Test 6
Approximately what proportion of the radiant energy entering an ecosystem is used in photosynthesis?
1%
Refer to the accompanying figure. A population that produces a large number of offspring, but the offspring must survive independently, would be represented by the curve labeled
A
Which statement best describes a typical food chain?
An owl has a positive impact on the grass population.
Refer to the accompanying figure. At which point on the graph is the population increasing exponentially?
B
Which statement about biomass is FALSE?
Biomass reduction from one trophic level to the next is approximately 50%.
Which country would be expected to have the greatest species richness per unit area?
Brazil
On the accompanying figure, identify the point that indicates the carrying capacity for this population
D
Which statement about Earth's biomes is FALSE?
Deserts have less rainfall due to their distance from the ocean.
What is the least likely effect of fires on organisms?
Fire instigates the growth of shade-tolerant plants.
The event in human history that changed the natural balance of the carbon cycle was the:
Industrial Revolution
The Southern Hemisphere has no equivalent of the boreal forest of the north. Why?
It has no land in the corresponding latitudes
Many poisonous snakes share warning colors of red, yellow, and black. This is an example of:
Müllerian mimicry.
____ is the least frequent of the dispersal patterns seen in nature.
Random dispersion
An example of mutualism is:
Rhizobium and legumes.
____ are good habitats where local reproductive success is greater than local mortality.
Source habitats
If you were to study all of the insect-eating birds in a forest, you would see that many birds eat insects, yet you may not see any evidence of competition. What is the most probable explanation?
The birds are exhibiting resource partitioning.
Four of the five statements listed below apply to the types of ecological pyramids. Which one is FALSE?
The pyramid of biomass show actual biomass reduction from one trophic level to the next
Which statement reflects a key concept about ecosystems?
There is a one-way flow of energy through the food webs of ecosystems.
Which of the following will prevent the further buildup of greenhouse gases?
Use your automobile less, and ride a bicycle more.
Clumped dispersion is often influenced by:
a patchy distribution of resources.
Which of the following consists of organisms, all of which share a common gene pool?
a population
The percentages of a population at different ages are known as the:
age structure
In Experimental Condition 1 of the accompanying figure, the distribution of Balanus suggests: that
an unfavorable environmental factor kept Balanus from extending higher into the intertidal area.
Density-independent factors:
are typically abiotic.
Keystone species:
are typically not the most abundant species in the community.
Which step of the nitrogen cycle is not performed by most bacteria?
assimilation
In the accompanying figure, the gull has the highest concentration of DDT because it is:
at the top of the food chain
Organisms that manufactures their own food are known as:
autotrophs
Which set of values would result in a population with a growth rate of zero?
b = 1000, d = 500, i = 500, e = 1000
At zero population growth:
b=d
The community found on a rotting log would include:
bacteria
What bird, due to human efforts, has been removed from the endangered species list and is now listed as threatened?
bald eagle
The graph in the accompanying figure would best be described as:
being a J-shaped curve characteristic of exponential growth
Sponges and brittle stars are members of the ____ category of organisms
benthos
The accompanying figure is a good illustration of:
biological magnification
Stratospheric ozone is important because it:
blocks solar UV radiation.
Which organism would be found exclusively in the benthic environment?
bloodworms
Climates characteristic of the Mediterranean region are also common in:
california
To date, humans have interfered with all of the biogeochemical cycles on Earth, but this interference has been of the greatest magnitude, in terms of human-induced changes in climate, in the:
carbon cycle
The major components of Earth's atmosphere, from the lowest concentration to the greatest concentration, are:
carbon dioxide, oxygen, and nitrogen
The ____ biome is characterized by plants that are particularly well adapted to periodic fires.
chaparral
Which animal is incorrectly matched with its desired product?
cheetah-liver
The organisms associated with patches of floating ocean vegetation would be an example of:
clumped dispersion
Traditionally, most ecologists have assumed that community stability is a consequence of:
community complexity.
In a lake, a certain native species of zooplankton is found evenly distributed in the water column. After introduction of a different species of zooplankton, the native species is only found in the shallow water zone. This is most likely an illustration of:
competitive exclusion
Commercial logging:
cuts trees primarily for export.
Based on the accompanying figure, the decline in the moose population in 1996 was most likely due to a(n):
decline in the food supply
The Coriolis effect results in the:
deflection of moving air due to the rotation of Earth.
