Physical geography discusses
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Introduction to Physical Geography
Physical geography explains the spa- tial dimension of Earth’s dynamic sys- tems—its energy, air, water, weather, climate, tectonics, landforms, rocks, soils, ecosystems, and biomes— terms that will become familiar to you as we progress through this book. Physical geography also inves- tigates how humans interact with Earth systems. The discipline’s spatial perspective, allows geographers to examine processes and events hap- pening at specific locations and to follow their effects across the globe. We hope you find Geosystems Core an important physical geography resource as you explore our unique planet and its life-supporting Earth systems. Let the journey begin!
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A small glacial tarn reflects the peaks and glaciers of Canada’s Purcell Mountains.
Key Concepts & Topics
1 What is physical geography?
I.1 The World Around Us I.2 The Science of Geography I.3 Earth Systems
2 How are locations on Earth located, mapped, & divided into time zones?
I.4 Earth Locations & Times I.5 Maps & Cartography
3 What tools do geographers use?
I.6 Modern Geoscience Tools
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I-4 What is physical geography?
by flows of energy and matter—a concept we will expand upon later in this chapter. Physical geography involves the study of Earth’s environ- ments, including the landscapes, seascapes, atmosphere, and ecosystems on which humans depend. In the second decade of the 21st century,
Welcome to Geosystems Core and the study of physical
geography. In this text, we examine the natural processes on Earth that influence our lives—ranging from weather and climate to earthquakes and volcanoes. We also examine the many ways humans interact with these Earth systems. A system is any set of ordered, interrelated compo- nents and their attributes, linked
Key Learning Concepts ▶ Give examples of the kinds of events, processes, and questions that
physical geography investigates.
I.1 The World Around Us
Atacama Desert, Chile
Jalisco, Mexico
Elwha River, Washington Kathmandu, Nepal
Kampong Speu province, Cambodia
▲ I.1 Locations of events shown in Figure I.2
(a) Flowers blooming in the Atacama Desert, Chile
▲ I.2 Events that shape our changing planet Every day, natural disasters and the effects of ordinary human activities, such as building a dam or using fossil fuels as an energy source, can raise questions to which geographers seek the answers.
our natural world is changing, and the scientific study of Earth and its environments is more crucial than ever.
Asking Geographic Questions Consider as examples the following events, each of which raises questions for the study of Earth’s physical geography (▲ Figs. I.1 and I.2). This text provides tools for answering these questions and addressing the underlying issues.
• In 2015, El Niño rains drenched northern Chile’s Atacama Desert, one of the driest places on Earth. The unexpected deluge brought catastrophic flooding. However, all that water brought something else too. Within months, an explosion of wildflowers carpeted the normally barren ground (▲ Fig. I.2a). In some places, the seeds had been dormant in the soil for decades, until this perfect com- bination of rainfall and spring warmth brought them to life. Will climate change bring more frequent blooms in the future?
• In April 2015, a magnitude 7.8 earthquake stuck the Himala- yan nation of Nepal. The earthquake killed more than 9000 people and injured another 23,000 (▲ Fig. I.2b). Why do earthquakes occur in particular locations across the globe? Why do earthquakes of similar magnitude and duration result in thousands of human casualties in one place, but almost none in another place?
• In 2014, the U.S. National Park Service finished dismantling two dams on the Elwha River in Washington—the largest dam removals in the world to date (▶ Fig. I.2c). The project will restore a free-flowing river for fisheries and associated ecosys- tems. How do dams change river environments? Can rivers be restored after dam removal?
(b) Destruction in Nepal from a 2015 earthquake.
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Introduction to Physical Geography I-5
• In 2015, Hurricane Patricia off the west coast of Mexico became the most powerful tropical storm ever measured in the Western Hemisphere (▼ Fig. I.2d). Although maxi- mum winds over the ocean reached an unprecedented 220 kph (200 mph), the storm weakened quickly as it moved over the rugged terrain of central Mexico. Why are monster storms becoming more common, and how do they threaten human life and property?
• Rapidly evolving technologies such as Global Position- ing Systems (GPS), remote sensing (RS), and geographic information systems (GIS)—terms discussed later in this chapter—increase our ability to collect and analyze the data needed to answer geographic questions (▼ Fig. I.2e). The rise of citizen science, volunteered geographic in- formation (VGI), and participatory GIS (PGIS) provide opportunities for people to help monitor Earth’s natural and human properties. Which areas interest you? This book will show you many possibilities.
Asking “Where?” & “Why?” Physical geography asks where and why questions about processes and events that occur at specific locations and then follow their effects across the globe. Why does the environ- ment vary from equator to midlatitudes and between tropical and polar regions? What produces the patterns of wind, weather, and ocean currents? How does solar energy influence the distribution of trees, soils, climates, and human populations? In this book, we explore those questions and more through geography’s unique emphasis on studying factors that affect the distribution of phenomena on Earth.
Climate Change Science & Physical Geography Climate change is now an overriding focus of the study of Earth systems. The past decade experienced the highest air temperatures over land and water in the in- strumental record. In response, the extent of sea ice in the Arctic Ocean continues to decline to record lows. At the same time, melting of the Greenland and Antarctica Ice Sheets is accelerating and sea level is ris- ing. Elsewhere, intense weather events, drought, and flooding continue to increase. In presenting the state of the planet, Geosystems Core surveys climate change evidence and considers its implications. Welcome to an exploration of physical geography and its impact on our daily lives!
What does the study of physical geography involve?
geoCHECK✔
geoQUIZ
1. Pick one of the events described above and, using your own words, list three geographic questions you would like to answer about that event.
2. Based on the examples above, would you say that humans should be considered part of the natural world? Explain your answer.
3. What is some of the evidence for climate change that scientists have observed?
(e) A student in Cambodia uses GPS to mark a location as part of a government-sponsored, land-reform effort.
Hurricane Patricia
(d) Hurricane Patricia approaching the coast of Mexico
(c) Dam removal on the Elwha River, Washington
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I-6 What is physical geography?
physical geography, research now emphasizes human influences on natural systems. For example, physical geographers monitor air pollution, examine the vulnerability of human populations to climate change, study impacts of human activities on forest health and the movement of invasive species, analyze changes in river systems caused by dam removal, and examine the response of glacial ice to changing climate.
Geography’s spatial analysis method unifies the discipline more than does a specific body of knowledge. Geographers employ spatial analysis to examine how Earth’s processes interact through space or over areas, and to analyze the differences and similarities between places. Process, a set of actions that oper- ate in some special order, is also a central concept of geographic analysis. Therefore, physical geography is the spatial analysis of all the physical elements, processes, and systems that make up the environment: energy, air, water, weather, climate, landforms, soils, humans, animals, plants, microorganisms, and Earth itself.
The world around us is constantly changing as the events and processes described in Module I.1 transform Earth’s
physical environment, affecting humans and other living things. One science seeks to provide answers to our ques- tions about these changes: Geography (from geo, “Earth,” and graphein, “to write”) studies the relationships among natural environments, geographic areas, human society, and the interdependence of all of these across Earth. For geographers, “space” is a term with a special meaning: geographic space comprises Earth’s surface, but as described below, also includes much more than that.
Geographic Perspectives As a science, geography approaches the study of Earth from a number of distinctive perspectives:
• emphasis on spatial and locational analysis • concern with human environment–interactions (discussed below) • adoption of an Earth systems perspective to analyze how the physi-
cal, biological, and human components of those systems are inter- connected (discussed in Module I.3)
Given the complexity of Earth systems, it’s not surprising that geography has many subfields. The field’s two main divisions—human geography and physical geography—are discussed below.
Spatial & Locational Analysis The term spatial refers to the nature and character of physical space, its measurement, and the distribu- tion of things within it. Geographers use spatial analysis as a tool to explain distributions and movement across Earth and how these processes interact with human activities.
Maps showing locations and distributions are important tools for conveying geographic data and interpreting spatial relationships. Evolving technologies such as geographic information systems and the Global Positioning System are widely used for scientific applications as millions of people access maps and locational information every day on computers and mobile devices.
Human Geography & Physical Geography Although geography inte- grates content from many disciplines, it splits broadly into two primary subfields: physical geography, which draws on the physical and life sciences, and human geography, which draws on the social and cultural sciences (▶ Fig. I.3). The growing complexity of the human–Earth relationship in the 21st century is shifting the study of geographic processes even far- ther toward the synthesis of physical and human geography. This more balanced and holistic perspective is the thrust of Geosystems Core. Within
Key Learning Concepts ▶ Describe the main perspectives of geography and distinguish physical
geography from human geography. ▶ Discuss the use of scientific methods in geography. ▶ Summarize how human activities and population growth impact the
environment.
I.2 The Science of Geography
H UMAN GEOGRAPHYH UMAN GEOGRAPHY
PH YSICAL GEOGRAPH
YPH YSICAL GEOGRAPH
Y
Astronomy
Geology
Pedolo gy
M et
eo ro
lo g
y
B io
logy
H is
to ri
ca l
g eo
gr ap
hy
Political
geograph y
Social geography
Cultural geography
Ec onomic
ge
ography
Geodesy
Geomorphology geogra
phy
Soils
Cl im
at o
lo g
yB io
g eo
graphy
H is
to ry
Political scien ce
Sociology
Anthropology
Ec onomics
People Geography
Environment
▲ I.3 The scope of geography While physical geography focuses on processes affecting Earth systems, it shares with human geography tools, methods, and important concerns regarding the interactions among Earth’s physical and human systems.
Explain the two main subfields in geographical science.
geoCHECK✔ (a) Scienti�c Method Flow Chart (b) Using the Scienti�c Method Process to Study the Effects of Dust on Mountain Snowpack
Snow pit for collecting dust from snowpack, San Juan Mountains, Colorado, 13 March 2009.
Dust darkens the surface of snowpack in the San Juan Mountains, CO, March 2009.
