physical geography
TRANSCRIPT
WORLD GEOGRAPHYAn Introduction
The Earth in Space Obvious Facts- third planet from sun in
our solar system, layer of air surrounding earth called atmosphere (shields planet from harm), earth rotates on axis (one complete spin 24 hours), complete orbit around sun every 365.25 days (to make up extra days we have leap year)
Earth tilted on axis 23.5 degrees, seasons change as earth revolves around sun, sunlight falls directly on earth in different places as it revolves around sun (direct rays= summer, indirect rays= winter)
Earth in Space Beginning of seasons June 21- sun directly over Tropic of
Cancer (north of equator) summer solstice
December 22- sun directly over Tropic of Capricorn (south of equator) winter solstice
March 21 and September 23 – sun directly over equator, vernal and autumnal equinoxes
Forces that Shape the Earth Earth constantly changing and being reformed Forces beneath the earth- plate tectonics theory used to explain earths
structure Plates sit on top of liquid rock and often move in different directions Theory of plate movement known as continental drift When plates meet it causes earthquakes, push together to form mountains,
when two plates slide next to each other it forms fault lines
Forces that Shape the Earth To identify physical
characteristics of the Earth geographers study landforms (individual features, mountains, valleys)
Once land is formed through plate tectonics it is further shaped by weathering and erosion
Weathering breaks surface rock down eventually into soil
Water, frost, plants, chemicals Erosion- process of wearing
away or removing weathered material
Rivers cause erosion carry away soil
Water, wind and ice weather material (rivers, glaciers)
Landforms and Waterways Mountains, hills, plateaus, plains, valleys,
canyons What makes them different? Elevation
(height above sea level) Plains- low lying areas of flat or gently
rolling land Plateaus- higher elevation, some have
steep cliffs, some flat areas surrounded by mountains
Valleys- lie between mountains and hills Canyon- cut through plateaus cut by
rivers
Other Landforms Some landforms defined
by their relationship with water or larger land areas
Isthmus- narrow piece of land that connects two larger pieces of land
Peninsula- surrounded by water on three sides
Bodies of Water Strait- narrow
bodies of water between two pieces of land
Wider passage of land called a channel
Mouth of river where it flows into larger body of water called a delta
Landforms in the Ocean Continental shelf- off the coast of each
continent Plateau underwater, drops off steeply into deep ocean
Tall mountains and deep valleys under ocean (deep valleys called trench)
Deepest part of ocean called Mariana Trench in Pacific Ocean (over 35,000 feet)
Earth’s Water 70% of Earth’s surface is
water Can’t drink most of it (only
3%) Ocean’s largest bodies of
water (97% of all water) Bays, seas, gulfs- smaller
bodies of water (66 named) Total amount of water on
earth does not change, water is constantly moving (water cycle)
Sun drives water cycle
Earth’s Water Only 3% of water on earth is freshwater and most of that is not
available, most is frozen or trapped underground and held in aquifers Groundwater lies beneath earth’s surface Comes from rain, melted snow Wells and springs tap groundwater Many aquifers are drying up because of heavy human use, water
becomes degraded Efforts being made to make saltwater potable, process is expensive,
not energy efficient
Climates of the Earth
Weather and Climate Weather- day to day changes over a short period of time Climate- usual predictable pattern over a long period of
time What causes climates to vary? Originally the sun, also
latitude, winds, ocean currents, landforms and humans Latitude and Climate- part of earth-sun relationship Tropics- between 23.5 degrees north and south of the
equator sun’s rays hit directly on the earth Sun’s rays not as direct further south and north from this
area Latitude north or south creates climates that follows general
patterns Elevation influences climate Higher altitude has thinner, drier air that holds less heat
ClimateWind and ClimateSun heats up surface of planet unevenly air moves across planet in typical
prevailing patterns, distributes suns heat across planet
Warm air near the equator moves toward poles, cold air from the poles moves toward equator
Air moves from areas of high pressure to low pressure
Earth rotates causes winds to curve Northern hemisphere winds blow
clockwise, Southern Hemisphere blow counterclockwise known as the Coriolis Effect
Monsoon- wind pattern blows over South Asia- dry in the winter and wet in the summer months
ClimateWind and Climate• Hurricanes- extreme tropical
storms formed by seasonal winds blowing off coast of Africa that effect the western hemisphere
