Download Ch 2-Earth as a System

Ch 2-Earth as a System
• Objectives
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Describe size and shape of Earth
Describe layers of Earth’s interior
Identify possible source of Earth’s magnetic field
Summarize Newton’s law of gravitation
List characteristics of Earth’s 4 major spheres
Identify main sources of energy on Earth
Identify the 4 cycles of matter and energy
Identify the factors that control balance of ecosystem
Summarize how energy is transferred through
ecosystem
– Describe how ecosystems respond to environmental
change
Characteristics of Earth
• Only planet w/ liquid water on surface and
w/ oxygen in atmosphere
• 3rd planet from sun, 4.6 billion yrs old,
made mostly of rock
• Oblate spheroid-slightly flattened sphere
• Pole to pole circumference=40,007 km.
Equatorial circumference=40,074 km
Compositional and structural layers
of Earth’s interior
• How many compositional zones are there?
How many major structural zones are
there?
– How do scientists know this?
– Seismic waves-vibrations that travel through
Earth
• Compositional
– Crust-thin, solid outermost zone of Earth, 1%
of Earth’s mass
• Continental and oceanic crust
• Mantle-beneath crust, 2,900 km thick, 2/3rd of
Earth’s mass
• Core-center of Earth, sphere w/ radius of 3500
km, composed mainly of iron and nickel
• Structural zones
– Lithosphere-uppermost part of mantle and crust, cool
and brittle
– Asthenosphere-less rigid layer, 200-250 km thick,
solid rock has ability to flow-plasticity
– Mesosphere-solid mantle rock
– Outer core-dense liquid
– Inner core-dense, rigid solid, core makes up 1/3 of
Earth’s mass
Earth’s Interior
Compositional Zones
Structural Zones
Earth’s magnetic field
• Earth has 2 magnetic poles, North
geomagnetic pole and south, magnetic
field believed to be liquid iron in outer core
– Motions produce electric currents that create
Earth’s magnetic field
• Sun and moon have magnetic field, no
iron or liquid outer core
Newton’s Law of Gravitation
• Earth is affected by gravity-force of
attraction that exists between
• Who discovered law of gravitation?
• The larger the masses of 2 obj and closer
together the obj are, the greater the force
of gravity between the obj will be
Sec 2: Energy in Earth System
• Matter-anything that has mass, takes up space
• What are subatomic particles?
– Protons, electrons, neutrons, atoms or molecules
• How can energy be transferred?
– Heat, light, vibrations, electromagnetic waves
• Closed system- system in which energy but not
matter is exchanged with the surroundings
• Open System- system in which both energy and
matter are exchanged with the surroundings
Characteristics of Earth’s major
spheres
• Hydrosphere-97% water is salty, 3%
freshwater
– Where do we find freshwater?
– All water except atmosphere
• Atmosphere-blanket of gases that
surrounds earth’s surface. Provides air
and protects against rays.
– What makes up the atmosphere?
• Geosphere-mostly
solid part of Earth,
rock and soil on
continents and ocean
• Biosphere-composed
of all of the forms of
life in geosphere,
hydrosphere,
atmosphere
– Contains any organic
matter not
decomposed
Main sources of energy
• Internal source-used to be radioactive decay,
hot materials move toward surface, cooler
denser materials sink
– Convection
• External source-sun, solar radiation
– What does solar radiation cause?
• 1st law of thermodynamics
– Energy is transferred between systems, cannot be
created nor destroyed
• 2nd law of thermodynamics
– When energy is transferred, matter becomes less
organized w/ time, energy is spread out over time
• How is matter and energy exchanged?
Processes in which matter and
energy cycle on Earth
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Nitrogen cycle
Carbon cycle
Phosphorus cycle
Water cycle
All natural cycles can be altered by human
activities. Give examples
Carbon Cycle
Nitrogen Cycle
Water Cycle
Phosphorus Cycle
Sec 3-Ecology
• What is ecology?
– Study of relationships between living things
and non living things in environment
• What is an ecosystem?
– Community of organisms and the environment
that the organisms inhabit
• What do you find in an ecosystem?
What factors control the balance of
an ecosystem
• Carrying capacity-largest population that
an environment can support at any given
time
• What is earth’s? What happens if
something happens to something in
ecosystem?
• What is ultimate source of energy?
Energy transferred through
ecosystem
• Energy is continually being exchange
through different processes.
– Producers, consumers, sec consumers
• Food Chain-organisms eat more than one
specie. Food web-used to represent
relationships between multiple food chains
How ecosystems respond to
environmental change
• Overconsumption of resources
• Converting large natural areas to
agriculture or urban areas
• Pollution