Real-World Observations • Observe nature, ask questions, collect data • Search for patterns, build conceptual or numerical models
Hypothesis and Predictions • Formulate hypothesis (a logical explanation) • Identify variables; determine data needed and data collection methods
1. Observations Farmers and ranchers in southern Colorado rely on melting snow from the San Juan Mountains. Water managers have determined that the mountain snowpack now melts earlier in the spring, so water is lost before it can be used.
2. Questions and Variables • Are air temperature increases earlier in the spring responsible for more rapid snowmelt? • Do non-temperature factors contribute to the earlier snowmelt?
3. Hypothesis Although the most likely explanation for earlier snowmelt is increasing temperatures, dust churned up by livestock grazing in the lowlands may also promote rapid melting, as dark dust deposited on the white snow surface absorbs heat.
4. Testing • Review monthly temperature data on changes in air temperatures. • Monitor and measure the deposition of dust on the surface of the mountain snowpack.
5. Results The change in daily and seasonal air temperatures was minor. However, scientists did measure signi�cant dust fall that darkened the snowpack, increasing the absorption of solar radiation and causing more snow to evaporate or to melt more quickly.
Experimentation and Measurement • Conduct experiments to test hypothesis
Result Support Hypothesis Results Do Not Support Hypothesis • Reject hypothesis • Return to an earlier step of the processPeer Review
• Communicate �ndings for evaluation by other scientists • Publish scienti�c paper
Scienti�c Theory Development • Hypothesis survives repeated testing • Comprehensive explanation for an observation is widely accepted and supported by research
The dark surface on the snow is caused by a dust layer.
Other dust layers can be seen within snowpack.
Other dust layers can be seen within snowpack.
The Scientific Process The scientific method is the simple, organized steps leading to- ward concrete, objective conclusions about the natural world (▶ Fig. I.4). Scientific inquiry has no single method as scien- tists in different fields approach their problems in different ways. However, the end result must be a conclusion that other
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Introduction to Physical Geography I-7
SCIENTIFIC METHOD
SCIENTIFIC METHOD
6. T
he or
y d
ev el
op m
en t
5. Results
4. Testing
3. H
yp o
th es
is
2. Questions and
variables
1. Observations
▲ I.4 Scientific method continuum Scientists continually adjust the scientific method and formulate new hypotheses based on new observations, questions and results.
scientists can test repeatedly, either reproducing the results reached by other scientists or possibly showing that the results were false.
Using the Scientific Method Scientists who study the environment begin with clues they see in nature, followed by an exploration of the published scientific literature on their topic. Scientists then use questions and observations to form a hypothesis—a tentative explanation for the phenomena observed. Scientists test hypotheses using experimental studies in laboratories or natural settings (▶ Fig. I.5). If the results support the hypothesis, repeated testing and verification may lead to a new theory. A scientific theory is a widely accepted explanation for a phenomenon that is based on evidence and experimentation and has withstood the scrutiny of the scientific community. Reporting research results in journals and books is also part of the scientific method. Science is objective by nature and does not make value judgments. Instead, science provides people and their institutions with objective information on which to base their own value judgments. The ap- plications of science are increasingly important as Earth’s natural systems respond to the impacts of modern civilization.
(a) Scienti�c Method Flow Chart (b) Using the Scienti�c Method Process to Study the Effects of Dust on Mountain Snowpack
Snow pit for collecting dust from snowpack, San Juan Mountains, Colorado, 13 March 2009.
Dust darkens the surface of snowpack in the San Juan Mountains, CO, March 2009.
Real-World Observations • Observe nature, ask questions, collect data • Search for patterns, build conceptual or numerical models
Hypothesis and Predictions • Formulate hypothesis (a logical explanation) • Identify variables; determine data needed and data collection methods
1. Observations Farmers and ranchers in southern Colorado rely on melting snow from the San Juan Mountains. Water managers have determined that the mountain snowpack now melts earlier in the spring, so water is lost before it can be used.
2. Questions and Variables • Are air temperature increases earlier in the spring responsible for more rapid snowmelt? • Do non-temperature factors contribute to the earlier snowmelt?
3. Hypothesis Although the most likely explanation for earlier snowmelt is increasing temperatures, dust churned up by livestock grazing in the lowlands may also promote rapid melting, as dark dust deposited on the white snow surface absorbs heat.
4. Testing • Review monthly temperature data on changes in air temperatures. • Monitor and measure the deposition of dust on the surface of the mountain snowpack.
5. Results The change in daily and seasonal air temperatures was minor. However, scientists did measure signi�cant dust fall that darkened the snowpack, increasing the absorption of solar radiation and causing more snow to evaporate or to melt more quickly.
Experimentation and Measurement • Conduct experiments to test hypothesis
Result Support Hypothesis Results Do Not Support Hypothesis • Reject hypothesis • Return to an earlier step of the processPeer Review
• Communicate �ndings for evaluation by other scientists • Publish scienti�c paper
Scienti�c Theory Development • Hypothesis survives repeated testing • Comprehensive explanation for an observation is widely accepted and supported by research
The dark surface on the snow is caused by a dust layer.
Other dust layers can be seen within snowpack.
Other dust layers can be seen within snowpack.
Compare and contrast a hypothesis and a scientific theory.geoCHECK✔
▲ I.5 Scientific method example application
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I-8 What is physical geography?
Human–Earth Interactions in the 21st Century Throughout, Geosystems Core discusses issues surrounding the per- vasive influence of humans on Earth systems. The global human population passed 7 billion in 2012 and is unevenly distributed among 195 countries. Virtually all population growth is in the less-developed countries that now possess 81% of the total popu- lation (▼ Fig. I.6). We consider the totality of human impact on
I.2 (cont’d) The Science of Geography
Earth to be the human denominator. (Each chapter in your text- book includes a Human Denominator feature that explores hu- man impacts relevant to that chapter.) Just as the denominator in a fraction tells how many parts a whole is divided into, the grow- ing human population and its increasing demand for resources and rising planetary impact suggest the stresses on the whole Earth system that supports us. Yet Earth’s resource base—the numerator in this fraction—remains relatively fixed.
0
1
2
3
4
5
6
7
8
10,000 8,000
Year 6,000 Present2,0004,000
H u
m an
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( b
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n s)
Old Stone Age
Bronze Age
Iron Ages
Middle Ages
New Stone Age
Old Stone Age
Bronze Age
Iron Ages
Middle Ages
New Stone Age
Old Stone Age
Cave art
Hunter-gatherers
Metal working Industrial era
Cave art
Hunter-gatherers Irrigation and
plowing Irrigation and
plowing
Metal working Industrial era
2012 7 billion Bronze
Age Iron Ages
Middle Ages
New Stone Age
1996 6 billion
1959 3 billion
1927 3 billion
(a) Hunter-gatherers depend on wild plants and animals.
(d) Today, farmers can use new technologies to produce foods in arti�cial environments, as in hydroponic farming.
(b) Subsistence farmers use �re to clear the forest before planting crops.
(c) The plow, irrigation, and application of fertilizers enable people to produce more food on the same land year after year.
500,000500,000
▲ I.6 Human population growth Human population remained relatively low for tens of thousands of years. The shift from hunting and gathering to farming, often called the Agricultural Revolution, occurred in several dif- ferent regions beginning about 10,000 years ago. A larger, more stable food supply enabled more people to live together in permanent settlements, pursue specialized occupations, and develop new technologies. Cities grew, em- pires emerged, and population increased at higher rates—especially after the Industrial Revolution of the late 1700s. Humans interact with and impact the environment as we obtain food. Today, people still obtain food in ways that have sustained humanity for thousands of years.
Mobile Field Trip Introduction to
Physical Geography
https://goo.gl/B2xTBh
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Introduction to Physical Geography I-9
Approximately 38% of Earth’s population lives in China and India alone (◀ Fig. I.7). The overall planetary population is young, with 26% still under the age of 25 years. However, people in more developed countries have a greater impact on the planet per person. The United States and Canada, with about 5% of the world’s popula- tion, produce about 25% of the world’s gross domestic product. These two countries use more than 2 times the energy per capita of Europeans, more than 7 times that of Latin Americans, 10 times that of Asians, and 20 times that of Africans. Therefore, the impact of this 5% on the Earth systems and natural resources is enormous.
Many key issues for this century fall beneath the umbrella of geographic sci- ence, such as global food supply, energy demands, climate change, biodiversity loss, and air and water pollution. Addressing these issues in new ways is necessary to achieve sustainability for both human and Earth systems (◀ Fig. I.8). The term sustainability refers to the ability to continue a defined activity over the long term in a way that prevents or minimizes adverse impacts on the environment. Thus physical geography is concerned with environ- mental sustainability measures such as the rates of natural resource harvest, the creation and release of pollutants, and the consumption of nonrenewable re- sources such as coal and copper (which are only sustainable if comparable and renewable substances are developed
in their place). In each of these three categories, activi- ties are not sustainable unless people can prevent or mitigate their environmental impacts. Understanding Earth’s physical geography and geographic science can help to inform your thinking on these issues.
ATLANTIC OCEAN
ARCTIC OCEAN
ATLANTIC OCEAN
INDIAN OCEAN
PACIFIC OCEAN
PACIFIC OCEAN
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160º140º 180º
Equator
Tropic of Capricorn
Tropic of Cancer
0
2000 4000 KILOMETERS0
2000 4000 MILES
ATLANTIC OCEAN
ARCTIC OCEAN
ATLANTIC OCEAN
INDIAN OCEAN
PACIFIC OCEAN
PACIFIC OCEAN
0º20º 20º40º 40º60º80º 80º100º 100º120º 120º140º160º
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Tropic of Cancer
1000 250 25 5 1
POPULATION PER SQ. KM
0
2000 4000 KILOMETERS0
2000 4000 MILES
(a) World population density map
(b) Night lights around the world
▲ I.7 Population density and electric lights
What percent of the world population is under 25 years of age?
geoCHECK✔
geoQUIZ
1. Explain the origin of the term geography. 2. Describe at least two perspectives that geography uses
to study Earth. 3. Identify how much more—or less—energy you might use
living in Latin America, Asia, or Africa.
