Transcript Chapter 2 Physical Geography: A Living Planet

Chapter 2
Physical Geography: A
Living Planet
CONTINENTAL DRIFT THEORY
• Originally suggested by Francis Bacon in
1620
• Presented theory in 1912 by Alfred
Wegner of Germany
• Theory states that all continents were
once a super continent that divided and
slowly drifted apart
Where are we?
• 93,000,000 miles from the Sun
• 3rd Planet in from the Sun
• 24,900 miles in circumference and 7900 miles
in diameter
• Only planet in Milky Way solar system that can
sustain human life
THE MILKY
WAY
•
•
•
•
Our Solar system consist of the sun
8 planets
1 dwarf planet (Pluto)
Other celestial bodies that orbit the sun
– Comets > spheres covered with ice and dust that
leave trails of vapor as they race through space
– Asteroids > large chunks of rocky material found
in space
• By size: Pluto (dwarf), Mercury, Mars, Venus,
Earth, Neptune, Uranus, Saturn, Jupiter
Section 1: The Earth
Inside and Out
• 1. The earth is the
only living planet…
• Continents –
landmasses above
water on earth
• 2. The earth
consists of
plates
that float…
• 3. The theory
of continental
drift explains
the formation
of continents
Inside the Earth
Core
– center of the earth
(inner core- liquid iron
and nickel; outer core
– solid iron and
nickel)
Mantle
– several layers
surrounding the core
Crust
– thin layer of rock at
the earth’s surface
Biosphere
• The part of the earth
where plants and
animals live
(atmosphere, lithosphere
and hydrosphere)
On and Above the Earth
• Atmosphere –
layer of gases surrounding
the earth (contains oxygen,
protects the earth from
radiation and space debris,
and provides a medium for
weather and climate
Lithosphere
• Solid rock portion of the
earth (includes crust and
uppermost mantle, ocean
floor, etc.)
Hydrosphere
• Made up of water
elements of the earth
(oceans, seas, rivers,
lakes and water in the
atmosphere)
Section 2: Bodies of
Water and Landforms
• Human Perspective
– The earth is unlike any other
observable planet in our solar
system. It is a living planet.
– Where there is water there is
LIFE.
Section 2: Bodies of
Water and Landforms
The ocean is
interconnected and
covers over 70% of
the earth.
Divided into 4 main
parts. Pacific
(largest), Atlantic,
Arctic and Indian
Ocean Movements
• Currents- like rivers flowing through the ocean
• Waves- swells produced by winds
• Tides - regular rises and falls of the ocean
created by the gravitational pull of the moon or
the sun
MOTION OF THE OCEAN
• The ocean distributes heat.
• Winds blow over the ocean and are
either heated or cooled by the water,
moderating the temperature of the air
over the land.
Hydrologic (water) Cycle
• The water on
earth is
continuously
circulated
between the
atmosphere,
the oceans,
and the earth
LAKES, RIVERS, & STREAMS
• Lakes hold more than 95% of all fresh
water on earth.
• Rivers and streams
move water to or from
larger bodies of water.
LAKES, RIVERS, & STREAMS
• Saltwater lakes are
created when creeks
& rivers carry salts
into a lake, and there
is no outlet to carry
the salt away.
Largest: Caspian Sea (West
Asia)
• Drainage Basin Area drained by a major river and
its tributaries
Ground Water–
water held in the pores of rocks
Water Table –
the rim level at which rocks are
saturated
Oceanic Landforms (topography)
• The ocean floor
and the
continents have
a continental
shelf and slope
• The ocean floor
is similar to the
land above
water.
continental shelf
Continental Shelf
• Earth’s surface from the
edge of a continent to the
deep part of the ocean
Continental Landforms
• Naturally formed features on
the surface of the earth are
landforms
Topography & Relief
• Relief refers to the difference in elevation of a
landform from lowest to highest point
– Mountains, hills, plains, canyons
• The combination of the surface shape and
composition of the landforms and their
distribution in a region > topography
• Topographic Maps show the landforms with their
vertical dimensions and their relationship to
other landforms.
