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ECOLOGY PRACTICE TEST
Chapter 50
1 . Which of the following investigations is not an example of the study of a biotic factor?
a identifying food sources for an egret population
b
observing interactions among various organisms in a rainforest canopy.
c
investigating how the amount of annual precipitation affects a tree species
d
investigating how an elk population competes for food
e
All of the above are examples of possible biotic factor investigations.
2 . A researcher is investigating how individual foxes are coping with the destruction of part of their habitat
due to construction of a new highway. Which area of ecology is this researcher focusing on?
a organismal ecology
b
population ecology
c
community ecology
d
ecosystem ecology
e
landscape ecology
3 . The most inclusive level of organization in nature is the _____.
a cell
b biosphere
c community
d population
e ecosystem
4 . Why are experiments that involve transplanting species seldom conducted today?
a There are no criteria to determine if they are successful.
b The success of the transplant cannot be measured in one researcher's lifetime.
c The transplanted species are often disruptive to their new communities.
d The potential range of a transplanted species can never be greater than its actual range.
e Species transplants still are a popular experimental tool.
5 . In most cases, the two major climatic factors affecting the distribution of organisms are _____.
a temperature and sunlight
b predators and parasites
c wind and water
d competitors and predators
e water and temperature
6 . A biome is a(n) _____.
a major type of biosphere
b major type of ecosystem
c set of similar communities
d area with a uniform distribution of organisms and abiotic environmental conditions
e specific set of abiotic factors
7 . What are the most abundant animals found in the pelagic zone?
a echinoderms
b marine mammals
c cnidarians
d dinoflagellates
e zooplankton
8 . In lakes and ponds, nutrient enrichment occurs when _____; it can lead to _____.
a levels of dissolved CO2 rise ... bicarbonate levels that are too high to support life
b nutrients from human-altered terrestrial ecosystems are deposited in the water body ... anaerobic
conditions in deeper waters
c toxic substances accumulate in lake sediments ... biohazards in the food web
d pesticides are washed off agricultural land ... decreased aquatic biodiversity
e primary producers are killed by pollution ... starvation of organisms at higher trophic levels
9 . Fire helps to maintain the existence of which biomes?
a savanna, chaparral, temperate grassland, and coniferous forest
b tropical forest, savanna, chaparral, temperate grassland, and coniferous forest
c savanna, desert, chaparral, temperate grassland, and temperate broadleaf forest
d savanna, chaparral, temperate grassland, tundra, and coniferous forest
e savanna and chaparral
10 . In which biome would you most likely find plants that exhibit C4 or CAM photosynthesis?
a tropical forest
b temperate grassland
c tundra
d desert
e coniferous forest
11 . Which of the following areas of study focuses on the exchange of energy, organisms, and materials
between ecosystems?
a population ecology
b organismal ecology
c landscape ecology
d ecosystem ecology
e community ecology
12 . Which statement about dispersal is false?
a Dispersal is a common component of the life cycles of plants and animals.
b Colonization of devastated areas after floods or volcanic eruptions depends on dispersal.
c Dispersal occurs only on an evolutionary time scale.
d Seeds are important dispersal stages in the life cycles of most flowering plants.
e The ability to disperse can expand the geographic distribution of a species.
13 . Imagine some cosmic catastrophe that jolts Earth so that it is no longer tilted. Instead, its axis is
perpendicular to the plane of its orbit around the sun. The most predictable effect of this change would be
a no more night and day.
b a big change in the length of the year.
c a cooling of the equator.
d a loss of seasonal variation at northern and southern latitudes.
e the elimination of ocean currents.
14 . When climbing a mountain, we can observe transitions in biological communities that are analogous
to the changes
a in biomes at different latitudes.
b at different depths in the ocean.
c in a community through different seasons.
d in an ecosystem as it evolves over time.
e across the United States from east to west.
15 . The oceans affect the biosphere in all of the following ways except
a producing a substantial amount of the biosphere's oxygen.
b removing carbon dioxide from the atmosphere.
c moderating the climate of terrestrial biomes.
d regulating the pH of freshwater biomes and terrestrial groundwater.
e being the source of most of Earth's rainfall.
16 . Which lake zone would be absent in a very shallow lake?
a benthic zone
b aphotic zone
c pelagic zone
d littoral zone
e limnetic zone
1 7 . Which of the following is true with respect to oligotrophic lakes and eutrophic lakes?
a Oligotrophic lakes are more subject to oxygen depletion.
b Rates of photosynthesis are lower in eutrophic lakes.
c Eutrophic lake water contains lower concentrations of nutrients.
d Eutrophic lakes are richer in nutrients.
e Sediments in oligotrophic lakes contain larger amounts of decomposable organic matter.
