Trees are not usually found in the tundra biome because of
A) insufficient annual precipitation.
B) acidic soils.
C) extreme winter temperatures.
D) overbrowsing by musk ox and caribou.
E) permafrost.

permafrost.

Which of the following levels of ecological organization is arranged in the correct sequence
from most to least inclusive?
A) community, ecosystem, individual, population
B) ecosystem, community, population, individual
C) population, ecosystem, individual, community
D) individual, population, community, ecosystem
E) individual, community, population, ecosystem

ecosystem, community, population, individual

Which of the following choices includes all of the others in creating global terrestrial
climates?
A) differential heating of Earth's surface
B) ocean currents
C) global wind patterns
D) evaporation of water from ocean surfaces
E) Earth's rotation on its axis

differential heating of Earth's surface

Why is the climate drier on the leeward side of mountain ranges that are subjected to
prevailing winds?
A) Deserts create dry conditions on the leeward side of mountain ranges.
B) The sun illuminates the leeward side of mountain ranges at a more direct angle, converting to
heat energy, which evaporates most of the water present.
C) Pushed by the prevailing winds on the windward side, air is forced to rise, cool, condense,
and drop its precipitation, leaving drier air to descend the leeward side.
D) Air masses pushed by the prevailing winds are stopped by mountain ranges and the moisture
is used up in the stagnant air masses on the leeward side.
E) More organisms live on the sheltered, leeward side of mountain ranges where their utilization
of water lowers the amount available when compared to the windward side.

Pushed by the prevailing winds on the windward side, air is forced to rise, cool, condense,
and drop its precipitation, leaving drier air to descend the leeward side.

What would be the effect on climate in the temperate latitudes if Earth were to slow its rate of
rotation from a 24-hour period of rotation to a 48-hour period of rotation?
A) Seasons would be longer and more distinct (colder winters and warmer summers).
B) There often would be a smaller range between daytime high and nighttime low temperatures.
C) Large-scale weather events such as tornadoes and hurricanes would no longer be a part of
regional climates.
D) Winter seasons in both the northern and southern hemispheres would have more abundant and
frequent precipitation events.
E) There often would be a larger range between daytime high and nighttime low temperatures.

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

Palm trees and subtropical plants are commonplace in Land's End, England, whose latitude is
the equivalent of Labrador in coastal Canada, where the local flora is subarctic. Which statement
best explains why this apparent anomaly exists between North America and Europe?
A) Labrador does not get enough rainfall to support the subtropical flora found in Land's End.
B) Regions such as Labrador are actually colder than England because colder arctic air is pulled
down to eastern North America and not to England.
C) Rainfall fluctuates greatly in England; rainfall is consistently high in Labrador.
D) Labrador is too windy to support tall plants, such as palm trees.
E) Labrador receives sunlight of lower duration and intensity than does Land's End.

Regions such as Labrador are actually colder than England because colder arctic air is pulled
down to eastern North America and not to England.

In mountainous areas of western North America, north-facing slopes would be expected to
A) receive more sunlight than similar southern exposures.
B) be warmer and drier than comparable southern-exposed slopes.
C) consistently be steeper than southern exposures.
D) support biological communities similar to those found at lower elevations on similar south-
facing slopes.
E) support biological communities similar to those found at higher elevations on similar south-
facing slopes.

support biological communities similar to those found at higher elevations on similar south-
facing slopes.

Deserts typically occur in a band around 30 degrees north and south latitude because
A) descending air masses originating from the tropics tend to be dry.
B) trade winds have little moisture.
C) moisture-laden air is heavier than dry air and is not carried to these latitudes.
D) ascending air from these regions tends to be moist, removing available water and creating a
desert.
E) these locations get the most intense solar radiation of any location on Earth.

descending air masses originating from the tropics tend to be dry.

Which of the following events might you predict to occur if the tilt of Earth's axis relative to
its plane of orbit was increased to 33 1/2 degrees?
A) Summers and winters in the United States would likely become warmer and colder,
respectively.
B) Winters and summers in Australia would likely become less distinct seasons.
C) Seasonal variation at the equator might decrease.
D) Both northern and southern hemispheres would experience summer and winter at the same
time.
E) Both poles would experience massive ice melts.

Summers and winters in the United States would likely become warmer and colder,
respectively.

Imagine some cosmic catastrophe jolts Earth so that its axis is perpendicular to the orbital
plane between Earth and the sun. The most obvious effect of this change would be
A) the elimination of tides.
B) an increase in the length of night.
C) an increase in the length of a year.
D) a decrease in temperature at the equator.
E) the elimination of seasonal variation.

the elimination of seasonal variation.

The main reason polar regions are cooler than the equator is that
A) there is more ice at the poles.
B) sunlight strikes the poles at a lower angle.
C) the poles are farther from the sun.
D) the polar atmosphere is thinner and contains fewer greenhouse gases.
E) the poles are permanently tilted away from the sun.

sunlight strikes the poles at a lower angle.

Which of the following environmental features might influence microclimates?
A) forest canopy
B) freshly plowed field
C) log on the forest floor
D) large boulder
E) All of the options are correct.

All of the options are correct.

