Chapter 2 A Living Planet
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Transcript Chapter 2 A Living Planet
Chapter 2
A Living Planet
The Solar System
Consists of the sun and nine
planets and other celestial
bodies
–Comets: spheres of ice and
dust
–Asteroids: large chunks of
rocky material
The Structure of the Earth
Earth has 3
layers
–Core: iron and
nickel
–Mantle: magma
–Crust: thin
layer of rock
The Structure of the Earth
Atmosphere: layer of gases
Lithosphere: includes crust and upper
mantle
– Forms ocean floor
– Forms 7 continents: Asia, Africa, North
America, South America, Europe,
Australia, Antartica
Hydrosphere: water elements of earth
Biosphere: where plants and animals live
The Structure of the Earth
Continental Drift Theory
–Earth was once a
supercontinent that divided
and slowly drifted apart over
millions of years
Bodies of Water
Oceans and Seas
– Covers 71% of earth
– Pacific Ocean, Atlantic Ocean, Indian Ocean,
Artic Ocean
– Circulates through 3 basic motions
Currents: like rivers in ocean
Waves: swells or ridges produced by wind
Tides: created by gravitational pull of moon
or sun
Bodies of Water
Hydrologic Cycle
–The continuous
circulation of
water between
the atmosphere,
the oceans, and
the earth
Bodies of Water
Lakes
– Hold more than 95% of earth’s fresh
water supply
– Salt water lakes
Rivers and streams
– Flow through channels and move water
to or from larger bodies of water
– Drainage basin: are drained by major
river
Bodies of Water
Ground Water
–Water held in pores of rock
–Water table: level at which rock is
saturated
Can change depending on
amount of precipitation
Landforms
Naturally formed features on the surface of
the earth
– Volcano
– Strait
– Island
– Delta
– Marsh
– Oasis
– Flood plain
– Bay
-Plateau
-Mesa
-Prairie
-Steppe
-Valley
-Canyon
-River mouth
-Harbor
-Cataract
-Glacier
-Cliff
-Mountain
-Butte
-Swamp
-Cape
-Sea level
Landforms
Oceanic landforms:
–Continental shelf: earth’s surface from
edge of a continent to deep part of the
ocean
–Ridges: places where new crust is being
formed on edges of tectonic plates
–Islands: formed by volcanic action,
deposits of sand, or deposits of coral
skeletons
Landforms
Continental landforms
– Relief: the difference in elevation of a
landform from its lowest point to its
highest point
Mountains, hills, plains, plateaus
– Topography: the combination of the
surface shape and composition of the
landforms and their distribution in a
region
Internal Forces Shaping the Earth
Plate tectonics
Earthquakes
Volcanoes
Plate Tectonics
Tectonic Plates: enormous moving pieces of
the earth’s lithosphere
– Move in 1 of 4 ways
Spreading or moving apart
Subduction or diving under another
plate
Collision or crashing into one another
Sliding past each other in a shearing
movement
Plate Tectonics
3 types of boundaries mark plate
movement
– Divergent boundary: move apart
horizontally
– Convergent boundary: plates collide; one
goes under the other or both plates
crumble
– Transform boundary: plates slide past
one another
– Fault: fracture in the earth’s crust
Volcanoes
Crack in earth’s
surface where
magma, gases,
and water from the
lower part of the
mantle pour out
Lava: magma that
has reached
earth’s surface
Volcanoes
Ring of Fire
– Zone around rim of
the Pacific Ocean
– Eight major plates
meet here
– Volcanic action and
earthquakes often
occur
– Hot springs and
geysers
Earthquakes
Violent movement of the earth
Occurs when plates slide past each
other at a fault
Seismograph: detects earthquakes
Earthquakes
Location
– Focus: where earthquake begins
– Epicenter: directly above focus on the
earth’s surface
Damage
– Richter Scale: relative strength of
earthquake
Tsunami
– Giant wave in ocean
External Forces Shaping the Earth
Weathering
Erosion
Building soil
Weathering
Physical and chemical
processes that change the
characteristics of rock on or
near the earth’s surface
Creates sediment; smaller
pieces of rock
–Mud, sand, silt
Weathering
Mechanical weathering:
processes that break rock into
smaller pieces
–Does not change composition
of rock
–Frost, plant roots, human
activity
Weathering
Chemical weathering: rock is
changed into a new substance as a
result of interaction between
elements in the air or water and
minerals in the rock
–Iron rusting, acid rain
–Occurs more in warm, moist
climates
Erosion
Occurs when weathered
material is moved by the action
of wind, water, ice or gravity
Transporting agent must be
present
Erosion
Water erosion
–Water flows in streams or rivers
Erode vertically and horizontally
Delta: fan-like landform that occurs
when a river enters the ocean
–Wave action along coastline
Can reduce or increase beaches
Erosion
Wind erosion
–Transports and deposits material in
other locations
–New landforms may be produced
Sand dunes
–Loess
Wind blown silt and clay sediment
that produce very fertile soil
Erosion
Glacial erosion
–Glacier: large, long-lasting mass of
ice that moves because of gravity
–Glaciation: the changing of
landforms by slowly moving
glaciers
–Moraine: when rocks left behind by
a glacier form a ridge or hill
Building Soil
Soil: loose mixture of weathered rock,
organic matter (humus), air and water
Soil factors
–Parent material
–Relief
–Organisms
–Climate
–Time