▼ I.8 Organic farming in Thailand Organic farming is a type of sustainable agriculture that maintains soil fertility.
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I-10
I.3 Earth Systems
The word system is used in our lives daily: “Check
the car’s cooling system” or “A weather system is ap- proaching.” Systems analysis techniques in science began with studies of energy and temperature (thermodynam- ics) in the 19th century. To- day, systems methodology is an important analytical tool.
Systems Theory A system is any set of ordered, interrelated components and their attributes, linked by flows of ener- gy and matter, as distinct from the surrounding environment outside the system. The elements within a system may be arranged in a series or intermingled. A system comprises many interconnected subsystems. Within Earth’s sys- tems, both matter and energy are stored and retrieved, and energy is transformed from one type to another. Matter is mass that assumes a physi- cal shape and occupies space. Energy is a capacity to change the motion and nature of matter.
Earth systems may be open or closed. Open systems are not self-contained in that inputs of energy and matter flow into the system and outputs of energy and matter flow from the system (▲ Fig. I.9). Earth is an open system in terms of energy, because solar energy enters freely and heat energy returns back into space. Within the Earth system, many subsystems interconnect. Free-flowing rivers are open systems where inputs of solar energy, precipita- tion, and soil particles lead to outputs of water and sediments to the ocean. A forest is another example of an open system. The input of solar energy allows trees to absorb and then store sunlight as plant materials. Forests then output oxygen that plants and animals require to survive.
In contrast, a closed system is self-contained and shut off from the surrounding environment. Although rare in nature, Earth itself is a closed system in terms of physical matter and resources—air, water, and natural resources. The only exceptions are the slow escape of lightweight gases from the atmosphere into space and the input of tiny meteors and cosmic dust.
Key Learning Concepts ▶ Describe systems analysis, open and closed systems. ▶ Explain the difference between positive and negative feedback information. ▶ List Earth’s four spheres and classify them as biotic or abiotic.
What is physical geography?
Actions • Plants make sugar and oxygen from water and light
Human–Earth Connections • Managed properly, the forest provides a source a sustainable wood products, habitat for other plants and animals, protects water quality and soil stability.
Outputs • Oxygen
• Sugar
• Shelter for animals
Inputs • Sunlight
• Air
• Water
▲ I.9 Example of a natural open system: a forest
System Feedback As a system operates, it often generates outputs that influence its own operations. These outputs function as “information” that returns to various points in the system via pathways called feedback loops. Feed- back information often forms a chain of cause and effect that can further influence system operations. If the feed- back information discourages change in the system, it is negative feedback. Negative feedback loops are common in nature. For example, when a thriving forest sinks roots deep into the soil, the amount of erosion will decrease as the vegetation absorbs increasing amounts of water, leav- ing less water to transport soil particles downslope.
If feedback information encourages change in the sys- tem, it is positive feedback. Global climate change cre- ates an example of positive feedback as summer sea ice melts in the Arctic. As arctic temperatures rise, summer sea ice and glacial melting accelerate. This causes light- colored snow and sea-ice surfaces, which reflect sunlight
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Introduction to Physical Geography I-11
Explain the difference between an open and closed system in nature.
geoCHECK✔
and so remain cooler, to be replaced by darker-colored open ocean surfaces, which absorb sunlight and become warmer. As a result, the ocean absorbs more solar energy, which raises the temperature, which in turn melts more ice, and so forth (▶ Fig. I.10). This is a positive feedback loop, further enhancing the effects of higher temperatures and warming trends.
System Equilibrium Most systems maintain structure and charac- ter over time. A system that remains balanced over time, in which conditions are constant or recur, is in a steady-state equilibrium. For example, river channels commonly adjust their form in re- sponse to inputs of water and sediment (particles of rock or soil). These inputs may change in amount from year to year, but the channel form represents a stable average—a steady-state condition.
However, a steady-state system may demonstrate a changing trend over time, a condition described as dynamic equilibrium. The same river may become wider as it adjusts to greater inputs of sediment over some time scale, but the overall system will adjust to this new condition and thus maintain a dynamic equilibrium.
Systems in equilibrium tend to remain in equilibrium and resist abrupt change. However, a system may reach a threshold, or tipping point, where it can no longer maintain its character, so it lurches to a new operation- al level. A large flood in a river system may push the river channel to a threshold where it abruptly shifts, carving a new channel. Plant and animal communities also reach thresholds. For example, scientists identify climate change as one factor triggering a sudden de- cline in aspen trees in the southern Rocky Mountains.
Temperatures rise
Ocean absorbs more heat
Reflectivity, or albedo, is altered (ocean
reflects less sunlight)
Sea ice melts, exposing darker ocean surface
Earth Spheres & Systems Organization in Geosystems Core Earth’s surface is a vast area where four immense open systems interact. The three abiotic, or nonliving, systems overlap as the framework for the realm of the biotic, or living, system. The abiotic spheres are the atmosphere (Chapters 1–3), hydrosphere (Chapters 4–7), and lithosphere (Chapters 8–12). The biosphere is the lone biotic sphere, where all living matter on Earth is found. The living matter of Earth and everything with which it interacts is the biosphere (Chapters 13–14). Together, these spheres form a simplified model of Earth systems (▶ Fig. I.11).
From general layout to presentation of specific top- ics, Geosystems Core follows a systems flow. The book’s structure is designed around Earth’s four “spheres.” Within each part, chapters and topics are arranged according to systems thinking, focusing on inputs, ac- tions, and outputs, with an emphasis on human–Earth interactions and on interrelations among the other parts and chapters.
Describe the relationship between Earth spheres and the content organization in Geosystems Core.
geoCHECK✔
geoQUIZ
1. Identify the role a “threshold” plays in an environmental system. 2. Describe an example of a “feedback” loop in nature. 3. Explain the difference between abiotic and biotic systems.
▲ I.10 The Arctic sea ice-albedo positive feedback loop
Atmosphere
Biosphere
Hydrosphere
Lithosphere
▲ I.11 The four major Earth spheres Of these, three are abiotic and one is biotic.
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I-12 How are locations on Earth located, mapped, & divided into time zones?
As geographers study the physical features and processes on Earth’s surface, they need to accurately locate these phe-
nomena in space and time. You have probably noticed the network of lines that crisscrosses most globes and world maps. This “geographic grid” allows us to locate places and regions on Earth. The size and rotational velocity of Earth combine to make a 24-hour day, and Earth’s annual revolution around the Sun determines the length of a year.
Earth’s Dimensions & Shape Humans have known that Earth is round since the first ship sailed over the ho- rizon and viewers on shore saw the top sails disappear last. Our scientific un- derstanding of Earth’s size and shape began slowly, but has grown rapidly over the past 300 years. Over 2000 years ago, the Greek mathematician Pythagoras (ca. 580–500 BCE) determined that Earth is round, or spherical. Eratosthenes (ca. 276 BC –194 BCE) calculated the circumference of Earth in 247 BCE by comparing the angle of the Sun at noon at two different locations (▶ Fig. I.12). By the first century CE, educated people generally accepted the idea of a spheri- cal Earth. In 1687, Sir Isaac Newton reasoned that Earth’s rapid rotation pro- duced an equatorial bulge as centrifugal force pulled Earth’s surface outward. As a result, Earth’s equatorial circumference is 67 km (42 mi) greater than its polar circumference. Earth is indeed slightly misshapen into an oblate spheroid (oblate means “flattened”), with the flatness occurring at the poles.
Today, satellite observations have confirmed with tremendous precision Earth’s equatorial bulge and polar “flatness.” The irregular shape of Earth’s surface, coinciding with mean sea level and perpendicular to the direction of gravity, is called the geoid. Figure I.13 shows Earth’s polar and equatorial circumferences and diameters.
Key Learning Concepts ▶ Summarize progress in geographical knowledge about Earth’s size and shape. ▶ Explain Earth’s reference grid, including latitude and longitude and latitudinal
geographic zones. ▶ Interpret a map of Earth’s time zones.
I.4 Earth Locations & Times
Earth’s Reference Grid Fundamental to geography is an internationally ac- cepted grid coordinate system to determine location. Geographers use pairs of numbers, or “coordinates,” to locate specific points on the grid. Eratosthenes created the first world map with a rectangular grid to locate places around 200 BCE. The use of a geographic grid made it possible to accurately measure distances between locations. The terms latitude and longitude were used on maps in the first century CE to refer to distances measured in relation to standard lines on the grid. These distances are measured in degrees—units based on the division of a perfect circle into 360 equal parts (▶ Fig. I.14).
North Pole
Equator 12,756 km (7926 mi)
South Pole
(7 90
0 m
i) 12
,7 14
k m
Polar circumference 40,008 km (24,860 mi)
Equatorial circumference 40,075 km (24,902 mi)
North Pole
Geoidal bulge
Geoidal bulge
(b) Equatorial and polar diameters(a) Equatorial and polar circumferences
▲ I.13 Earth’s dimensions The dashed line is a perfect circle for comparison to Earth’s geoid.
Why is Earth’s equatorial circumference larger than its polar circumference?
geoCHECK✔
7.2°
15°
15°
30°
30°
7.2°
Center of Earth
Top of wall shadow
45°
60°
75°
Obelisk at Alexandria
(7.2° shadow)
Well at Syene (no shadow)
Sun‘s rays (parallel)
0°
The angle between Alexandria and Syene is 7.2°, or 1/50th of 360°. Therefore, Earth’s circumference is 50 times the distance between Alexandria and Syene.
▲ I.12 Eratosthenes method for calculating Earth’s circumference Although Eratosthenes calculated the circum- ference of Earth over 2000 years ago, his answer, based on scien- tific and mathematical reasoning, was surprisingly accurate.