Generalized global air circulation and precipitation patterns are caused by
A) rising, warm, moist air masses that cool and release precipitation as they rise and then, at high
altitude, cool and sink back to the surface as dry air masses after moving north or south of the
tropics.
B) air masses that are dried and heated over continental areas that rise, cool aloft, and descend
over oceanic areas followed by a return flow of moist air from ocean to land, delivering high
amounts of precipitation to coastal areas.
C) polar, cool, moist high-pressure air masses from the poles that move along the surface,
releasing precipitation along the way to the equator where they are heated and dried.
D) the revolution of Earth around the sun.
E) mountain ranges that deflect air masses containing variable amounts of moisture.

rising, warm, moist air masses that cool and release precipitation as they rise and them at high altitude, cool and sink back to the surface as dry air masses after moving north or south of the tropics

Air masses formed over the Pacific Ocean are moved by prevailing westerlies where they
encounter extensive north-south mountain ranges, such as the Sierra Nevadas and the Cascades.
Which statement best describes the outcome of this encounter between a landform and an air
mass?
A) The cool, moist Pacific air heats up as it rises, releasing its precipitation as it passes the tops
of the mountains, and this warm, now dry air cools as it descends on the leeward side of the
range.
B) The warm, moist Pacific air rises and cools, releasing precipitation as it moves up the
windward side of the range, and this cool, now dry air mass heats up as it descends on the
leeward side of the range.
C) The cool, dry Pacific air heats up and picks up moisture from evaporation of the snowcapped
peaks of the mountain range, releasing this moisture as precipitation when the air cools while
descending on the leeward side of the range.
D) These air masses are blocked by the mountain ranges, producing high annual amounts of
precipitation on the windward sides of these mountain ranges.
E) These air masses remain essentially unchanged in moisture content and temperature as they
pass over these mountain ranges.

The warm, moist Pacific air rises and cools, releasing precipitation as it moves up the
windward side of the range, and this cool, now dry air mass heats up as it descends on the
leeward side of the range.

Coral reefs can be found on the southeast coast of the United States but not at similar
latitudes on the southwest coast. Differences in which of the following most likely account for
this?
A) sunlight intensity
B) precipitation
C) day length
D) ocean currents
E) salinity

ocean currents

What is the limiting factor for the growth of trees in the tundra?
A) low precipitation
B) lack of sunlight
C) insufficient minerals in bedrock
D) pH of soils
E) permafrost

permafrost

In which of the following terrestrial biome pairs are both dependent upon periodic burning?
A) tundra and coniferous forest
B) chaparral and savanna
C) desert and savanna
D) tropical forest and temperate broadleaf forest
E) grassland and tundra

chaparral and savanna

Fire suppression by humans
A) will always result in an increase in species diversity in a given biome.
B) can change the species composition within biological communities.
C) will result ultimately in sustainable production of increased amounts of forest products for
human use.
D) is necessary for the protection of threatened and endangered forest species.
E) is a management goal of conservation biologists to maintain the healthy condition of forest
communities.

can change the species composition within biological communities.

Which of the following statements best describes the interaction between fire andecosystems?
A) The likelihood of a wildfire occurring in a given ecosystem is highly predictable over the
short term.
B) Many kinds of plants and plant communities have adapted to frequent fires.
C) The suppression of forest fires by man has prevented certain communities, such as grasslands,
from reaching their climax stage.
D) Chaparral communities have evolved to the extent that they rarely burn.
E) Fire is unnatural in ecosystems and should be prevented.

Many kinds of plants and plant communities have adapted to frequent fires.

Imagine that a deep temperate zone lake did not "turn over" during the spring and fall
seasons. Based on the physical and biological properties of limnetic ecosystems, what would be
the difference from normal seasonal turnover?
A) The lake would be uniformly cold during the winter and summer.
B) The lake would fail to freeze over in winter.
C) An algal bloom would result every spring.
D) The lake would suffer a nutrient depletion in its surface layers.
E) The pH of the lake would become increasingly alkaline.

The lake would suffer a nutrient depletion in its surface layers.

Which marine zone has the lowest rates of primary productivity (photosynthesis)?
A) pelagic
B) abyssal
C) neritic
D) continental shelf
E) intertidal

abyssal

If a meteor impact or volcanic eruption injected a lot of dust into the atmosphere and reduced
the sunlight reaching Earth's surface by 70% for one year, which of the following marine
communities most likely would be least affected?
A) deep-sea vent
B) coral reef
C) intertidal
D) pelagic
E) estuary

deep-sea vent

Which statement describes how climate might change if Earth was 75% land and 25% water?
A) Terrestrial ecosystems would likely experience more precipitation.
B) Earth's daytime temperatures would be higher and nighttime temperatures lower.
C) Summers would be longer and winters shorter at midlatitude locations.
D) Earth would experience an unprecedented global warming.
E) More terrestrial microclimates would be created because of daily fluctuations in climate.

Earth's daytime temperatures would be higher and nighttime temperatures lower.

Which of the following examples of an ecological effect leading to an evolutionary effect is
most correct?
A) When seeds are not plentiful, trees produce more seeds.
B) A few organisms of a larger population survive a drought and then these survivors emigrate to
less arid environments.
C) A few individuals with denser fur survive the coldest days of an ice age, and the reproducing
survivors of the ice age all have dense fur.
D) Fish that swim the fastest in running water catch the most prey and more easily escape
predation.
E) The insects that spend the most time exposed to sunlight have the most mutations.

A few individuals with denser fur survive the coldest days of an ice age, and the reproducing
survivors of the ice age all have dense fur.

Which of the following are important biotic factors that can affect the structure and
organization of biological communities?
A) precipitation, wind
B) nutrient availability, soil pH
C) predation, competition
D) temperature, water
E) light intensity, seasonality

predation, competition

A certain species of pine tree survives only in scattered locations at elevations above 2,800 m
in the western United States. To understand why this tree grows only in these specific places, an
ecologist should
A) conclude that lower elevations are limiting to the survival of this species.
B) study the anatomy and physiology of this species.
C) investigate the various biotic and abiotic factors that are unique to high altitude.
D) analyze the soils found in the vicinity of these trees, looking for unique chemicals that may
support their growth.
E) collect data on temperature, wind, and precipitation at several of these locations for a year.

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