18 . Which of the following is characteristic of most terrestrial biomes?
a annual average rainfall in excess of 250 cm
b a distribution predicted almost entirely by rock and soil patterns
c clear boundaries between adjacent biomes
d vegetation demonstrating stratification
e cold winter months
19 . Which of the following biomes is correctly paired with the description of its climate?
a savanna-cool temperature, precipitation uniform during the year
b tundra-long summers, mild winters
c temperate broadleaf forest--relatively short growing season, mild winters
d temperate grasslands-relatively warm winters, most rainfall in summer
e tropical forests-nearly constant day length and temperature
20 . 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?
a tropical rain forest
b savanna
c taiga
d temperate broadleaf forest
e temperate grassland
Chapter 52
1 . Which of the following is a population?
a a spider and the fly it is about to eat
b all the plants that live near each other in a forest
c the earthworms that live in a grassland plus the earthworms that live in a forest
d all the coyotes on Earth
e all of the redwood trees that live in a forest
2 . To determine the density of a rabbit population, you would need to know the number of rabbits and
_____.
a the factors that limit population growth
b their birth rate
c the size of the area in which they live
d their population growth rate
e their pattern of dispersion
3 . In wild populations, individuals most often show a _____ pattern of dispersion.
a random
b density-dependent
c equilibrium
d uniform
e clumped
4 . Which of the following conditions favors big-bang reproduction?
a intense intraspecific competition
b predictable physical environment
c low rates of offspring survival
d high levels of parental care
e high rate of offspring survival
5 . In the models that describe population growth, r stands for _____.
a population density
b a time interval
c total number of individuals in the population
d per capita population growth rate
e carrying capacity
6 . The number of individuals that a particular habitat can support with no degradation of the habitat is
called _____.
a biotic potential
b survivorship
c niche
d carrying capacity
e community
7 . Which one of the following is regarded as a density-independent factor in the growth of natural
populations?
a intraspecific competition
b interspecific competition
c emigration
d flooding
e predation
8 . A broad-based pyramid-shaped age structure is characteristic of a population that is _____.
a growing rapidly
b at carrying capacity
c stable
d limited by density-dependent factors
e shrinking
9 . Which of the following is the most accurate comment on Earth's carrying capacity for humans?
a K is smaller now than it was a thousand years ago.
b The human population is still a long way from K.
c Our technology has allowed us to keep increasing K.
d When it comes to humans, the concept of K is irrelevant.
e The human population has already exceeded K.
10 . Which statement regarding human population growth is not true?
a
Human population growth was exponential until about 1650.
b
The human population reached 4 billion in 1975. It is expected to double by about 2025.
c
The rate of population growth has slowed since about the 1960s.
d
Changes in population dynamics due to disease and voluntary population control have slowed the
rate of human population growth.
e
All of the above are true.
11 . The observation that members of a population are uniformly distributed suggests that
a the size of the area occupied by the population is increasing.
b resources are distributed unevenly.
c the members of the population are competing for access to a resource.
d the members of the population are neither attracted to nor repelled by one another.
e the density of the population is low.
12 . Population ecologists follow the fate of same-age cohorts to
a determine a population's carrying capacity.
b determine if a population is regulated by density-dependent processes.
c determine the birth rate and death rate of each group in a population
d determine the factors that regulate the size of a population.
e determine if a population's growth is cyclical.
13 . In a population that is growing as described by the logistic growth model,
a the number of individuals added per unit time is greatest when N is close to zero. (The key equation is
dn/dt = rmax N(K - N/K).)
b the per capital growth rate (r) increases as N approaches K.
c population growth is zero when N equals K.
d the population grows exponentially when K is small.
e the birth rate (b) approaches zero as N approaches K.
14 . A population's carrying capacity
a can be accurately calculated using the logistic growth model.
b generally remains constant over time.
c increases as the per capita growth rate (r) decreases.
d may change as environmental conditions change.
e can never be exceeded.
