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Exploring Our World

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Exploring Our World Powered By Docstoc
					                                                    Chapter Introduction
                                                    Section 1: Forces Shaping
                                                               the Earth
                                                    Section 2: Landforms and
                                                               Water Resources
                                                    Section 3: Climate Regions
                                                    Section 4: Human-
                                                               Environment
                                                               Interaction
                                                    Summary

Bill Hatcher/National Geographic Image Collection
Place Think about the
characteristics of the area
where you live. How does the
land look? Is there a large
body of water nearby? What
is the climate like? Each
place on the Earth is unique,
with its own special
characteristics. What kinds
of geographic
characteristics define the
region where you live?
Section 1:
Forces Shaping the Earth
Physical processes shape
the Earth’s surface. Forces
from within and the actions of
wind, water, and ice have
shaped Earth’s surface.
Section 2: Landforms and
Water Resources
Geographic factors
influence where people
settle. Physical features
determine where people live.
Section 3:
Climate Regions
Geographers organize the
Earth into regions that
share common
characteristics.
Geographers use climate to
define world regions.
Section 4: Human-
Environment Interaction
All living things are
dependent upon one
another and their
surroundings for survival.
Human actions greatly affect
the natural world.
Physical processes shape the Earth’s
surface.
Content Vocabulary
• core        • plate tectonics
• mantle      • earthquake
• magma       • fault
• crust       • weathering
• continent   • erosion
Academic Vocabulary
• release    • accumulate
• constant
Have you ever been in an
earthquake?
A. Yes
B. No
                               A. A
                               B. B
                           0%     0%

                           A




                                  B
Eyewitnesses to the 2004 tsunami in Indonesia saw
animals running from the coastline soon before the
waves hit. Later, rescue workers and investigators were
surprised to find very few dead animals among the
devastation. Scientists speculate that animals can hear,
smell, and feel subtle environmental changes that
serve as warnings to flee.
Inside the Earth
           The Earth is made up of
           several layers that have
           different characteristics.
Inside the Earth (cont.)
• The Earth has layers like a melon or a
  baseball. The center is a dense solid
  core of hot iron mixed with other metals
  and rock.
• The next layer, the outer core, is so hot
  that the metal has melted into a liquid.
• Around the core is a layer of hot dense
  rock about 1,770 miles thick
  called the mantle.
                            Earth’s Layers
Inside the Earth (cont.)
• The area nearest the core is solid, but the
  rock in the outer mantle can be moved,
  shaped, and melted.
• Melted rock from the mantle is called
  magma.
• It flows to the surface during a volcanic
  eruption. Once it reaches the surface,
  magma is called lava.
Inside the Earth (cont.)
• A rocky shell forms the Earth’s surface
  and is called the crust.
• This uppermost layer includes the ocean
  floors and seven land areas known as
  continents.
Which of the following is NOT the
name of a continent?
A. Europe
B. Africa
C. Central America                   A.   A
D. Australia                         B.   B
                               0%    C.
                                    0%    C
                                          0%   0%
                           A
                                     D.   D
                                    B




                                          C




                                               D
Shaping the Earth’s Surface
          Forces acting both inside and
          outside the Earth work to
          change the appearance of the
          Earth’s surface.
Shaping the Earth’s Surface (cont.)
• Because the Earth’s crust is in slow,
  constant motion, it changes over time.
• Old mountains are worn down, while new
  mountains grow taller. The continents
  move as well.
• By studying plate tectonics, you can
  understand how the continents were
  formed and why they move.