• El Nino and La Nina- combination of temperature, wind and water changes in the Pacific off the coast of South America
• El Nino-Pacific warms, more water evaporates, more clouds form, this changes wind and rain patterns in eastern Pacific
• La Nina- water cools and it has effect on western Pacific
Climate Ocean Currents- streams of water carried
across the globe Like wind warm water flows from near equator to
cooler regions Cold water goes from the poles to warmer areas Currents effect climate of areas- Gulf Stream has
effect on Western Europe Gulf Stream starts in Gulf of Mexico, moves
across the Atlantic toward Europe Wind blows across the warm water and
moderates climate of Western Europe
Climate Landforms and Climate Coasts moderated by
oceans, less changeable weather
Land effects climate, creates local winds
Mountains effect rainfall, temperature
Cooler air can’t hold as much moisture, warm moist air falls on windward side of mountain range, as it passes over the mountains the other side (leeward) is dry called the rain shadow effect
Climate Temperatures higher in
cities Absorb more of the sun’s
rays and cools off slower Called urban heat island
effect Greenhouse effect-
burning of fossil fuels releases gasses prevent heat from releasing into atmosphere (controversial)
Clearing rainforests- burning forests releases gasses into air, trees hold moisture less water will evaporate and less rainfall occurs
Climate Zones and Vegetation
Tropical Climates- 23.5 degrees north and south of equator, warm weather
Tropical Rain Forest- 100” of rain per year, lush vegetation, thick forests
Tropical Savanna- wet/dry seasons, has broad grasslands called savannas
Climate Zones and VegetationMidlatitude Climates- 23-
60 degrees north and south of equator
Most of the worlds people live here
Most varied region Results from mixture of
air masses Marine West Coast
Climate- winds from oceans, winters rainy and mild, variety of vegetation
Mediterranean Climate- mild, rainy winters, hot, dry summers. Vegetation shrubs and short trees
Climate Zones and Vegetation
Humid Conintential Climate- winters long, cold, snowy, short hot summers. Vegitation vast grasslands
Humid Subtropical Climate- rain all year, hot, humid summers, winters short and mild
Climate Zones and Vegetation
High Latitude Climates
• 60 degrees north/south to the poles, generally cold
• Subarctic Climate- low population density, huge evergreen forests called taiga
• Tundra Climate- vast treeless plains, harsh and dry. Lower layers of soil permanently frozen (permafrost). In summer soil turns marshy. Few trees, grass and shrubs
Climate Zones and Vegetation
High Latitude Climates Ice Cap Climate- bitterly
cold, lichens and moss only vegetation
Dry Climates Little rainfall, hot days,
cool nights (can also have cold winters) can be found at any latitude
Desert Climate- less than 10” of rain per yr., scattered scrub plants
Steppe Climate- partially dry grasslands, bushes, short grasses cover this zone
Highland Climate Found in all climate zones Timberline- elevation where trees do not
grow
Environmental Balance Humans have settled on all types of landforms Climate, availability of food, water, resources cause people to settle in particular areas Four parts of earth’s physical geography, humans can have a huge effect on these
systems Atmosphere, lithosphere, hydrosphere, biosphere Atmosphere can be effected by humans through pollution Example- Acid Rain, pollutants combine with precipitation. It can destroy forests,
buildings
Environmental Balance Lithosphere Earth’s hard outer shell,
land areas Topsoil- vital part, if not
managed can be eroded and degraded quickly
Deforestation- cutting down trees, another way topsoil can be lost
How can humans protect topsoil?
Environmental Balance Hydrosphere- Limited supply Water Management- conservation most
effective technique Irrigation for crops wasteful, most water
evaporates Chemicals, pesticides, industrial
processes degrade and pollute water supplies
Environmental Balance Biosphere- increase in human population
encroaches on ecosystems, reduces biodiversity
THE HUMAN WORLDPopulation, Culture, Political and Economic Systems, Resources, Trade and the Environment
World Population 6.2 b people on earth Until Industrial
Revolution world’s population grew slowly
Birthrate growing faster than death rate
Natural increase difference between birthrate and death rate
Why population rates vary Improved healthcare, advanced
technology, better nutrition lower death rate
In industrialized countries this accompanied by low birthrate
Some countries have reached zero population growth
Developing world (Latin America, Africa, Asia) birthrate high Large families (cultural feelings)
Population Growth
Challenges of Population Growth Food Supply Use resources
quickly Can technology
keep up?