Which factors are an example of a negative feedback system?
density dependent
Overgrazing in savannas by domestic animals has contributed to its conversion into:
desert
Today, the major danger to species is:
destruction of habitats
Headwater streams depend primarily on ____ as an energy input.
detritus
Pyramids of numbers are of limited usefulness because they:
do not indicate the biomass of the organisms at a given time.
An organism's role within the structure and function of a particular community is its:
ecological niche
Community ____ is the description and analysis of patterns and processes within a community.
ecology
Species diversity is often very high in the region between two distinct communities, known as a(n):
ecotone
What key factor limits the number of trophic levels in an ecosystem?
energy loss
The ability to meet humanity's current needs without compromising the ability of future generations to meet their needs is:
environmental sustainability.
Characteristics of headwaters include:
fast flow, high oxygen, and streamlined animal bodies.
The potential capacity to produce offspring is called:
fecundity.
In the United States, the largest group of endangered species is:
flowering plants
Biologists in which of the following applied disciplines must understand population ecology?
forestry, agronomy, and wildlife management
Mycorrhizae are associations between:
fungi and plant roots
Building roads, parking lots, buildings and bridges all contribute to:
habitat destruction
The breakup of large areas of habitat into small, isolated patches is called:
habitat fragmentation
The tropical rain forest biome is characterized by:
high density of plants, but nutrient poor soil.
In which of the following habitat types would species diversity be expected to be relatively low?
high environmental stress
Harmful introduced species usually come into an area by:
human beings
Ecologist James H. Brown of the University of New Mexico has addressed species composition and richness in experiments conducted since 1977 in the Chihuahuan desert of southeastern Arizona. In one experiment, the removal of three dominant species, all kangaroo rats, from several plots resulted in an increased diversity of other rodent species. This increase was ascribed both to lowered competition for food and also to an altered habitat, because the abundance of grass species ____ after the removal of the kangaroo rats.
increased
Niches apply to:
individual species
Competitive exclusion is a result of:
interspecific competition
Foreign species that have negative effects on native species are called:
invasive species
The exact elevation at which the treeline occurs depends on the ____ and ____.
latitude; distance from the ocean
The most productive region of a lake is the ____ zone.
littoral
Pollution affects species diversity, thus the species richness of a highly polluted stream is ____ compared with that of a nearby pristine stream.
low
The species richness of high-latitude communities is ____ compared with that of low-latitude communities.
low
Destructive outbreaks of pests are ____ in cultivated fields, which are low-diversity communities, than in natural communities with greater species richness.
more common
Tundra soils are usually ____ and have ____ in the uppermost layer of soil
nutrient poor; little organic litter
The ____ contains the greatest volume of ocean water.
oceanic province
There are no trees in the tundra because:
of limited root penetration due to permafrost.
The best definition of population density is the number of individuals:
of one species in a given area at a given time
Primary succession may be seen:
on new lava or on sand dunes.
In situ conservation includes:
parks and reserves.
Which nutrient cycle does not have a gaseous phase?
phosphorus cycle
Fixation of carbon is accomplished by:
photosynthetic organisms
Which are the three main roles played by organisms in community life?
producer, consumer, decomposer
The atmosphere performs several essential ecological functions. One of these is to:
protect Earth from most ultraviolet radiation
Resource partitioning may include which of the following?
relocating nesting sites
The use of the principles of ecology to return a degraded environment to as close as possible of a functional state is called:
restoration ecology.
Animals that are being hunted (often illegally) for body parts thought to have medicinal value include:
rhinos and bears.
Which factor is most important in determining the distribution of organisms in aquatic biomes?
salinity
What two abiotic factors are considered to most affect organisms?
temperature and water
Perhaps the biggest problem associated with the Endangered Species Act as it currently stands is that it:
tends to protect a limited number of organisms
Transpiration is most closely associated with:
terrestrial plants
Net primary productivity represents:
the amount of biomass in excess of that needed to support plant cell respiration.
Fossil fuels, such as coal and oil, are derived from which biogeochemical cycle?
the carbon cycle
When the death of species is less imminent, but the population of a particular species is quite small, it is defined as being:
threatened
Which biome has the fewest types of species?
tundra
The moose population on Isle Royale is an example of:
intraspecific exploitation competition.
