribbean and along the Atlantic coast of the United States, these lionfish populations __________.
a) can be eliminated by holding regular lionfish derbies encouraging people to catch as many lionfish as possible
b) can be eliminated by setting traps widely in these regions
c) cannot be eliminated by any means currently known
d) can be controlled by introducing a new lionfish predator from the region where lionfish naturally occur

c

What do plants produce that supports the higher trophic levels of the community?

energy containing food molecules

Caribbean coral reef communities have been strongly influenced by an unknown pathogen that causes white-band disease. How can the effect of white-band disease best be described?
a) Batesian mimicry
b) a cascade event that shifts the entire makeup of the community
c) commensalism
d) the removal of a keystone species
e) mutualism

b

Scientists interested in how populations interact within communities are attempting to determine the species diversity of an island under study. What kind of data would be most helpful to the scientists in determining diversity?
a) The number of different species on the island and the size of the population of each species.
b) The number of trophic levels on the island and the niche of each species.
c) The number of species on the island that are consumers, producers, and decomposers.
d) The relative biomass of each species on the island separated by trophic level.

a

Red-cheeked salamanders are partially protected from predators because of cardiac glycosides they produce from glands on their back. When ingested, cardiac glycosides disrupt normal heart rhythms. A different salamander species, the imitator salamander, also has red cheek patches, but does not produce cardiac glycosides. It does gain protection from predators that have learned to avoid red cheeked salamanders. How does this relationship affect the population dynamics of both species?
a) The red cheeked salamander is positively affected, the imitator is negatively affected.
b) The red cheeked salamander is negatively affected, the imitator is positively affected.
c) Both species are positively affected.
d) Both species are negatively affected.

b

Select the correct statement(s) about a terrestrial food chain.
a) The total biomass of the top trophic level is greatest because the top consumers are large.
b) About 1% of net primary production is available to secondary consumers.
c) Energy is transferred from decomposers to plants to herbivores to carnivores.

b

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

c

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?
a) Riparian vegetation would decline.
b) Elk populations would decline.
c) Bear populations would decline.

b

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

a, c

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

b