M00_CHRI4744_01_SE_C00.indd 12 25/01/16 11:07 PM
Introduction to Physical Geography I-13
Latitude The angular distance in degrees north or south of the
equator, measured from the center of Earth is latitude (▶ Fig. I.15a). (The equator is the line that divides the spherical Earth into north- ern and southern hemi- spheres). Lines of latitude
run east-west, parallel to the equator (▶ Fig. I.15b). Lati-
tude increases from the equator at 0° latitude, to the poles, at 90° north and south.
A line of latitude is called a parallel. In Figure I.15b, an angle of 49° is shown, and by
connecting all points at 49° N, we can draw the 49th parallel. When writing the latitude of location, it is not necessary to include the word latitude, since the suffix of N or S indicates that you are giving the lati- tude, giving 40° N is sufficient. Latitude is the name of the angle (49° N), parallel names the line (49th parallel), and both indicate distance north of the equator.
Throughout this book, you will read references to latitudinal zones as a way of generalizing the location of different phenomena, from weather patterns to plant and animal communities. Lower latitudes are toward the equator, higher latitudes are toward the poles. The terms “the tropics” and “the Arctic” refer to environments created by different amounts of solar energy received at different latitudes. Figure I.16 displays the names and locations of the latitudinal geographic zones used by geographers: equatorial and tropical, subtropical, midlatitude, sub- arctic or subantarctic, and arctic or antarctic. These latitudinal zones are useful for reference, but they do not have rigid boundaries. We discuss specific lines of latitude, such as the Tropic of Cancer and the Arctic Circle, in Chapter 1 as we learn about the seasons.
10° 20°
80°
0° 0°
49°
49°
N 70° 60° 50° 40° 30° 20° 10° 0°
North Pole 90°
49th parallel
Parallels Equatorial parallel
North Pole 90°
49th parallel
Angle of latitude
Equatorial plane
(a) Latitude is measured in degrees north or south of the Equator (0°). Earth’s poles are at 90°. Note the measurement of 49° latitude.
(b) These angles of latitude determine parallels along Earth’s surface.
▲ I.15 Parallels of latitude Do you know your present latitude?
Arctic Circle
55°
35°
0°
35°
55°
Tropic of Cancer
Equator
Tropic of Capricorn
Antarctic Circle
Arctic: 66.5°N to North Pole
Antarctic: 66.5°S to South Pole
Subarctic: 55°N to 66.5°N
Subantarctic: 55°S to 66.5°S
Midlatitude: 35°N to 55°N
Midlatitude: 35°S to 55°S
Subtropical: 23.5°N to 35°N
Subtropical: 23.5°S to 35°S
Equatorial and tropical: 23.5°N to 23.5°S
▲ I.16 Latitudinal geographic zones Geographic zones are generalizations that characterize various regions by latitude.
▲ I.14 360° in a circle, with the cardinal directions
270° 90°EW
N
S
NE
SW
NW
SE
45°
0°
315°
135°225°
180°
M00_CHRI4744_01_SE_C00.indd 13 25/01/16 11:07 PM
I-14 How are locations on Earth located, mapped, & divided into time zones?
Longitude The angular distance east or west of a point on Earth’s surface, measured from the center of Earth is longitude (▶ Fig. I.17a). On a map or globe, the lines designating these angles of longitude run north and south (Fig. I.17a). A line connecting all points along the same longi- tude is a meridian. In the figure, a longitudinal angle of 60° is shown. These meridians run at right angles (90°) to all paral- lels. Longitude is the name of the angle, meridian names the line, and both indicate distance in degrees east or west of the prime meridian, designated as 0° (▶ Fig. I.17b). Earth’s prime me- ridian—also called the Greenwich meridian—passes through the old Royal Observatory at Greenwich, England, as set by an 1884 treaty. Because meridians of longitude converge at the poles, the length on the ground of 1° of longitude is greatest at the equator and shrinks to zero at the poles. Longitude increases east and west from 0° at the prime meridian to 180°. Just as with latitude, it is not necessary to include the word longitude when writing a location’s longitude. The suffix E or W indicates longitude.
Figure I.18 combines latitude and parallels with longitude and meridians to illustrate Earth’s complete coordinate grid system. Note the red dot that marks 49° N and 60° E, a location in west- ern Kazakhstan. Next time you look at a world globe, follow the parallel and meridian that converge on your location.
I.4 (cont’d) Earth Locations & Times
60°
180° 120° W
0° W
E
30° W
60° W
30° E
60° E
Greenwich, England (prime meridian)
Angle of longitude
Meridians
0° 60°
E
120° E
150° E
150° W
60° W
90° W
90° E
30° E
East
W est
Lo ng
itu de
3 0°
W
Longitude 60°E
(a) Longitude is measured in degrees east or west of a 0° starting line, the prime meridian. Note the measurement of 60° E longitude.
(b) Angles of longitude measured from the prime meridian determine other meridians. North America is west of Greenwich; therefore, it is in the Western Hemisphere.
▲ I.17 Meridians of longitude Do you know your present longitude?
Which latitudinal zone do you live in? Why aren’t lines of longitude parallel?
geoCHECK✔
Meridians & Global Time A worldwide time system is necessary to coordi- nate international trade, airline schedules, and daily life. Our time system is based on the fact that Earth rotates on its axis, rotating 360° every 24 hours, or 15° per hour (360° ÷ 24 = 15°).
In 1884 at the International Meridian Con- ference in Washington, DC, the prime meridian was set as the official standard for the world time zone system—Greenwich Mean Time (GMT). This standard time system established
24 equally spaced standard meridians around the globe, with a time zone of 1 hour spanning 7.5° on either side of these central merid- ians (▶ Fig. I.19). Before this universal system, time zones were not consistently defined, especially in large countries. In 1870, if you were traveling from Maine to San Francisco by railroad, you would have made 22 adjustments to keep on local time!
As you can see in Figure I.19, national or state boundaries and political considerations can distort time boundaries. For example, China spans four time zones, but its government decided to keep the entire country operating at the same time. Thus, in some parts
of China clocks are several hours off from what the Sun is doing. In the United States, parts of Florida and west
Texas are in the same time zone. In 1972, Coordinated Universal Time (UTC)
replaced GMT as the legal reference for official time in all countries. You might still see official UTC referred to as GMT or Zulu time.
International Date Line On the opposite side of the planet from the prime meridian is the
International Date Line (▶ Fig. I.20), which marks the line where one day officially changes
to another. The International Date Line does not completely coincide with the 180th meridian, but
jogs east or west to avoid dividing countries. If you travel west across the International Date Line, you would immediately gain a day, and if you travel east you immediately lose a day. From this line, the new day moves westward as Earth
▲ I.18 Earth’s coordinate grid system Parallels of latitude and meridians of longitude allow us to locate all places on Earth precisely. The red dot is at 49° N and 60° E.
0°
30° W
60° W
30° E
60° E
90° E
10° 20°
80°
N
S
70°
60°
50°
40°
30°
20°
10° 0°
M00_CHRI4744_01_SE_C00.indd 14 25/01/16 11:07 PM
Introduction to Physical Geography I-15
turns eastward on its axis. At the International Date Line, the west side of the line is always 1 day ahead of the east side of the line. No matter what the time of day when the line is crossed, the calendar changes a day.
Daylight Saving Time In 70 countries, mainly in the midlatitudes, time is set ahead 1 hour in the spring and set behind 1 hour in the fall—a practice known as daylight saving time. The idea to extend daylight for early even- ing activities at the expense of daylight in the morning, first proposed by Benjamin Franklin, was not adopted until World War I and again in World War II to save energy by reducing the use of electric light. In 1986 and again in 2007, the United States and Canada extended the number of weeks of daylight saving time. Currently, time “springs forward” 1 hour on the second Sunday in March and “falls back” 1 hour on the first Sunday in November, except in a few places that do not use daylight saving time (Hawaii, Arizona, and Saskatchewan).
geoQUIZ
1. Compare the geoid with a hypothetical Earth-like planet of the same size that is a perfect sphere. How are they similar? How are they different?
2. Why is it important to have a standard prime meridian? 3. Determine your longitude using an online map or an atlas. How many degrees
are you away from a time zone central meridian (75°, 90°, 105°, 120°, 135°)? Given that Earth rotates through 1° in 4 minutes, how many minutes apart are the Sun and your watch?
Seward
Denver
Mexico City
New York
Rio de Janeiro
Lagos
Cairo
Perth Sydney
Wellington
Singapore
Honolulu
Fairbanks
Chicago
Los Angeles
Vancouver Halifax
Winnipeg
Churchill Edmonton
Resolute Thule
Jerusalem
Rome
Moscow
Tokyo Beijing
Mumbai
Vladivostok
Almaty (Alma Ata)
London (Greenwich)
ALASKA
HAWAII
4:30
12:30 1:30 3:30
12:45
12:30
11:3010:30
3:30 Newfoundland time
12:30 2:30
A la
sk a
Pa ci
fi c
M o
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ta in
C en
tr al
Ea st
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A tl
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12 MIDNIGHT
12 NOON2 A.M. 3 A.M. 4 A.M. 6 A.M. 7 A.M. 8 A.M. 9 A.M. 10 A.M. 11 A.M. 1 P.M. 2 P.M. 3 P.M. 4 P.M. 5 P.M. 6 P.M. 7 P.M. 8 P.M. 9 P.M. 10 P.M. 11 P.M. 12
MIDNIGHT5 A.M.1 A.M.
Pr im
e M
er id
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at e
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Non-standard time
Aleutian Is.
In te
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at e
Li n
e
16 0°
E
14 0°
E
160° W
140° W
120° W
0° Equator
180th meridian
20° N
40° N
60° N
20° S
40° S
60° S
Earth’s
rotation
South Pole
North Pole
Monday Sunday
Add a day
Subtract a day
▲ I.20 International Date Line The International Date Line (IDL) location is approximately along the 180th meridian (see the IDL location on Figure I.19). The dotted lines on the map show where island countries have set their own time zones, but their political control extends only 3.5 nautical miles (4 mi) offshore. Officially, you gain 1 day crossing the IDL from east to west.