                 Tectonic Plate Boundaries
Shaping the Earth’s Surface (cont.)
• Each continent sits on one or more large
  land bases called plates.
• As these plates move, the continents also
  move.
• This movement is called continental drift.
  The drift can be as little 1 (2.54 cm) inch to
  as much as 7 inches (17.78 cm) per year.
Shaping the Earth’s Surface (cont.)
• Sometimes the plates pull away from each
  other, and sometimes they collide.
• When plates collide, the land where the
  plates meet rises and forms mountains.
• Collisions of continental and oceanic
  plates cause magma to erupt. When the
  magma hardens, the result is volcanic
  mountains.
Shaping the Earth’s Surface (cont.)
• Earthquakes are sudden and violent
  movements of the Earth’s crust.
• They are common in areas such as the
  Pacific Ocean. Here the collision of ocean
  and continental plates makes the Earth’s
  crust unstable.
Shaping the Earth’s Surface (cont.)
• When plates move alongside each other,
  the movement makes cracks in the Earth’s
  crust called faults.
• Movements along faults may happen in
  sudden bursts that cause earthquakes.
• Another natural force that changes
  landforms is called weathering.
Shaping the Earth’s Surface (cont.)
• During this process, water and ice,
  chemicals, and even plants break rocks
  apart into smaller pieces.
• Forces such as water, wind, and ice can
  move weathered rock in a process called
  erosion.
What is the name of the region
around the edge of the Pacific Ocean
where many volcanoes and
earthquakes occur?
A. Ring of Fire
B. Pangaea                          A.   A
                                    B.   B
C. San Andreas Fault
                              0%    C.
                                   0%    C
                                         0%   0%
D. Plate tectonics        A
                                    D.   D
                                   B




                                         C




                                              D
Geographic factors influence where
people settle.
Content Vocabulary
• continental   • water cycle
  shelf
                • evaporation
• trench
                • condensation
• groundwater
                • precipitation
• aquifer
                • collection
Academic Vocabulary
• occur     • availability
• define
Do you think there are mountains
underwater?
A. Yes
B. No
                                A. A
                                B. B
                            0%     0%

                            A




                                   B
Between June and August 1993, an extraordinary
amount of precipitation fell in the Midwestern United
States. Meteorologists recorded a 200 to 350 percent
increase from the normal rainfall. Floodwaters from the
overflowing Mississippi and Missouri Rivers covered
400,000 square miles (1.04 million sq. km) and 15
million acres of farmland in nine states.
Types of Landforms
          Earth has a variety of
          landforms, and many of the
          landforms can be found both
          on the continents and the
          ocean floors.
Types of Landforms (cont.)
• Mountains, the highest landforms, range
  in height from a few thousand feet to
  nearly 30,000 feet (9144 m).
• Hills are lower and more rounded than
  mountains.
• Other landforms are valleys and flatlands.
• A valley is lower than the land on either
  side and lies between mountains and hills.
Types of Landforms (cont.)
• Flatlands occur in one of two forms.
  – Plains are flat lowlands, typically found
    along coasts and lowland river valleys.
  – Plateaus are flatlands at higher
    elevations.
Types of Landforms (cont.)
• Geographers define some landforms by
  their relationship to bodies of water.
  Examples are an isthmus, a peninsula,
  and an island.
• Off each coast of a continent lies a
  plateau called a continental shelf that
  stretches for several miles underwater.
• Mountains also are found underwater.
Types of Landforms (cont.)
• Tectonic activity makes deep cuts in the
  ocean floor called trenches.
• A well-known trench is the Mariana Trench
  in the western Pacific Ocean.
• Humans settle on all types of landforms.
• Factors that help people decide where to
  live include climate and the availability of
  freshwater and food sources.
Where is the Mariana Trench located?
A. Pacific Ocean
B. Atlantic Ocean
C. Indian Ocean
                                    A.   A
D. Arctic Ocean
                                    B.   B
                              0%    C.
                                   0%    C
                                         0%   0%
                          A
                                    D.   D
                                   B