15 . Which pair of terms most accurately describes life-history traits for a stable population of wolves?
a semelparous; r-selected
b semelparous; K-selected
c iteroparous; r-selected
d iteroparous; K-selected
e iteroparous; N-selected
16 .The infant mortality rate is _____ in developing countries than in developed countries
a no different
b about two times higher
c slightly lower
d about three times higher
e more than six times higher
17. Scientific study of the population cycles of snowshoe hare and its predator, the lynx, has revealed that
a the prey population is controlled by predators alone.
b hares and lynx are so mutually dependent that each species cannot survive without the other.
c the most obvious, plausible hypothesis about the cause of population cycles is not necessarily the
correct one.
d both hare and lynx populations are regulated mainly by abiotic factors.
e the hare population is r-selected; the lynx population is K-selected.
18 . The current size of the human population is closest to
(a) 2 billion (b) 4 billion (c) 6 billion (d) 7 billion (e) 9 billion
19 Which of the following statements about human population in developed countries is incorrect?
a Average family size is relatively small.
b The population has undergone the demographic transition.
c Life history is r-selected.
d The survivorship curve is Type I.
e Age distribution is relatively uniform.
20 . A recent study of ecological footprints (described in the text) concluded that
a Earth's carrying capacity for humans is about 10 billion.
b Earth's carrying capacity would increase if per capita meat consumption increased.
c current demand by industrialized countries for resources is much smaller than the ecological footprint of
those countries.
d the ecological footprint of the United States is larger than the ecological capacity of its land.
e it is not possible for technological improvements to increase Earth's carrying capacity for humans.
Chapter 53
1. According to the principle of competitive exclusion, two species cannot continue to occupy the same _.
a environmental habitat
b ecological niche
c territory
d range
e biome
2 Which answer below describes the effect predation has on the organisms involved in the relationship? (
a The answer cannot be determined without more information about the relationship.
b benefit; no effect
c benefit; benefit
d benefit; harmed
e harmed; harmed
3 . The term used to describe a harmless organism resembling a harmful one is _____.
(a) aposematic coloration (b) Batesian mimicry (c) warning coloration (d) (cryptic coloration
e) Müllerian mimicry
4. Cellulose-digesting microorganisms live in the guts of termites and ruminant mammals. The
microorganisms have a home and food, while their hosts gain more nutrition from their meals. This
relationship is an example of _____.
a mutualism
b parasitism
c herbivory
d commensalism
e predation
5 . Which statement about coevolution is not true?
a There is little evidence for true coevolution in most cases of interspecific interactions.
b A possible example of coevolution is the gene-to-gene recognition between a plant species and a
particular virus.
c A possible example of coevolution is the aposematic coloration of tree frogs and the adverse reactions
of various predators.
d Coevolution is defined as reciprocal evolutionary adaptations of two interacting species.
e All of the above are true.
6 . An organism's "trophic level" refers to _____.
a the rate at which it uses energy
b where it lives
c its food source
d whether it is early or late in ecological succession
e the intensity of its competition with other species
7 . Keystone species are those species _____.
a whose absence would cause major disruption in an ecosystem
b that live primarily on or under rocks and stones
c that have provided key foods and medicines
d with the largest number of individuals in an ecosystem
e none of the above
8 which of the following best illustrates ecological succession?
a A mouse eats seeds, and an owl eats the mouse.
b Decomposition in soil releases nitrogen that plants can use.
c Grass grows on a sand dune, followed by shrubs, and then trees.
d Imported pheasants increase, while local quail disappear.
e Overgrazing causes a nutrient loss from soil.
9 . According to MacArthur and Wilson's hypothesis of island biogeography, species immigration and
extinction rates on a particular island correlate to _____.
a how the island formed
b the number of other islands in the archipelago
c the island's size and distance from the mainland
d when the island formed
e all of the above
10 . The idea that the destruction of one species in a community could greatly affect other members of the
community has its roots in the _____ of community structure, which reiterates the_____ of almost 100
years ago.
a rivet model ... integrated hypothesis of community structure
b redundancy model ... integrated hypothesis of community structure
c redundancy model ... individualistic hypothesis of community structure
d rivet model ... individualistic hypothesis of community structure
e individualistic model .... redundancy hypothesis
11 . The feeding relationships among the species in a community determine the community's
a secondary succession.
b ecological niche.
c trophic structure.
d species-area curve.
e species richness.
12 . The competitive exclusion principle states that
a two species cannot coexist in the same habitat.
b competition between two species always causes extinction or emigration of one species.
c competition in a population promotes survival of the best-adapted individuals.
d two species with the exact same niche cannot coexist in a community.
e species that compete usually coevolve.
13 . Keystone predators maintain species diversity in a community by
a competitively excluding other predators.
b preying on the community's dominant species.
c allowing immigration of other predators.
d reducing the number of disruptions in the community.
e coevolving with their prey.