How many degrees apart are time zones?geoCHECK✔
▲ I.19 Modern international standard time zones If it is 7 p.m. in Greenwich, determine the present time in Moscow, London, Halifax, Chicago, Winnipeg, Denver, Los Angeles, Fairbanks, Honolulu, Tokyo, and Singapore.
M00_CHRI4744_01_SE_C00.indd 15 25/01/16 11:07 PM
I-16 How are locations on Earth located, mapped, & divided into time zones?
For centuries, geographers have used maps as tools to display information and analyze spatial relationships.
A map is a generalized view of an area, as seen from above and reduced in size. A map usually represents a specific characteristic of a place or area, such as rainfall, airline routes, physical features such as mountains and rivers, or political features such as state boundaries and place names. Cartography is the science and art of mapmaking, often
Key Learning Concepts ▶ List the basic elements of a map. ▶ Explain the three different ways of expressing map scale. ▶ Summarize how and why map projections were developed and how they are used in cartography. ▶ Give examples of the different kinds of maps and how each is used.
I.5 Maps & Cartography
blending geography, mathematics, computer sci- ence, and art.
We all use maps to visualize our location in relation to other places, to plan trips, or to understand a news story or current event. Un- derstanding how to “read” or interpret different kinds of maps is essential to our study of physi- cal geography.
What are the basic map elements?
geoCHECK✔
10
10
5
5
5
110
405
405
710
105
110
2
1
91
134
110
134
101
101
Downtown map area
Inglewood
Beverly Hills
Pasadena Glendale
La Cañada Flintridge
Burbank
El Segundo Compton
Huntington Park
GardenaManhattan Beach
Torrance
Rancho Palos Verdes
Long Beach
LOS ANGELES
Los Angeles Intl. Airport
Griffith Park
Downtown map area
Inglewood
Beverly Hills
Pasadena Glendale
La Cañada Flintridge
Burbank
El Segundo Compton
Huntington Park
GardenaManhattan Beach
Torrance
Rancho Palos Verdes
Long Beach
LOS ANGELES
PACIFIC OCEAN
Los Angeles Intl. Airport
Griffith Park
110
110
10
S. Flo
wer S
t.
S. Fig
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a St
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S. Oliv
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S. Hi
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S. M ain St.
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W. 5th St.W. 6th St. 7th St.
E. 16th St.
E. Washington Blvd.
W. 8th St.
Pico Blvd.
W. 9th St. W. Olympic Blvd.
W. Olympic Blvd.
E. 9th St.
Los Angeles Convention Center
STAPLES Center
Transamerica Center
Los Angeles Trade Technical College
Microsoft Theater Fashion Institute
of Design and Merchandising
L.A. Live
FASHION DISTRICT
DOWNTOWN
LOS ANGELES
W. 8th St.
S. Flo
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t.
S. Fig
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W. 5th St.W. 6th St. 7th St.
E. 16th St.
E. Washington Blvd.
W. 8th St.
W. 8th
Pico Blvd.
W. 9th St. W. Olympic Blvd.
W. Olympic Blvd.
E. 9th St.
St.
Los Angeles Convention Center
STAPLES Center
Transamerica Center
Los Angeles Trade Technical College
Microsoft Theater Fashion Institute
of Design and Merchandising
L.A. Live
FASHION DISTRICT
DOWNTOWN
LOS ANGELES
LOS ANGELES REGION DOWNTOWN LOS ANGELES
Point of interest
Airport
Interstate highway
State highway
Street
110
110
Representative fraction: 1:500,000 or 1/500,000
1 inch = 8 miles 1 cm = 5.0 km
Written scale:
Graphic scale:
Representative fraction: 1:24,000 or 1/24,000
1 inch = 2000 feet 1 cm = 0.25 km
Written scale:
Graphic scale: 0
5 10 KILOMETERS0
4 8 MILES 0
0.25 0.5 KILOMETERS0
1000 2000 FEET
(a) Relatively small scale map of Los Angeles area shows less detail.
(b) Relatively large scale map of the same area shows a higher level of detail.
◀ I.21 Map scale Examples of maps at different scales, with three common expressions of map scale—representative fraction, written scale, and graphic scale. Both maps are enlarged, so only the graphic scale is accurate.
Basic Map Elements Most maps share the same elements:
• title—gives the subject of the map and may also include in- formation about who made the map, the source of map data, and the date when the map was produced
• north arrow—tells the reader which direction is north on the map
• symbols—represent features on the map using lines, patterns, areas of color, icons, and other graphic elements
• legend—tells the map reader what each symbol means
• map scale—states the mathemati- cal relationship between the size of the map and the size of the portion of Earth the map repre- sents (discussed below)
• map projection—enables show- ing the round Earth as a flat map (discussed below)
M00_CHRI4744_01_SE_C00.indd 16 25/01/16 11:07 PM
The Scale of Maps Architects, toy designers, and mapmakers all represent real things and places with models that are smaller than the thing they represent. Examples include the floorplan of a building; a diagram of a toy car, train, or plane; or a map. Each of these models has a particular scale, or relationship between the size of the model and the size of the actual thing it depicts. For example, an architect draws a blueprint for builders so that 0.25 inch on the drawing represents 1 foot on the building.
Cartographers do the same thing in making maps. The ratio of the size of a map to that area in the real world is the map’s scale. Scale can be represented as a ratio (also called representative fraction), a graphic scale, or a written scale (◀ Fig. I.21). For exam- ple, a useful scale for a local map is 1:24,000, a ratio in which 1 unit on the map repre- sents 24,000 units on the ground. Geographers refer to as small-, medium-, or large-scale maps, depending upon the map’s scale. A map with a scale of 1:24,000 is a large-scale map, while a scale of 1:50,000,000 is a small-scale map. The larger the number on the right, the smaller the scale. Small-scale maps have less detail for a larger area, while large-scale maps show more detail for a smaller area (Fig. I.21). Scale is represented as a representative fraction, a graphic scale, or a written scale (Fig. I.21).
Ratio Scale & Representative Fraction A ratio scale, or representative fraction, can be expressed with either a colon (for a ratio) or a slash (for a fraction), as in 1:24,000 or 1/24,000. No actual units of measurement are mentioned because both parts of the fraction are in the same unit: 1 cm to 24,000 cm or 1 in. to 24,000 in.
Graphic Scale A graphic scale, or bar scale, is a graphic with units to allow measure- ment of distances on the map. An advantage of a graphic scale is that if the map is enlarged or reduced, the scale is enlarged or reduced by the same amount, unlike written and fractional scales that become incorrect when map size changes.
Written Scale A written scale usually has differing, but common, units such as 1 inch equals 1 mile. For example, the ratio scale 1:24,000 conveniently converts to “1 inch equals 2000 feet” when expressed as a written scale (by dividing 24,000 by 12 in./ft).
Which map has more detail, a large-scale or small-scale map?geoCHECK✔
Map Projections A globe is a small-scale, three-dimensional representation of Earth. Globes can pro- vide an accurate representation of area and shape on Earth. However, if you wanted to go hiking or explore a new city, you need more information than a globe can pro- vide. To provide more detail, cartographers make large-scale maps, which are two- dimensional representations of Earth. However, converting a three-dimensional sphere to a two-dimensional map causes some degree of distortion of areas and shapes. To control distortion on a flat map, cartographers use a map projection. By manipulating the grid coordinate system that is common to both globes and flat maps, a map projection enables cartographers to transfer data about points and lines on a globe accurately to a flat surface. Centuries ago, cartographers actually projected the shadow of a wire frame globe onto a geometric surface, such as a cylinder, plane, or cone. The wires represented parallels, meridians, and the outlines of continents. Modern cartography uses mathematical formulas to generate the many different kinds of map projections. Some are better at showing shape accurately, while others are better for showing area accurately. Cartographers must decide which characteristic to preserve, which to distort, and how much distortion is acceptable.
If you imagine taking a globe apart and trying to lay it flat on a table, that illus- trates some of the problems with map projections (▶ Fig. I.22). Although large-scale maps have less distortion than small-scale maps, all maps, regardless of the projec- tion used, have some degree of distortion.
Earth
Reduce
Flatten
Globe
Flattened globe
Map projection (Mercator projection–cylindrical)
Fill in spaces (adds distortion)
180° 180°140° 140°100° 100°60° 60°20° 20°0°
0° 20°
40°
60°
20°
40°
60°
80°
80°
▲ I.22 From globe to flat map Conversion of the globe to a flat map projection requires a decision about which properties to preserve and the amount of distortion that is acceptable.
Introduction to Physical Geography I-17
M00_CHRI4744_01_SE_C00.indd 17 25/01/16 11:07 PM
I-18 How are locations on Earth located, mapped, & divided into time zones?
I.5 (cont’d) Maps & Cartography
Equal Area or True Shape? One major decision a cartographer must make when beginning a map involves choosing between projections with the properties of equal area and true shape. Cartographers designed different kinds of equal-area projections so that areas are correct on the map regardless of their latitude and longitude (▼ Fig. I.23a). For example, areas measuring 10° of latitude by 10° of longitude are equal whether they are near the equator or near the poles—although the two areas differ greatly in shape. In contrast, a true-shape projection (also called a conformal projection) can correctly represent the shapes of geographic fea- tures such as coastlines and islands, but the sizes of those features can be greatly distorted (Fig. I.22b). The commonly used Mercator projection seen in Figure I.22a is a true-shape projection. Gerardus Mercator developed the projection in 1569 to simplify navigation. Unfortunately, as we saw in Figure I.23b, Mercator maps present a false view of the size of midlatitude and high-latitude regions.
If a cartographer selects an equal-area projection for a map— for example, to show the distribution of world climates—then the map will sacrifice true shape, especially where areas are stretched along the edges of the map. If a cartographer selects a true-shape projection, such as for a map used for navigation, then the map will sacrifice the property of equal area, and different regions of the map will actually have different scales.