                                         C




                                              D
The Water Planet
          Water covers much of the
          planet, but only some of this
          water is usable.
The Water Planet (cont.)
• About 70 percent of the Earth’s surface is
  covered with water.
• Almost 97 percent of the Earth’s water is
  salt water.
• Narrow bodies of water called straits or
  channels link seas, bays, and gulfs to the
  oceans.
The Water Planet (cont.)
• Only 3 percent of the water on Earth is
  freshwater.
• Much of this freshwater is frozen in ice that
  covers polar regions and parts of
  mountains.
The Water Planet (cont.)
• Some freshwater is groundwater, which
  filters through the soil into the ground.
• Groundwater often gathers in aquifers, or
  underground layers of rock through which
  water flows.
• Lakes are large inland bodies of water.
The Water Planet (cont.)
• Rivers are long, flowing bodies of water.
• Rivers begin at a source and end at a
  mouth.
• The mouth is the place where a river
  empties into another body of water, such
  as an ocean or a lake.
The Water Planet (cont.)
• The largest rivers often have many
  tributaries, which are separate streams or
  rivers that feed into them.
• Many rivers form deltas at their mouths by
  depositing soil.
  – Here a river breaks into many different
    streams flowing toward the sea.
The Water Planet (cont.)
• The water on Earth moves constantly in a
  process called the water cycle.
• The sun drives the water cycle because it
  evaporates water, turning water from a
  liquid to a gas called water vapor.
• Condensation occurs when cool
  temperatures change water vapor back to
  a liquid.

                        The Water Cycle
The Water Planet (cont.)
• When the liquid form falls to Earth, it is
  called precipitation.
• The cycle is completed when collection
  takes place in rivers, lakes, and oceans.
What percentage of the Earth’s water
is salt water?
A. 10
B. 50
C. 75                               A.   A
D. 97                               B.   B
                              0%    C.
                                   0%    C
                                         0%   0%
                          A
                                    D.   D
                                   B




                                         C




                                              D
Geographers organize the Earth into
regions that share common
characteristics.
Content Vocabulary
• weather        • local wind
• climate        • rain shadow
• prevailing wind • climate zone
• current        • biome
• El Niño        • urban climate
• La Niña
Academic Vocabulary
• distribute   • alter
Is there a specific kind of climate you
usually visit on vacation?
A. Yes
B. No
                                  A. A
                                  B. B
                               0%    0%

                              A




                                      B
Tornadoes usually come one at a time, but now and
then several come at once. What is now known as the
Super Outbreak occurred in April 1974. In a 16-hour
period, scientists counted 148 tornadoes in 13
Midwestern and Southern states. Five large tornadoes
were on the ground at the same time.
Effects on Climate
          Sun, wind, and water
          influence Earth’s climate.
Effects on Climate (cont.)
• Weather refers to the changes in
  temperature, wind direction and speed,
  and air moisture that take place over a
  short period of time.
• Climate is the usual, predictable patterns
  of weather in an area over many years.
• The sun does not heat the Earth evenly.
  The movement of air and water over the
  Earth helps to distribute heat more evenly
  around the planet.
Effects on Climate (cont.)
• Air in the Tropics, which is warmed by the
  sun, moves north and south toward the
  Poles of the Earth.
• Colder air from the Poles moves toward the
  Equator. These movements of air are winds.
• Major wind systems follow patterns that are
  similar over time and are called prevailing
  winds.

                   Prevailing Wind Patterns
Effects on Climate (cont.)
• The winds that blow from east to west
  between the Tropics and the Equator are
  called trade winds.
• The westerlies, which blow over North
  America, move from west to east.
• When moist, warm air rises suddenly and
  meets dry, cold air, major storms can
  develop.
Effects on Climate (cont.)
• These storms in the summer can include
  thunder and lightning, heavy rain, and,
  sometimes, tornadoes.
• Tornadoes are violent, funnel-shaped
  windstorms with wind speeds up to 450
  miles per hour.
• Hurricanes are destructive storms that
  occur in the western Atlantic and eastern
  Pacific Oceans. Typhoons occur in the
  western Pacific Ocean.
Effects on Climate (cont.)
• The steadily flowing streams of water in
  the world’s seas are called currents.
• Like prevailing winds, currents follow
  patterns.
• Every few years, changes in normal wind
  and water patterns in the Pacific Ocean
  alter weather patterns in many parts of
  the world.