14 . Food chains are usually short mainly because
a only a single species of herbivore feeds on each plant species.
b local extinction of a species causes extinction of the other species in its food chain.
c most of the energy in a trophic level is lost as it passes to the next higher level.
d predator species tend to be less diverse and less abundant than prey species.
e most producers are inedible.
15 . According to the rivet model of community structure,
a species share a community because of similar abiotic requirements.
b communities generally lack sharp geographic boundaries.
c if a species disappears from the community, its role will be assumed by another species.
d all species in a natural community contribute to the community's integrity.
e dependence on a particular type of soil rivets plant species into a tightly networked community.
16 . A community's species diversity is
a increased by frequent massive disturbance.
b increased by stable conditions with no disturbance.
c increased by moderate levels of disturbance.
d increased when humans intervene to eliminate disturbance.
e increased by intensive disturbance by humans.
17 . Which of the following is an example of Müllerian mimicry?
a a butterfly that resembles a leaf
b two poisonous frogs with similar color patterns
c a minnow with spots that look like large eyes
d a beetle that resembles a scorpion
e a carnivorous fish with a wormlike tongue that lures prey
18 . Which of the following could qualify as a top-down control on a grassland community?
a limitation of plant biomass by rainfall amount
b influence of temperature on competition among plants
c influence of soil nutrients on the abundance of grasses versus wildflowers
d effect of grazing intensity by bison on plant species diversity
e effect of humidity on plant growth rates
19 The most plausible hypothesis to explain why species richness is higher in tropical than in temperate
regions is that
a tropical communities are younger.
b tropical regions have more available water and higher levels of solar radiation.
c warmer temperatures cause more rapid speciation.
d biodiversity increases as evapotranspiration decreases.
e tropical regions have very high rates of immigration and very low rates of extinction.
20 . According to the equilibrium model of island biogeography, species richness would be greatest on an
island that is
a small and remote.
b large and remote.
c large and close to a mainland.
d small and close to a mainland.
e environmentally homogeneous.
Chapter 54
1 . The energy for nearly every organism in nearly every ecosystem ultimately comes from _____.
(a) minerals in the soil (b) the sun (c) heat from Earth (d) respiration (e) decomposition
2 . An organism's "trophic level" refers to _____.
(a) the rate at which it uses energy
(b) where it lives
(d) (whether it is early or late in ecological succession
(e) the intensity of its competition with other species
(c) what it eats
3 . Which of the following equations is correct?
(a) NPP = GPP - R (b) R = NPP + GPP (c) GPP = NPP - R (d) NPP = GPP + R (e) none of the above
4 . The relationship between biomass and primary productivity is that _____.
a biomass is the rate of primary productivity
b biomass is the inverse of primary productivity
c biomass is the natural log of primary productivity
d primary productivity is the inverse of biomass
e primary productivity is the rate at which biomass is produced
5 . Why is a diagram of energy flow from trophic level to trophic level shaped like a pyramid?
a Organisms at each level store most of the energy and pass little on.
b There are more producers than primary consumers, and so on.
c Organisms eventually die.
d Most energy at each level is lost, leaving little for the next.
e Secondary consumers are larger than primary consumers, and so on.
6 . 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
a primary consumer
b secondary consumer
c tertiary consumer
d primary and secondary consumers
e secondary and tertiary consumers
7 . Biogeochemical cycles are crucial to ecosystem function because _____.
a they keep the planet warm enough for living things to survive
b nutrients and other life-sustaining molecules are in limited supply and must be continually recycled
c energy flows through ecosystems in one direction only and is eventually dissipated as heat
d they remove poisons and keep them locked up in "sinks"
e they prevent catastrophic extinctions
8 . An ecosystem is unlikely to be limited by the supply of _____ because it is obtained from the air.