Section 3: Internal Forces
Shaping the Earth
• The earth’s crust
consists of number of
tectonic plates
• tectonic plates enormous moving pieces
of the earth’s lithosphere
– Spreading; subduction;
collision; sliding past each
other in a shearing motion
Movement
of the plates
produces
earthquakes
and volcanoes
• Fault – fracture in the earth’s
crust where plates move past
each other
Types of boundary movements:
• Divergent – plates move apart, spreading
horizontally (i.e. Saudi Arabia & Egypt
making Red sea wider)
Types of boundary movements:
• Convergent – Plates collide, causing either one
plate to dive under the other or the edges of
both plates to crumple (i.e. South Asia
forming the Himalayas)
Types of boundary movements:
• Transform – plates slide past each other (i.e.
San Andreas Fault in California)
Volcanoes – crack in the
earth’s surface where magma
and gases pour out
Benefits > fertile soil &
energy
Lava –
magma that has
reached the earth’s
surface
• Earthquake – Violent movement of the
earth as the plates grind or slip past each
other at a fault
– 95% around Pacific Rim (Ring of Fire)
• Along plate boundaries
• Seismograph –
measures the size of the waves created by
and earthquake
–
Largest Earthquake measured> Kermadec Island, 8.9
Epicenter
• Point directly above the focus
of an earthquake on the
earth’s surface
• Richter Scale –
uses information collected by
seismographs to determine
the strength of an earthquake
DAMAGE
• Landslides
• Fires
• Collapsed Buildings
• Tsunami (speeds up to 450
mph and waves 100 feet tall)
Tsunami
• A giant wave in the
ocean caused by an
underground earthquake
The Ring of Fire
• The most
active
volcano and
earthquake
zone on
earth
“Hot Spots”
• Volcanoes that are far from
the margins of the tectonic
plates are located on “Hot
Spots”.
• Hot springs & geysers are
other features that indicate
areas where the crust is thin.
External Forces Shaping the
Earth
Human Perspective:
In Egypt, a seasonal dry wind is called
Khamsin (50) for the number of days the
season occurs. These wind-driven
sandstorms cause serious problem for
the people of the region.
External Forces Shaping the
Earth
• Weathering and erosion alter the
surface of the earth
• Weathering – physical and
chemical processes that
change the characteristics of
rock on or near the earth’s
surface
• Sediment – Small pieces of rock created
by weathering (mud, sand or silt)
• Mechanical Weathering –
processes that break rock into smaller
pieces (doesn’t change the composition of
rock, but the size)
Example: road construction
- 4 causes > human activity,
plants, frost, ice crystal in
cracks of rocks
• Chemical Weathering –
occurs when rock is changed into a
new substance as a result of
interaction between elements in the
air or water and minerals
• (example – iron rusting)
Erosion
• Occurs when weathered
material is moved by the
action of wind, water, ice and
gravity
Water Erosion
• The motion picks up loose
material and moves it
downstream
• Delta –
sediment is deposited in a fan-like
landform when a river enters an
ocean
Wind erosion
• Wind speeds have to reach 11
mph before fine sediments can be
moved.
• Depending on the types of wind,
different types of landforms can
be formed:
–Loess, sand dunes, rock structures.
wind erosion
Loess –
windblown silt
and clay
sediment that
produces very
fertile soil
Glacial Erosion
• Glacier - a large, longlasting mass of ice that
moves because of gravity
(Form in mountainous regions)
• Glaciation –
changing of landforms by
slowly moving glaciers
• Moraine –
rocks left behind from a
glacier that form a ridge
or hill
BUILDING SOIL
HUMUS Organic material in the soil.
Esker > snakelike ridge
Created by melted ice
Kettle > depression in the ground created by
blocks of trapped ice in the sediment that
melts. They can fill with water to form
lakes.
• Weathering and erosion help form soil. Soil
consist of a loose mixture of weathered rock,
organic matter, air, and water that supports
plant growth
• Factors that determine
soil fertility:
– Parent Material
– Relief
– Organisms
– Climate
– Time
• The variety – and the climates in
which they are found – determine
the types of vegetation that can
grow in a location. Agricultural
activities, such as farming,
ranching, and herding, depend on
this complex relationship.