                     World Ocean Currents
Effects on Climate (cont.)
• Two sets of conditions, El Niño and
  La Niña, cause heavy rains in some parts
  of the world and droughts in other parts.
On which ocean do typhoons occur?
A. Atlantic Ocean
B. Pacific Ocean
C. Arctic Ocean
                                  A.   A
D. Indian Ocean
                                  B.   B
                            0%    C.
                                 0%    C
                                       0%   0%
                        A
                                  D.   D
                                 B




                                       C




                                            D
Landforms and Climate
          Landforms, especially
          mountains, can affect winds,
          temperature, and rainfall.
Landforms and Climate (cont.)
• The types of landforms and their nearness
  to water influence climate.

• Some landforms cause local winds, or
  wind patterns typical only in a small area.
• Some local winds occur because land
  warms and cools more quickly than water
  does. Local winds also occur near tall
  mountains.
Landforms and Climate (cont.)
• Mountain peaks are cold and have snow
  even in the Tropics because high mountain
  air is thin and cannot hold heat.
• Mountains have an effect—called a rain
  shadow—whereby they block rain from
  reaching interior regions.
Do mountains have an effect on local
winds?
A. Yes
B. No
                                A. A
                                B. B
                             0%    0%

                            A




                                   B
Climate Zones
          The effects of wind, water,
          latitude, and landforms
          combine to create different
          climate zones.
Climate Zones (cont.)
• Many parts of the world, even though they are
  very distant from one another, have similar
  climates.
• This is known as having the same climate
  zone, or similar patterns of temperature,
  precipitation, and vegetation.
• Climate zones include biomes, or areas such
  as rain forest, desert, grassland, and tundra, in
  which particular kinds of plants and animals
  have adapted to particular climates.
Climate Zones (cont.)
• The five major climate zones are tropical,
  dry, midlatitude, high latitude, and
  highland.
• All but the highland zone have several
  subcategories. For example, the tropical
  zone includes the subcategories of tropical
  rain forest and tropical savanna.



                     World Climate Zones
Climate Zones (cont.)
• Large cities show significant climate
  differences from surrounding areas in their
  zone.
• These urban climates have higher
  temperatures due to paved streets and
  stone buildings that soak up and then
  release more of the sun’s heat energy than
  areas covered by plants.
Climate Zones (cont.)
• The different heat patterns in urban
  climates also cause winds to blow into
  cities from several directions instead of the
  prevailing direction experienced in rural
  areas.
• It is possible that cities have more
  precipitation than rural areas, too.
How many major climates zones are
there?
A. 4
B. 5
C. 7                               A.   A
D. 10                              B.   B
                             0%    C.
                                  0%    C
                                        0%   0%
                         A
                                   D.   D
                                  B




                                        C




                                             D
All living things are dependent upon
one another and their surroundings
for survival.
Content Vocabulary
• smog            • conservation
• acid rain       • irrigation
• greenhouse      • pesticide
  effect
                  • ecosystem
• crop rotation
                  • biodiversity
• deforestation
Academic Vocabulary
• layer     • technique
Are you concerned about global
warming?
A. Yes
B. No

                                 A. A
                                 B. B
                            0%      0%

                           A




                                    B
Cattle ranchers in Oregon have a weed called “leafy
spurge” that harms their ranchlands. Instead of
spraying the weed with chemicals called herbicides,
however, the ranchers have begun renting goats to eat
the weeds. This natural alternative looks promising.
The ranchers get rid of the weeds, no poisons are
used, the goat owners have a new source of income,
and the goats are happy.
The Atmosphere
         Human activity can have a
         negative impact on the air.
The Atmosphere (cont.)
• People burn oil, coal, or gas to make
  electricity, power factories, and move
  vehicles. These actions often cause air
  pollution.
• Air pollution takes several forms.
• Some polluting chemicals combine with
  ozone, a form of oxygen, to create smog.
  Smog is a thick haze of smoke and
  chemicals.
The Atmosphere (cont.)
• Chemicals combine with precipitation to
  form acid rain.
• Acid rain kills fish, eats away at the
  surfaces of buildings, and destroys trees.
• Another form of pollution is from human-
  made chemicals, particularly
  chlorofluorocarbons (CFCs), which destroy
  the ozone layer.