Negative Population Growth
Death Rate exceeds birth rate
Late 1900’s in Europe Difficult to keep
economy going- fewer workers
Import laborers causes tension between groups
Population Distrbution Human settlement is uneven Less than one- third of planet
inhabited Most live near water, fertile soil and
climate that makes life sustainable Asia 60% of worlds population Europe, N.A. most live in urban areas
Population Density Determine how crowded a country is by
how many live in a square mile or kilometer of land
Why is this not accurate?
Population Movement
Migration movement from one place to another (urban to rural areas, country to country)
Why? push and pull factors
Population moving to urban areas
Reasons- jobs, opportunity
War, environmental disaster, famine cause forced migration
Global Cultures Culture- way of life shared by a group of
people Includes: Language Religion Subgroups Government Economics
Language
Communicate information, share and pass on tradition, values
Unifies culture Worlds languages divided into language groups,
groups with similar roots
Religion Vary greatly around world Unify people, provides sense of identity Influences daily life- morals, values,
holidays Religious symbols, stories shaped
literature, arts
World Religions
Social Groups Allow cultures to work together to meet
basic needs Family most important part of all
cultures, definition and makeup varies Social class- rank based on wealth,
ancestry, education, other criteria Some include diverse ethnic groups
(share common language, history, etc.)
Government Government reflects culture All maintain order, protection from
outside forces, supply services to people Organized by levels of power (national,
state, local) Type of authority- single leader, small
group of leaders, representative leaders
Economic Activity How cultures utilize resources How cultures produce, obtain, use and
sell goods and services
Culture Regions Divided into culture regions that share certain traits Economic systems, forms of government, social groups,
language Share common history, art forms, religion
Cultural Change What creates cultural
change? Within- lifestyles, ideas,
inventions Outside influences- trade,
movement of people and war
Process of spreading new knowledge and skills from one culture to another cultural diffusion
Agricultural Revolution 10, 000 years ago
people first settled in river valleys, established permanent settlements
Shift from gathering food to producing food agricultural revolution
3500 B.C. organized, city based societies with government, trade, art, science established (civilizations)
Culture Hearths First civilizations in areas called cultural hearths All emerged in areas with mild climate, fertile land and
were located near a major river or source of water Factors allowed people to grow surplus food
Specialization and Civilization Surplus food allowed development of
other economic activities and trade Increased wealth, formed complex
governments and societies Governments coordinated building
projects, harvests and military defense Creation of writing systems to record
and transmit information
Cultural ContactsCauses of Change Contact between civilizations through trade
and travel Permanent migration Forced migration (slaves) Favorable conditions (climate, opportunity,
freedom) draw people from one region to another
Cause tradition, practices, beliefs to blend across cultures
Industrial and Information Revolution Industrial Revolution- 1750’s
changes in production b/c of mechanization led to economic, social change
People left farms for jobs, working and living conditions improved
End of 1900’s Information/ Technology Revolution links cultures across globe
Political and Economic Systems Territory, population, sovereignty,
freedom from outside control managed by governments
Make and enforce laws that bind people together
Governments reflect historic, cultural characteristics of each country
Most have different levels of government
RED indicates populistic system BLUE indicates democratic system. ORANGE indicates that political system of the country is now changing from populistic to democratic.
http://www.geocities.com/historymech/maps2.html WHITE means "not enough data to determine political system". GREEN indicates occupied countries (also "not enough data" to determine political system). Yellow dots mark countries that probably could become democratic in next few years.