Geosystems Core uses equal-area and compromise map projec- tions. Goode’s homolosine projection is an interrupted equal-area
projection and is excellent for mapping features when breaks in the map over oceans or continents is not a problem. Goode’s homolosine projection is used in Geosystems Core for the world climate map in Chapter 6 (Fig. 6.), the world soil orders map (Fig. 14.8), and the terrestrial biomes map in Chapters 14 (Fig. 14.24).
The text also uses the Robinson projection, designed by Arthur Robinson in 1963. This is a compromise projection that is neither equal area nor true shape, but a compromise between the two. Examples of the Robinson projection in Geosystems Core include the latitudinal geographic zones map (Fig. I.16), the distribution of insolation map and the temperature ranges map in Chapter 2 (Figs. 2.5 and 2.31), the maps of lithospheric plates and volcanoes and earthquakes in Chapter 8 (Figs. 8.15 and 8.21).
The Miller cylindrical projection is another compromise pro- jection used in this text. This projection was first developed by Osborn Miller and presented by The American Geographical Society in 1942. This projection is neither true shape nor true area, but is a compromise that avoids the severe scale distortion of the Mercator. Examples of the Miller cylindrical projection in Geosys- tems Core include the world time zone map in Figure I.19, global temperature maps in Chapter 2 (Figs. 2.29 and 2.30), and the two global pressure maps in Chapter 3 (Figs. 3.9 and 3.10).
Which projection described above would be best for comparing the amounts of rain forest in Latin America, Africa, and Southeast Asia? Explain.
geoCHECK✔
(a) Mercator projection
(b) Equal-area projection (Eckert IV)
▲ I.23 True-shape projections vs. equal-area
Kec
KJdg
Khd
0
0.5 1 KILOMETER0
0.5 1 MILE0
0.5 1 KILOMETER0
0.5 1 MILE
Qal
Qtl
Qti
Qpt
Kec
Khd
Kic
Kid
KJdg
Ks
Jms
Alluvium
Talus
Tioga Till
Pre-Tahoe Till
El Capitan Granite
Half Dome Granodiorite
Granodiorite of Illilouette Creek
Quartz diorite
Diorite and gabbro
Sentinel Granodiorite
Metasedimentary rock
SURFICIAL DEPOSITS
PLUTONIC ROCKS
METAMORPHIC ROCKS
Animation Map Projections
http://goo.gl/3wii0g
M00_CHRI4744_01_SE_C00.indd 18 04/02/16 7:46 PM
Types of Maps There are many kinds of maps for a vast number of purposes. Maps portray everything from Earth’s physical features to political boundaries to the de- mographic and economic data that are important to human geographers. Physical geographers often create physical maps that show information about a physical theme such as elevation or temperature. Physical maps often use isolines, which are lines that represent a given value: Contour lines show elevation, isotherms show temperature, isobars show air pressure. Topographic maps are physical maps that can give us a sense of the terrain, or the lay of the land (▶ Fig. I.24). They use different colors to represent different features, blue for water, black for human-made objects, green for vegetation, brown for contour lines. A contour line connects all points at the same elevation. Contour lines show the slope of the land as well as elevation: widely spaced contour lines indicate gentle slopes, and closely spaced contour lines indicate steep slopes. You can also use contour lines to calculate relief, which is the difference in elevation between two locations. Figure i.24 uses shaded relief, an artistic technique of simulated shadows that conveys a sense of what the landscape looks like. Figure i.25 shows slopes derived from digital elevation models. Other important types of physical maps are geologic maps, which show rock formations and faults (▼ Fig. I.26); weather maps, which show present or future forecasts of weather; and climate maps, which show long term averages of differ- ent weather elements such as temperature or rainfall.
Introduction to Physical Geography I-19
geoQUIZ
1. For viewing maps on a smartphone, which type of map scale would be most helpful? Explain.
2. What are the advantages of a globe over a map? Of a map over a globe?
3. Describe the two main types of distortion in map projections.
4. As a cartographer, you are asked to produce a highly accurate topographic map of the county where you live. Would you choose a large-scale or small-scale for the map? An equal area or true shape projection? Explain your answer.
What are the two main types of maps?geoCHECK✔
▲ I.25 Surface slope map for Yosemite Valley Very steep valley walls (red) are easily distinguished from the nearly flat valley floor (blue).
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▼ I.26 Geologic map of Yosemite Valley and surrounding areas
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I-20
I.6 Modern Geoscience Tools
Geographers use a number of new and evolving technolo- gies to analyze and map Earth—the Global Positioning
System (GPS), remote sensing, and geographic information systems (GIS). GPS uses satellites to provide precise locations. Remote sensing uses satellites, aircraft, and other sensors to provide visual data that enhances our understanding of Earth. GIS is a means for storing and analyzing large amounts of spatial data as separate layers of geographic information.
Global Positioning System Using radio signals from a global network of satellites, the Global Positioning System (GPS) accurately determines location anywhere on or near the surface of Earth. A GPS receiver receives radio signals from the satellites and calculates the distance between the receiver and each satellite. By using signals from at least four satellites, precise locations are possible (▼ Fig. I.27). GPS units also report the time, accurate to 100 billionths of a second, which is used to synchronize communications systems, electrical power grids, and financial networks.
GPS receivers are built into many smartphones and motor vehicles. The GPS is useful for many commercial and scientific applications. GPS receivers have been at- tached to sharks and whales to track them in real time to study their migration patterns. Airlines and shipping companies use GPS to track their vehicles, improving fuel efficiency and on-time performance.
Key Learning Concepts ▶ Explain how geographers use the Global Positioning System, remote
sensing, geographic information systems, and geovisualizations.
What tools do geographers use?
Remote Sensing Technological systems of remote sensing obtain informa- tion about objects without physically touching them. We do remote sensing with our eyes as we scan the environment, sensing the shape, size, and color of objects from a distance. Taking a picture with your phone is another example of remote sensing. Geographers use images captured by satel- lites and airborne sensors. During the last 50 years, satellite imagery has transformed Earth observation. Today, you have free access to high-quality remote-sensing imagery, through services such as Google Maps, that in the past would have been unavailable, extremely expensive, or restricted to government intelligence services. Remote sensing can be divided into passive and active remote-sensing systems.
Passive Remote Sensing Systems of passive remote-sensing record energy radiated from a surface, especially visible light and heat (▼ Fig. I.28). Our eyes are passive remote sensors. Weather satellites are passive remote sensing systems with which you are probably familiar. Beginning in the 1970s, the Landsat series of satellites began recording images of Earth with sensors that captured visible light, as well as other wavelengths useful in studying agriculture, forestry, geology, regional planning, mapping, and global change research. Scientists can observe different phenomena with sensors that detect different wavelengths of energy. This allows them to compare healthy vegetation and distressed vegetation or a find outcroppings of a particular rock formation.
Why are at least three satellites needed to find a location using GPS?
geoCHECK✔
Storm runoff entering ocean
1 GPS satellite #1 finds the location on the surface of a sphere.
2 The intersection of the locations from GPS satellites #1 and #2 gives two locations.
3 GPS satellite #3 finds the correct location.
Satellite #1
Satellite #2
Satellite #3
▼ I.27 Using satellites to determine location through GPS
▼ I.28 Passive remote sensing Image from October 15, 2015, showing muddy stream runoff from heavy rains in South Carolina interacting with ocean currents.
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Introduction to Physical Geography I-21
Today, sites such as Google Maps and Bing Maps show us detailed imagery, often in simulated three-dimensions, of any location in the world. Urthecast (www.urthe- cast.com) is now broadcasting near real-time views of Earth from cameras on the International Space Station.
Active Remote Sensing A system that directs energy at a surface and analyzes the en- ergy returned from the surface is referred to as active remote sensing. Taking pictures with a flash in a darkened room is an example of active remote sensing. Another ex- ample is sonar, which has been used to map the ocean floor. A sonar unit emits bursts of sound and measures their return. Another technology is LIDAR (light and radar), which uses pulses of visible light. LIDAR units can be mounted in aircraft and on cars. LIDAR can differentiate between the first pulses returned, usually off the highest vegetation, and later returns, which are usually from the actual ground surface. This capability allows scientists to measure tree canopy heights or to virtually strip away vegetation to create a three-dimensional model of the surface (▶ Fig. I.29). Archae- ologists have used LIDAR to discover several “lost” ancient cities in Central America. Detailed three-dimensional, LIDAR models of modern cities already exist, and LIDAR models of roads will be critical in the development of self-driving cars (▼ Fig. I.30).
▼ I.30 Comparison of first-return and bare ground images of the Oso landslide, WA
Compare and contrast the two types of remote sensing.geoCHECK✔
▼ I.29 Active remote sensing LIDAR is used to produce canopy or bare ground maps.
(a) LIDAR uses pulses of light to form a 3D image of elevated and ground level objects.
(b) LIDAR mapping of the lost city of Caracol hidden below the rain forest canopy in Central America.
LIDAR survey
Conventional aerial photography cannot
penetrate dense jungle canopies
Market plaza
Residential groups
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(a) First return shows top of vegetation
(b) Bare ground return shows ground under vegetation
Head of Oso slide
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Roads
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I-22
I.6 (cont’d) Modern Geoscience Tools
Geographic Information Systems & Geovisualization Techniques such as remote sensing generate large volumes of spatial data to be stored, processed, and analyzed in useful ways. A powerful tool for manipulating and analyzing this spatial data is a geographic in- formation system (GIS). A GIS is a computer-based data-processing tool that combines spatial data (where is it? what is its latitude/longitude? is it a point? a line? a polygon?) with attribute data (what is it?). In a GIS, spatial data can be organized in layers containing different kinds of data (▶ Fig. I.31). When you ask your phone to find the nearest coffee shop, you are using a GIS, probably without realizing it. A GIS program and a database work together to ask spatial analysis questions such as Where are you? Where are the coffee shops? Which shops are closest to you? How do you get to the nearest coffee shop? GIS systems perform these queries across multiple data layers. In the coffee shop example, three layers are required: one with your location, one with the locations of the coffee shops, and one with the layout of the streets. Figures I.32 and I.33 show examples of GIS analysis used to predict natural hazards and map epidemics.