                    The Greenhouse Effect
What is air pollution combined with
precipitation called?
A. Smog
B. Acid rain
C. Greenhouse effect                A. A
                                    B. B
                               0%    0%    0%
                                    C. C
                           A




                                    B




                                           C
The Lithosphere
          Some human activity
          damages our environment.
The Lithosphere (cont.)
• The lithosphere is another name for the
  Earth’s crust. It includes all the land above
  and below the oceans.
• Rich topsoil is a vital part of the
  lithosphere.
• Farming, logging, and mining, if not
  managed properly, can have a negative
  effect on topsoil.
The Lithosphere (cont.)
• Farmers can reduce the loss of topsoil.
• One way is through contour plowing, or
  plowing along the curves of the land rather
  than in straight lines. This prevents the soil
  from washing away.
• Another way is crop rotation, or changing
  what is planted from year to year.
• A third way is to plant grasses in empty fields
  to hold the soil in place.
The Lithosphere (cont.)
• Deforestation, or cutting down forests
  without replanting them, is another way
  topsoil is lost.
• When the tree roots are no longer there to
  hold the soil in place, wind and water can
  carry away the soil.
Which has a negative effect on the
lithosphere?
A. Farming
B. Logging
C. Mining                            A.   A
D. All of the above                  B.   B
                               0%
                                     C.
                                    0%
                                          C
                                          0%   0%
                           A




                                    B




                                          C




                                               D
                                     D.   D
The Hydrosphere and Biosphere
          Water pollution poses a threat
          to a vital and limited resource.
The Hydrosphere and Biosphere (cont.)
• The hydrosphere includes the Earth’s
  surface water and groundwater.
• The amount of freshwater on Earth is
  limited, so people should practice
  conservation, or the careful use of a
  resource, to avoid wasting water.
The Hydrosphere and Biosphere (cont.)
• The water supply is harmed in several
  ways.
• The water used in irrigation, a process in
  which water is collected and distributed to
  crops, is often lost through evaporation.
• Pollution from industrial plants and
  pesticides is also harmful.
• Pesticides are powerful chemicals that
  farmers use to kill crop-destroying insects.
The Hydrosphere and Biosphere (cont.)
• The biosphere includes all the plants and
  animals on Earth.
• The biosphere is divided into ecosystems.
• An ecosystem is a place shared by plants
  and animals that depend on one another
  for survival.
• Changes to ecosystems can lead to
  shrinking biodiversity, or the variety of
  plants and animals living on the planet.
What is the process used by farmers
in which water is collected and
distributed to crops?
A. Conservation
B. Irrigation
                                    A.   A
C. Pesticides
                                    B.   B
D. Biodiversity               0%
                                    C.
                                   0%
                                         C
                                         0%   0%
                          A