GPP, or Gross Primary Productivity:
is the total energy captured from the sun through photosynthesis
Iteroparity is common in which of the following organisms?
perennial herbaceous plants
Based on the temperature range and precipitation, the area on the accompanying figure labeled as 3 represents which of the following biomes?
savanna
What is the third trophic level of a food chain?
secondary consumers
The orderly replacement of one community by another is known as:
succession
Which biome has the least primary productivity?
tundra
Which biome has the shortest growing season?
tundra
Which biome is characterized by weasels, gray wolves, ptarmigan, musk oxen, and lemmings?
tundra
What would be the growth rate (r) of an island population of 1000 that has 30 births per 100 population, 20 death per 100 population, 5 immigrants per 100 population, and 10 emigrants per 100 population?
+50
Based on the accompanying figure, which of the following age intervals has the highest death rate?
0-1
Which of the lakes in the accompanying figure may experience turnover?
1 and 3
According to the accompanying figure, global warming would result from an increase in which of the labeled components?
4
The enzyme nitrogenase is rather unique, as it specifically functions in the:
absence of oxygen
Adaptations found in inhabitants of the rocky intertidal zone include:
an anchor or some other means of attachment.
A biodiversity hotspot is a(n):
an area rich in endemic species and high in human population.
An unprotected area of naturally occurring plant and animal assemblages that is surrounded by unsuitable territory due to development or habitat destruction is referred to by biologists as:
an island
Marine snow is a major source of energy for the ____ region of the ocean.
aphotic
The ____ covers approximately 11% of Earth's land and contains numerous lakes and ponds.
boreal forest
According to the data in the accompanying figure, the cause of the decline of the wolf population in 1982 was:
cannot be determined from the data provided
Deforestation in the boreal forests is due primarily to:
clear-cut logging for industrial wood.
The equation that would best describe the curve in the accompanying figure is:
dN / dt = rN.
A linear depiction of energy flow in an ecosystem is a(n):
food chain
The ____ niche is the broadest role that an organism can potentially have in a community.
fundamental
Which of the following is not a predicted outcome of climate change?
global average sea level decreasing
El Niño-Southern Oscillation has resulted in:
global weather changes
Which of the following is a predicted effect of continued global warming?
greater impact on plant species in particular
In an ecosystem, which measure of energy is the largest in amount or rate?
gross primary productivity
In the accompanying figure, the process labeled as 3 illustrates an action that is reduced by greenhouse gas accumulation. What is this action?
heat radiation into space
Slash-and-burn agriculture:
is practiced by subsistence farmers.
The Montreal Protocol:
limited production of CFCs.
One reason that the realized niche and fundamental niche are not typically the same is:
limiting resources
The almost complete loss of the American chestnut tree to the chestnut blight fungus had ____ ecological impact on the moderately diverse Appalachian woodlands of which it was formerly a part.
little
Some animals are facing extinction as a direct result of deliberate efforts to exterminate them because of their perceived harm to economically useful species. Examples of these include:
mountain lions and wolves
The relationship between reef-building coral animals and zooxanthellae is classified as:
mutualism
Refer to the accompanying figure. Assuming the pattern remains the same, what will the population experience in 50 years?
negative growth
Which of the following relationships is incorrectly paired?
nesting seabirds−random dispersion
An example of a density-dependent factor that influences the size of a population is:
parasites
Microscopic algae typically fall under the classification of:
phytoplankton.
Which of the following series correctly represents the hierarchical organization within ecology?
population → community → ecosystem → biosphere
Which pair best represents photosynthetic organisms?
primary producer and autotroph
Species richness is ____ when any one species enjoys a position of dominance.
reduced
Biological diversity is an index of the variety of living organisms in an ecosystem, and includes:
species richness, genetic diversity, and ecosystem diversity.
The problems associated with slash-and-burn agriculture are most closely related to:
subsistence agriculture.
The logistic equation:
takes into account the carrying capacity of the environment.
The greatest proportion of which two biomes have been converted to agriculture?
temperate deciduous forest and temperate grassland
Currently, much commercial lumber and wood products come from which biome?
temperate rain forest
The ____ biome has the greatest species richness of the terrestrial biomes.
tropical rain forest
Which biome has the longest growing season?
tropical rain forest
Which habitat would most likely have the greatest species richness?
tropical rain forest
When r = 0.00001, the population size:
will increase
An example of ex situ conservation is a:
zoo