What tools do geographers use?
High
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Layer: ELEVATION
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▶ I.31 Geographic information system (GIS) Wildfires can change the response of hillsides to rainfall so that even modest rainstorms can result in dangerous flash floods and debris flows. The USGS uses a hazard assessment model that incorpo- rates the shape of hillsides, the amount of land that is heavily burned, the steepness of hill slopes, the clay content of the soil, and the projected amount of rainfall on specific slopes to assess the probability and volume of debris flows in burned areas.
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Introduction to Physical Geography I-23
Geovisualization Geovisualization refers to the display of geographic information, often remote-sensing data combined with other data. Google Maps and Google Earth are two examples of geovisualization programs with which you might be familiar. Geovisualization pro- grams often have limited GIS abili- ties, such as the ability to search for locations and add data layers. Many geovisualization programs allow users to upload their own data sets to combine with other user-generated data and the built- in data from the program.
geoQUIZ
1. Explain at least two ways you have benefited from the GPS. 2. What types of remote-sensing data have you seen today? in the past week? 3. Describe the criteria for a GIS used to find a parcel of land to build a new subdivision using the
following data layers: property parcels, zoning layer, floodplain layer, protected wetlands layer.
Describe the two types of information that a GIS combines.
geoCHECK✔
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▲ I.32 Lahar hazard zones and arrival times for Mt. Hood
▼ I.33 Google Earth used to track the retreat of the Jacobshavn glacier, Greenland
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MAPS IMPACT HUMAN UNDERSTANDING • Maps are much older than photographs. • While maps appear in media and books everywhere, few appreciate the dynamic and vital applications they now offer.
HUMANS USE MAPS TO CHANGE THE WORLD • Today as in the past, maps delineate empires, guide explorers, and inspire travelers to go beyond the next horizon.
ISSUES FOR THE 21ST CENTURY • Mapping of natural and human phenomena such as earthquakes, flooding, food insecurity, and terrorist movements, will play an important role in how governments respond to the challenges each event presents. • Rapidly evolving technological advances in geovizualization, GPS, GIS, and cartography will make geospatial science an essential tool for monitoring and analyzing human-environmental change in the 21st century.
THEhumanDENOMINATOR Maps & Global Change
Maps like this one showing air pollution produced by industrial regions in East Asia help scientists monitor changes in air quality worldwide. This is part of a world map NASA compiled based on satellite-based data on nitrogen dioxide gas, a pollutant that can form ground-level ozone, a component of smog.
New maps portray the current and projected impacts of climate change on plants, water resources, human settlement and economic activity.
Scientists around the world use remotely sensed images to measure and analyze changing vegetation cover, water resources, wildlife migration, advancing urban develop- ment, and scores of other purposes. In this example, remotely sensed images from on NASA’s Terra satellite portray the waters near the Falkland Islands off the coast of southern Argentina awash in greens and blues from concentrated phytoplankton. These microscopic, plant-like organisms grow on the ocean surface, and are the foundation of a thriving ocean food chain.
On Earth Day 2014, NASA broadcast a question on social media: “Where are you on Earth Right Now?” People from 113 different countries, representing every continent, submitted over 50,000 georeferenced images. This participatory mapping created our first global selfie.
Looking Ahead We now embark on a journey through Earth’s four spheres from the atmosphere in Part I, Energy and Earth Systems, to the atmosphere and hydrosphere in part Part II, Water, Weather & Climate Systems. Part III, The Geosphere: Earth’s Interior and Surface, explores the processes that shape Earth’s varied topography. Part IV, The Biosphere, analyzes the structure and function of the ecosystems and soils that sustain Earth’s ecosystems, soils, and biomes.
Chapter 1 begins with the Sun, including seasonal changes in the distribution of its energy flow to Earth.
Each Core chapter ends with a Looking Ahead to act as a bridge from one chapter to the next.
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Chapter Review I-25
3. Which of the following economic activities—gold mining, salmon fishing, burning fossil fuels, and wheat farming—is sustainable? Explain your answer.
I.3 Earth Systems
Describe systems analysis, open and closed systems. Explain the difference between positive and negative feedback information. List Earth’s four spheres and classify them as biotic or abiotic.
• A system is any ordered set of interacting components and their attributes, as distinct from their surrounding environment. Earth is an open system in terms of energy, receiving energy from the Sun, but it is essentially a closed system in terms of matter and physical resources. As a system operates, informa- tion is returned to various points in the operational process via pathways of feedback loops. If the feedback discourages change in the system, it is negative feedback that opposes system changes. If feedback information encourages change in the system, it is positive feedback that encourages system changes. When the rates of inputs and outputs in the system are equal and the amounts of energy and matter in storage within the system are constant (or when they fluctuate around a stable average), the system is in dynamic equilibrium. A threshold, or tipping point, is the moment at which a system can no longer maintain its character and lurches to a new operational level. Four immense open systems powerfully interact at Earth’s sur- face. Three of these are abiotic (nonliving)—the atmosphere, hydrosphere, and lithosphere. The fourth is the biotic (living) biosphere.
4. Identify the main difference between an open system and a closed system.
5. Identify a major difference between the four large systems, or spheres, that comprise Earth. Would life on Earth be possible if one of these four spheres did not exist? Explain your answer.
How are locations on Earth located, mapped, & divided into time zones?
I.4 Determining Earth Locations & Times
Explain Earth’s reference grid: latitude and longitude and latitudinal geographic zones and time.
• Earth’s equatorial circumference is 40,075 km (24,902 mi), while its polar circumference is 40,008 km (24,860 mi). Latitude is the angular distance north or south of the equator. Lines of latitude are called parallels and run east-west. Longi- tude is the angular distance east or west of the prime meridian. Lines of longitude are called meridians, and they converge at the poles. The prime meridian is the basis for our system of global time. There are 24 time zones, each 15° wide, but they are distorted by political boundaries. On the opposite side of the planet from the prime meridian is the International Date
What is physical geography?
I.1 The World Around Us
Give examples of the kinds of events, processes, and questions that physical geography investigates.
• Geography combines disciplines from the physical and life sciences with disciplines from the human and cultural sci- ences to attain a holistic view of Earth. Physical geography explains the spatial dimension of Earth’s dynamic systems—its energy, air, water, weather, climate, tectonics, landforms, rocks, soils, plants, ecosystems, and biomes. It also asks where and why questions about processes and events that occur at spe- cific locations and then follow their effects across the globe. The analysis of process—a set of actions or mechanisms that operate in some special order—is also central to geographic understanding. The science of physical geography is uniquely qualified to synthesize the spatial, environmental, and hu- man aspects of our increasingly complex relationship with our home planet—Earth.
1. On the basis of information in this chapter, define physical geography and review the approach that characterizes the geographic sciences.
I.2 The Science of Geography
Describe the main perspectives of geography and distinguish physical geography from human geography. Discuss the use of scientific methods in geography. Summarize how human activities and population growth impact the environment.
• This spatial viewpoint examines the nature and character of Earth and the distribution of phenomena within it. Physical geography applies spatial analysis to all the physical compo- nents and process systems that make up the environment: energy, air, water, weather, climate, landforms, soils, animals, plants, microorganisms, and Earth itself. Understanding the complex relations between Earth’s physical systems and hu- man society is important to human survival. Hypotheses and theories about the Universe, Earth, and life are developed through the scientific process, which relies on a general series of steps that make up the scientific method. Results and con- clusions from scientific experiments can lead to basic theories as well as applied uses for the general public. Awareness of the human denominator, the role of humans on Earth, has led to physical geography’s increasing emphasis on human– environment interactions. The concept of sustainability—the ability to continue activities indefinitely while minimizing their environmental impacts—and functioning Earth systems, is important to physical geography.
2. Sketch a flow diagram of the scientific process and method, beginning with observations and ending the development of a theory.
Chapter Review
M00_CHRI4744_01_SE_C00.indd 25 25/01/16 11:09 PM
Critical Thinking
I-26 Chapter Review
What tools do geographers use?
I.6 Modern Geoscience Tools
Describe modern geographic tools—the Global Positioning System (GPS), remote sensing, and geographic information systems (GIS). Explain how these tools are used in geographic analysis.
• Geographers use a number of new and evolving technologies to analyze and map Earth—the Global Positioning System (GPS), remote sensing, and geographic information systems. GPS uses radio signals from satellites to accurately determine location anywhere on or near the surface of Earth. Remote sensing refers to obtaining information about objects without physically touching them. Passive remote-sensing systems record energy radiated from a surface, especially visible light and infrared energy. Active remote sensing directs energy at a surface and analyzes the energy returned from the surface. LIDAR (light and radar), is an active remote-sensing technology that uses pulses of visible light, rather than radio waves to create a three-dimen- sional model. A GIS is a computer-based data-processing tool that combines spatial data with attribute data. A GIS program and a database work together to ask spatial analysis questions, often across several layers of data.
11. What is a GPS and how does it assist you in finding location and elevation on Earth?
12. What is remote sensing? What are you viewing when you observe a weather satellite image on TV or in the newspaper? Explain.
13. If you were planning the development of a large tract of land, how would a GIS help you? How might planning and zoning be affected if a portion of the tract in the GIS was a floodplain or prime agricultural land?
Line, which marks the place where each day officially begins. No matter what the time of day when the line is crossed, the calendar changes a day. Seventy countries use daylight sav- ing time, setting clocks 1 hour ahead in the spring and 1 hour behind in the fall.
6. Draw a simple sketch describing Earth’s shape and size.
7. Define latitude and parallel and define longitude and merid- ian using a simple sketch with labels.
8. What and where is the prime meridian? How was the location originally selected? Describe the meridian that is opposite the prime meridian on Earth’s surface.