                                   B




                                         C




                                              D
                                    D.   D
Inside the Earth
• Earth has four layers: the inner and outer
  cores, the mantle, and the crust.
• The continents are on large plates that
  move.
• Plates colliding or pulling apart reshape
  the land.
Shaping Landforms
• Water, chemicals, and plants break rock
  apart into smaller pieces.
• Water, wind, and ice can cause erosion.
Shaping Landforms
• Mountains, plateaus, valleys, and other
  landforms are found on land and under
  oceans.
• Climate and availability of resources affect
  where humans settle.
The Water Planet
• About 70 percent of the Earth’s surface is
  water.
• In a process called the water cycle, water
  travels from the oceans to the air to the
  ground and back to the oceans.
Climate
• Climate is the usual pattern of weather over a
  long period of time.
• Sun, winds, ocean currents, landforms, and
  latitude affect climate.
• Geographers divide the world into different
  climate zones.
Humans and the Environment
• A delicate balance exists among the Earth’s
  atmosphere, lithosphere, hydrosphere, and
  biosphere.
• Human actions, such as burning fuels and
  clearing rain forests, affect the environment.
Answers will vary,
but should refer to
the filtering or
blocking of
ultraviolet radiation.
core
area at the center of the Earth, which
includes a solid inner core and a hot
liquid outer core
mantle
Earth’s thickest layer, found between
the core and the crust
magma
hot melted rock inside the Earth that
flows to the surface when a volcano
erupts
crust
uppermost layer of the Earth
continent
large landmass that rises above an
ocean
plate tectonics
scientific theory that explains how
processes within the Earth form
continents and cause their movement
earthquake
sudden and violent movement of the
Earth’s crust that shakes the land and
can cause great damage
fault
crack in the Earth’s crust where two
tectonic plates meet; prone to
earthquakes
weathering
process in which rock is broken into
smaller pieces by water and ice,
chemicals, or even plants
erosion
process by which weathered bits of
rock are moved elsewhere by water,
wind, or ice
release
to relieve pressure; to set free
constant
happening a lot or all the time
accumulate
to increase in amount
continental shelf
plateau off a continent that lies under
the ocean and stretches for several
miles
trench
deep cut in the ocean floor
groundwater
water that filters through the soil into
the ground
aquifer
underground layer of rock through
which water flows
water cycle
system in which water moves from
the Earth to the air and back to the
Earth
evaporation
part of the water cycle; process by
which water changes from liquid to
gas
condensation
part of the water cycle; process by
which water changes from gas to
liquid
precipitation
part of the water cycle; process by
which water falls to the Earth as, for
example, rain or snow
collection
part of the water cycle; process by
which streams and rivers carry water
that has fallen to the Earth back to the
oceans
occur
to be found in
define
to describe or establish
availability
easy or possible to get or use
weather
changes in temperature, wind speed
and direction, and air moisture that
take place over a short period of time
climate
pattern of weather that takes place in
an area over many years
prevailing wind
wind patterns that are similar over
time
current
steadily flowing stream of water in the
ocean
El Niño
weather phenomenon marked by very
heavy rains in western South
America, often causing flooding;
reduced rainfall in Southern Asia,
Australia, and Africa; and severe
storms in North America (opposite of
La Niña)
La Niña
weather phenomenon marked by
unusually cool waters in the eastern
Pacific and low amounts of rainfall
there and heavier rains—and a
greater chance of typhoons—in the
western Pacific (opposite of El Niño)
local wind
wind pattern typical of a small area
rain shadow
effect of mountains that block rain
from reaching interior regions
climate zone
areas that have similar patterns of
temperature and rainfall and may
have similar vegetation
biome
area that includes particular kinds of
plants and animals adapted to
conditions there
urban climate
weather patterns in cities, including
higher temperatures and distinct wind
patterns, as compared to nearby rural
areas
distribute
to spread out
alter
to change
smog
thick haze of smoke and chemicals
acid rain
chemicals from air pollution that
combine with precipitation
greenhouse effect
buildup of certain gases in the Earth’s
atmosphere that, like a greenhouse,
retain the sun’s warmth
crop rotation
changing what crops farmers plant in
a field from year to year
deforestation
cutting down of forests without
replanting new trees
conservation
careful use of resources to avoid
wasting them
irrigation
process of collecting water and
distributing it to crops
pesticide
powerful chemicals that kill crop-
destroying insects
ecosystem
place shared by plants and animals
that depend on one another for
survival
biodiversity
variety of plants and animals living on
the planet
layer
to form by adding layers
technique
a method of accomplishing something
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