(a) water (b) carbon (c) phosphorus (d) calcium (e) nitrogen
9 . Ospreys and other top predators in food chains are most severely affected by pesticides such as DDT
because _____.
a their systems are especially sensitive to chemicals
b of their rapid reproductive rates
c the pesticides become concentrated in their prey
d they cannot store the pesticides in their tissues
e they are directly exposed to pesticides in the air
10 . Which one of the following processes does not increase the concentration of greenhouse gases in the
atmosphere?
a using coal to generate electricity
b increasing the number of cows and sheep to help feed a growing human population
c burning tropical rain forests to clear land for grazing
d failing to repair leaks in natural gas pipelines
e putting salt on roads to prevent ice from forming
11. Which of the following organisms is incorrectly paired with its trophic level?
a cyanobacteria-primary producer
b grasshopper-primary consumer
c zooplankton-primary producer
d eagle-tertiary consumer
e fungi-detritivore
12 . A production pyramid such as the one shown here implies that
a only half the energy in a trophic level is transferred to the
next higher level.
b most of the energy in a trophic level is incorporated into
the next higher level.
c as energy is transferred from one trophic level to another,
about 10% of the energy is lost.
d the most efficient transfer of energy is from producers to
primary consumers.
e eating grain-fed beef is an inefficient way to obtain the
energy captured by photosynthesis.
13 . Nitrifying bacteria participate in the nitrogen cycle mainly by
a converting nitrogen gas to ammonia.
b releasing ammonia from organic compounds, thus returning it to the soil.
c converting ammonia to nitrogen gas, which returns to the atmosphere.
d converting ammonia to nitrate, which is absorbed by plants.
e incorporating nitrogen into amino acids and organic compounds.
14 . The Hubbard Brook watershed deforestation experiment supported all of the following conclusions
except that
a most minerals were recycled within a forest ecosystem.
b the flow of minerals out of a natural watershed was offset by minerals flowing in.
c deforestation increased water runoff.
d the nitrate concentration in waters draining the deforested area became dangerously high.
e calcium levels remained high in the soil of deforested areas.
15 . The main cause of the recent increase in the amount of CO2 in Earth's atmosphere is
a increased worldwide primary production.
b increased worldwide standing crop biomass.
c an increase in the amount of infrared radiation absorbed by the atmosphere.
d the burning of larger amounts of wood and fossil fuels.
e additional respiration by the rapidly growing human population.
16 . Which of the following is a consequence of biological magnification?
a Toxic chemicals in the environment pose greater risk to top-level predators than to primary consumers.
b Populations of top-level predators are generally smaller than populations of primary consumers.
c The biomass of producers in an ecosystem is generally higher than the biomass of primary consumers.
d Only a small portion of the energy captured by producers is transferred to consumers.
e The amount of biomass in the producer level of an ecosystem decreases if the producer turnover time
increases.
17 . Which of these ecosystems has the lowest net primary production per square meter?
(a) a salt marsh (b) an open ocean (c) a coral reef (d) a grassland (e) a tropical rain forest
18 . Tropical forest soils contain comparatively low levels of mineral nutrients because
a the standing crop biomass of tropical forests is comparatively small.
b tropical soil microorganisms do not break down organic matter as efficiently as temperate zone soil
microorganisms do.
c organic matter decomposes more rapidly and plants assimilate soil nutrients more rapidly in the tropics.
d nutrients cycle more slowly in the tropics.
e many nutrients are destroyed by high temperatures in the tropics.
19 . Imagine that you test samples of coastal water polluted with runoff from farms and find detectable
levels of phosphates, but not of nitrogen. In a follow-up experiment, you find that if you enrich some of
your samples with nitrogen, algal growth is much greater than in unenriched, control samples. Enriching
samples with phosphate, however, does not increase algal growth. From your results, you can conclude
a algae populations in these waters could be reduced by decreasing phosphate runoff.
b eutrophication of these waters could be reduced by adding nitrogen.
c algae populations in these waters are kept low by high levels of phosphorus.
d nitrogen is the limiting nutrient in these waters.
e phosphate is the limiting nutrient in these waters.
20 . Which of the following has the greatest effect on the rate of chemical cycling in an ecosystem?
a the ecosystem's rate of primary production
b the production efficiency of the ecosystem's consumers
c the rate of decomposition in the ecosystem
d the trophic efficiency of the ecosystem
e the location of the nutrient reservoirs in the ecosystem
Chapter 55
1. Current rates of extinction may be _____ those of the past 100,000 years.
(a) 100 times higher than (b) 50 times lower than (c) the same as (d) 10 times higher than
(e) 1,000 times higher than
2 . The primary cause of the extinction of native species of cichlids in Lake Victoria is _____.
a a decrease in the lake's size due to the use of water in irrigation
b recreational use
c the introduction of an exotic predator
d fragmentation
e PVA
3 . The single greatest current threat to biodiversity is _____. (a) global warming (b) introduced species
(c) overhunting (d) habitat destruction (e) reduced genetic variability
4 . In a population of 3,000 adult males and 7,000 adult females, where all adult females and 10% of adult
males mate, the effective population size would be approximately _____.