I.5 Maps & Cartography
Define cartography and mapping basics: map scale and map projections.
• A map is a generalized view of an area, as seen from above and reduced in size. Cartography is the science and art of mapmak- ing, often blending geography, mathematics, computer science, and art. The ratio of the size of a map to that area in the real world is the map’s scale. Scale is represented as a representative fraction, a graphic scale, or a written scale. Graphic scales are used when the map may be enlarged or reduced in size. The basic map elements are a title, the scale, a guide to the map symbols, and a north arrow. Maps can be divided into physi- cal and political maps. Topographic maps are physical maps that can give us a sense of the terrain. Relief is the difference in elevation between two locations. The conversion of a represen- tation of the spherical Earth to a flat map is a map projection. All projections create distortion in size or shape or both.
9. What is map scale? What are three ways it can be shown on a map?
10. Describe the differences between the characteristics of a globe and those of a flat map.
abiotic, p. I-11 biotic, p. I-11 cartography, p. I-16 closed system, p. I-10 Coordinated Universal
Time (UTC) , p. I-14 equilibrium, p. I-11 dynamic equilibrium,
p. I-11 equal area, p. I-18
feedback loop, p. I-10 geographic information
system (GIS), p. I-22 geography, p. I-6 geoid, p. I-12 Global Positioning
System (GPS), p. I-20 human denominator,
p. I-8
International Date Line, p. I-14
latitude, p. I-12 LIDAR, p. I-21 longitude, p. I-12 map, p. I-16 map projection, p. I-17 Mercator projection,
p. I-18 meridian, p. I-14
negative feedback, p. I-10
open system, p. I-10 parallel, p. I-13 physical geography, p. I-6 positive feedback, p. I-10 prime meridian, p. I-14 process, p. I-6 relief, p. I-19 remote sensing, p. I-20
scale, p. I-17 scientific method, p. I-6 scientific theory, p. I-7 spatial, p. I-6 spatial analysis, p. I-6 sustainability, p. I-9 system, p. I-4 threshold, p. I-11 topographic maps, p. I-19 true shape, p. I-18
Key Terms
1. Identify the various latitudinal geography zones that roughly subdivide Earth’s surface. In which zones are a) Los Angeles, b) Moscow, and c) Quito?
2. In general terms, using the scientific method as a guide, how might a physical geographer analyze water pollution in the Great Lakes?
3. What and where is the prime meridian? How was the location originally selected? Describe the meridian that is opposite the prime meridian on Earth’s surface.
4. Summarize how world population growth and environmental sustainability are related.
5. Is cartography an art or a science? Explain your answer.
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Figure RI.1 looks across a valley toward the Karakoram Range in Pakistan. The Indus River flows across the center portion of the image.
1. Identify evidence of each of Earth’s four spheres in the image, and classify each of your examples as biotic or abiotic.
2. Does this picture portray and “open” or “closed” Earth system? Explain your answer.
3. Identify and describe any examples of human influences on this landscape.
Viewing Earth from space is to see the world anew! Open Google Earth, and uncheck (or turn off) all Borders and Labels. On the upper right, there are three tools to navigate around Earth. Place your cursor on each tool to learn how they enable one to Look Around, Move Around, and Zoom. Once you are comfortable with zooming about Earth, take the following journey.
Identify and zoom in on each of the continents: Africa, Europe, Asia, North America, South America, Australia, and Antarctica. Which continent is larger: Africa or South America? Next, select the View menu and scroll down to and check Grid. The geographic grid of latitude and longitude lines will appear. Then trace the following imaginary lines around Earth: Equator, Prime Meridian, Tropic of Cancer, and the Tropic of Capricorn. Then zoom in to North America, and slowly trace a route from San Francisco to New York. Finally, enter your present location in the Search window, click “search,” and then answer the following questions.
1. What are the latitude and longitude of your location? (It’s O.K. to give the answer in whole degrees).
Explore
Visual Analysis
Use Google Earth to explore the geographic grid.
Chapter Review I-27
2. Notice the geographic data displayed across the bottom of the Google Earth screen and how the data change as you move the cursor. What is the elevation of the ground surface? What is your “eye altitude”? What is the scale of your current view of the area?
3. Describe the physical features visible in your view. What effects of human activity can you see in the landscape?
Comparing the Spatial Distribution of World Population • Open: MapMaster in MasteringGeography • Select: World. Next, turn on the Population categories, and select
Population Growth Rates.
1. Which regions of Earth currently have the highest natural rate of population increase, and which areas have the lowest rate of increase?
Interactive Mapping Login to the MasteringGeography Study Area to access MapMaster.
• Next, select Literacy Rate from the Population category.
2. Identify the relationship between literacy and population growth rates Europe and Africa.
Looking for additional review and test prep materials? Visit the Study Area in MasteringGeography™ to enhance your geographic literacy, spatial reasoning skills, and understanding of this chapter’s content by accessing a variety of resources,
including MapMaster™ interactive maps, videos, Mobile Field Trips, Project Condor Quadcopter videos, In the News RSS feeds, flashcards, web links, self-study quizzes, and an eText version of Geosystems Core.
▲ RI.2
▲ RI.1
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Apply You are the newly elected president of the Environment Club. You ran on a platform of increasing campus sustainability and your first step is to evaluate your campus’s student cent- er in terms of sustainability. You will map the student center building and all of its sustain- ability features, or lack thereof, and create a plan to enhance the center’s sustainability.
Objectives • Analyze your campus’s student center in
terms of sustainability. • Evaluate changes that could be made
to the student center to improve its sustainability.
• Create a map, using basic map elements, to portray your campus’s student center and its sustainability features.
Procedure, Part I 1. Using Table GLI.1 as a checklist, make in
inventory of your student center’s sustain- able features, and also note the sustain- ability features it lacks.
2. What other sustainability features could you add to Table GLI.1? Add them to the checklist and note whether your student center has (or lacks) them.
3. What Earth systems do these sustainability efforts and features impact the most? Explain your answer.
Procedure, Part II 4. Before you can map your student center,
there are some mapping decisions to be made. First, what will the scale of your map be? How large is your student center? How much of the area around the student center will you show on your map? Map scale is the ratio of the size of objects on your map to objects on the ground. The size of your map will be dictated by the size of your paper. Your campus may have a detailed downloadable map with building footprints.
5. You’ll also have to decide how to use symbols to represent the sustainability features you’re mapping (Fig. GLI.1). Make a list of the features and their symbols that you can use for your map’s legend.
6. Draw your map of your student center and the sustainability features you’ve selected.
7. What features did you map? Were there new features that you weren’t aware of until you started mapping?
8. What scale is your map? Write the scale as both a representative fraction (such as 1:600) and as a written scale (such as one inch equals fifty feet).
Analyze & Conclude 9. Some campuses have offices of sustain-
ability. If you were going to make a GIS map to give to the office of sustainability, how would you organize the data? Would you group the features by geometry, with one layer for the polygons, another layer for the lines, and a third layer for the point features, or would you group them into thematic layers? Discuss your choice.
10. Were there sustainability features did you expect to find in the student center, but didn’t? Were there features that you were surprised to find?
11. Overall, how sustainable is your student center? What were the most sustainable aspects? The least sustainable? Make a list of changes needed to make the center more sustainable.
12. You want to submit your map as part of a sustainability plan for your campus that will appear in the student newspaper. Write a short summary of the plan’s recommenda- tions to improve the sustainability of your campus. Work with other students in your class to assemble a plan combining every- one’s recommendations and send the class plan to your campus administrator, dean, or student paper.
Human-environment relationships are one of the key themes of geography. One aspect of this relationship is sustainabili- ty, the idea that our impact on Earth’s key systems should be minimized. College campuses across the country are taking action to become more sustainable (Figs. GLI.2 and GLI.3). Table GLI.1 lists aspects of sustainability that are relevant to your college campus. In general, buildings are more sustainable if they use less energy and water and if they produce less pollution and solid waste than buildings not designed or modified for sustainability (Fig. GLI.2).
The process of becoming more sustainable often begins with an inventory of existing conditions. In this exercise you will evaluate how sustainable your campus is by mapping sustainable features of your student center.
Mapping for Sustainability: How Eco-Friendly is Your Campus?
GeoLabIntro
GeoLab Intro Pre-Lab Video
https://goo.gl/zH6kIy
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Geosystems Core: GeoLabIntro I-29
▲ GLI.2 Energy efficiency Solar panels on the roof Yale’s School of Forestry and Environmental Studies at Kroon Hall make this building a model of sustainable practices.
Table GLI.1 Sustainability Inventory Energy • Solar photovoltaic panels? • Other renewables? wind turbines? solar hot water?
Buildings & Facilities • Is the building Leadership in Energy and Environmental Design (LEED) certified? • Sustainable materials such as hemp or sustainably harvest forest products? • Waterless urinals? • I nnovative architecture such as straw bale, or windows and overhangs that block summer
sun but let in winter sun? • How energy efficient is the building’s heating and cooling system?
Food (I f the center serves food) • Organic food? • Is the food sourced from local farms?
Transportation • Public transportation: Where are the closest bus stops, light rail stops, or other public
transportation facilities? • Where are the bike racks? How many bicycles can they hold? • Where is the Electronic Vehicle (EV) parking? • Is there special parking for carpools? • Other transportation features such as horse or ski parking?
Waste Reduction • Where are the recycling containers? • Are there compost containers in dining facility? • Is there composting by food services? • Are the paper towels recycled paper? • Are the paper napkins recycled paper?
Water • Where are the water bottle stations? • Does the landscaping outside use drought resistant, native vegetation? • If your campus is in an arid region, is the landscaping water saving?
▲ GLI.1 Symbols of sustainability (Clockwise from top left): transportation (bicycle and electric vehicle); recycling; public transportation; and energy-efficient lighting.
▲ GLI.3 Sustainable transportation Over 50 percent of students at the University of California, Davis travel to campus using a bike or skateboard.
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