Government SystemsUnitary System Gives all power to a central government Usually small, not ethnically diverse United Kingdom, France
Federal System Power divided between states and central
government Each has sovereignty in certain areas U.S., Canada, Brazil, Australia, India
Types of Government Three major groups Autocracy- oldest most
common form of government
Achieve authority by inheritance, use of force
Types- totalitarian (single leader) controls all aspects of life, monarchy (king, queen) leadership inherited, have supreme power of government
Constitutional monarchy- monarch share power with elected legislatures
Types of Government Oligarchy- small
group holds power Power from wealth,
military power, social position (sometimes religion)
Control decisions made by elected legislatures, give appearance of representing people
Usually suppress all political opposition
Types of Government Democracy- leaders rule with consent of citizens Citizens have ultimate power Representative democracy- elect people to make laws,
conduct government (legislature) Republic- all major officials elected, head of state
elected for certain term
Economic SystemsThree Basic Decisions What and how many goods and services should
be produced How they should be produced Who gets the goods and services produced
Three types of economic systems1) Traditional 2) Market 3) Command
Economic SystemsTraditional Economy Habit and custom define activity Not free to make decisions, do what was
done in the past Not many left
Economic SystemsMarket Economy (Capitalism) Individuals, private groups makes decisions Based on free enterprise (make what people will
buy) Free enterprise based on right to make a profit
w/o gov’t interference People decide where to work Mixed economy- gov’t supports and regulates
free enterprise, keep competition free and fair Gov’t influences economies by spending United States is an example
Economic SystemsCommand Economy Gov’t owns means of production- land,
labor, capital Directs all economic activity Belief that it is good for society Citizens have no say in how money is
spent by gov’t
Resources, Trade and the Environment
Natural Resources Two types- renewable,
nonrenewable Nonrenewable resources
– minerals, fossil fuels Need to be conserved Renewable resources-
hydroelectric power, solar energy, nuclear energy
Can be expensive, possible environmental consequences
Economic Development Uneven distribution of resources affects
global economy Some countries develop economies
based on their natural resources World Economic Activities divided into
four types Primary, Secondary, Tertiary, Quaternary
Economic Development Primary Economic Activity- taking
and using natural resources, primary economic activity takes place near natural resources
Secondary Economic Activity- adds value to raw materials (manufacturing), activity occurs close to markets
Tertiary Activity- professional, wholesale or retail activities
Quaternary Activity- processing, management and distribution of information (white collar professionals)
Economic Development Developed Countries- mfg., service industries
employ most people Commercial farming, don’t need as many people
to grow food High standard of living
Economic Development Developing
Countries Development is
based on how well a nation provides food, education, shelter, and levels of economic production
Economic Development Developing Countries- mainly in Africa, Asia,
Latin America Working toward manufacturing, mostly
agricultural Subsistence farming Most people poor
Economic Development Characteristics of Developing
Countries1. Low per capita GDP2. Low energy usage, because no
infrastructure or manufacturing3. Most of population in agriculture
(subsistence farming)4. Unemployment rates high5. Education system inadequate,
children needed to work on farms; literacy rates low
6. Most of population is rural (not always)
7. Poor diet, access to health care lead to high infant mortality and lower life expectancy
8. Physical geography makes development difficult
9. Uneven distributions of resources, arable land
Economic DevelopmentPolitical Factors of developing countriesColonial legacy Many were former colonies with economies based on
extraction of raw materials Raw materials shipped to colonizers, turned into finished
products, rely on colonies for manufactured goods After WWII many became independent, turned to central planning
(command economy), many are now turning to free enterpriseCorruption in government Policies and political decisions to only benefit a small
minority, leaving many with needs unmet Civil wars and social unrest have plagued many countries Military leaders spend huge sums of money at the expense of
other societal needs
Economic Development Wealth in developed world leads to
resentment Militant groups form to strike back and
heighten influence to promote change (terrorists)
World Trade Unequal distribution of resources causes
global trade networks to develop Multinational companies (MNC’s)
stimulate trade Based in developed countries, set up
assembly operations in smaller countries to keep down labor costs, sell to developed countries
World TradeBarriers to Trade Countries mange trade to
benefit them Set up restrictions on goods
from other countries (tariffs, quotas, embargoes)
Recent movement to free trade (removal of trade barriers)
Regions join together to remove restrictions (NAFTA, European Union)
People and the Environment Human economic activity has affected
environment Water, air, land pollution Deforestation Expansion of human communities
threatens natural ecosystems (desertification is an example)
Need for more resources to support growing population and technology leads to degradation of environment