(a) 8,400 (b) 600 (c) 1,150 (d) 840 (e) 11,507
5 . Which of the following does not apply to a population with a low effective population size?
(a) genetic drift
(b) increased genetic diversity
(c) reduced heterozygosity
(d) increased homozygosity
(e) inbreeding
6 . The estimated density or number of individuals needed for a species to maintain or increase its numbers
in a region is the _____.
a minimum viable population (MVP)
b stochastic population
c metapopulation
d Hardy-Weinberg equilibrium
e endemic population
7. Landscape ecology addresses _____.
a metapopulation studies
b the populations found in the same environment
c the trees and flowers planted around human dwellings
d patterns of landscape use and biodiversity conservation
e source and sink populations
8 . Edge species _____.
a decrease biodiversity
b exist only in areas that have been altered by humans
c require the unique homogenous edge environment
d are all nest parasites
e may require conditions found in both of the bordering ecosystems
9. Connections between habitat fragments are referred to as _____.
(a) movement corridors (b) highways (c) minimum dynamic areas (d) (riparian areas (e) landscapes
10 . Biodiversity hot spots are _____.
a distributed evenly throughout the biosphere
b regions with the potential for high levels of extinction
c the same for all groups of organisms
d regions where thermophilic species thrive
e relatively resistant to environmental degradation due to their large number of species
11 . Ecologists conclude there is a biodiversity crisis because
a biophilia causes humans to feel ethically responsible for protecting other species.
b scientists have at last discovered and counted most of Earth's species and can now accurately calculate
the current extinction rate.
c the current extinction rate is far higher than the rate at any time in the past 100,000 years.
d many potential life-saving medicines are being lost as species become extinct.
e there are too few biodiversity hot spots.
12 . Which of the following directly addresses the growing concern over the loss of ecosystem diversity?
a the small-population approach
b restoration ecology
c the declining-population approach
d increasing effective population sizes of endangered species
e managing populations to increase genetic diversity
13 . What is the effective population size (Ne) of a population of 50 strictly monogamous swans that
includes 40 males and 10 females? (a) 50 (b) 40 (c) 30 (d) 20 (e) 10
1 4 . One characteristic that distinguishes a population in an extinction vortex from most other populations
is that
a its habitat is fragmented.
b it is a rare, top-level predator.
c its effective population size is much lower than its total population size
d its genetic diversity is very low.
e it is not well adapted to edge conditions.
15 . The discipline that applies ecological principles to returning degraded ecosystems to more natural
states is known as
a population viability analysis.
b landscape ecology.
c conservation ecology.
d restoration ecology.
e resource conservation.
16 . What is the single greatest threat to biodiversity?
a overexploitation of commercially important species
b introduced species that compete with or prey on native species
c pollution of Earth's air, water, and soil
d disruption of trophic relationships as more and more prey species become extinct
e habitat alteration, fragmentation, and destruction
17 . Which of the following is not a step in the declining-population approach to conservation biology?
a Gather data to determine whether a population is in decline.
b Implement a conservation plan at the outset of a study, as it is too risky to wait until data are gathered
and analyzed.
c Develop multiple alternative hypotheses for the cause of population decline.
d Include human activities and natural events as possible causes of a population decline.
e Test the hypotheses for the cause of the decline, beginning with the hypothesis most likely to be correct.
18 . Which of the following strategies would most rapidly increase the genetic diversity of a population in
an extinction vortex?
a Capture all remaining individuals in the population for captive breeding followed by reintroduction to
the wild.
b Establish a reserve that protects the population's habitat.
c Introduce new individuals transported from other populations of the same species.
d Sterilize the least fit individuals in the population.
e Control populations of the endangered population's predators and competitors.
19 . Of the following statements about protected areas that have been established to preserve biodiversity,
which one is not correct?
a About 25% of Earth's land area is now protected.
b National parks are one of many types of protected area.
c Most protected areas are too small to protect species.
d Management of a protected area should be coordinated with management of the land surrounding the
area.
e It is especially important to protect biodiversity hot spots.
20 . What is the Sustainable Biosphere Initiative?
a a plan to convert all natural ecosystems in the biosphere to carefully engineered ones
b a research agenda to study biodiversity and support sustainable development
c a conservation practice that sets up zoned reserves surrounded by buffer zones
d the declining-population approach to conservation that seeks to identify and remedy causes of species'
declines
e a program that uses adaptive management to experiment and learn while working with disturbed
ecosystems