 Earth’s Systems
and Cycles
Examine Earth from a new
perspective
 http://www.classzone.com/books/
earth_science/terc/content/
visualizations/es0101/es0101page01.
Earth as a System
 A system is a part of the universe that can be
studied separately.
 Scientists sometimes study individual parts of
the Earth such as:
 How mountains form
 Classification of life forms
 How tornadoes form
Today we understand that the all parts of the
Earth are connected and interacting
The best way to understand the Earth is not to
study the parts in isolation but as one system
Closed vs. Open Systems
Closed Systems
Open Systems
Matters does not enter or
leave
Matter enters and leaves
Energy enters and leaves
Energy enters and leaves
Earth is a Closed System
Energy from the sun is
absorbed by the Earth’s
atmosphere and surface
during the day
Energy is lost back into
space at night
The matter on Earth is the
same matter that was
here when Earth
formed.
Matter changes form but
the amount of matter
remains the same
Mt Etna lava picture source: :http://earthobservatory.nasa.gov/Newsroom/NewImages/
images.php3?img_id=17479
.
How is a jar of sun tea
like the Earth?
 Sun tea is made
with tea bags and
water in a closed jar
that is left out in the
sun.
 How is this similar to
Earth as a closed
system?
Except….
What happens when a meteorite hits Earth?
A tiny amount of Hydrogen atoms are lost to space.
Overall, Earth is still considered a closed
system.
This means our resources must be conserved
and protected.
Earth’s system includes 4
spheres that interact
  The Atmosphere consists of the gases that surround the Earth
  The Geosphere (also called lithosphere) consist of the rocks,
minerals, soils, ocean basins and Earth’s interior
  The Hydrosphere includes the water in oceans, rivers,
groundwater, clouds, lakes, ice caps and glaciers
  The Biosphere includes all things living or coming from living
things.
  Visualize Earth’s spheres:
http://www.classzone.com/books/earth_science/terc/content/
visualizations/es0102/es0102page01.cfm?
chapter_no=visualization
Earth’s Sphere’s Interact
 An erupting volcano
releases lava, volcanic
bombs (geosphere) and
gases and ash into the
air (atmosphere), the
animals are suffocated
(biosphere), plants burn
up (biosphere), ash
flows fill rivers
(hydrosphere).
http://volcano.und.edu/vwintl/vwintl.html
More interaction examples
 Plants and animals take
in oxygen from the
atmosphere and release
carbon dioxide.
 People remove plants,
release chemicals into
the air and water
 How does using cars
show interactions
between spheres?
Car exhaust. © NMM London
Cycles involve interactions
between the spheres
A cycle is a event or
process that repeats
over and over again.
Examples:
The water cycle
The carbon cycle
The nitrogen cycle
A biogeochemical cycle
moves nutrients
between living and
nonliving portions of the
Earth
http://www.windows.ucar.edu/tour/link=/earth/Water/co2_cycle.html&edu=mid
The Water Cycle
  Water leaves the oceans and
other bodies of water
through evaporation and
the leaves of plants through
transpiration.
  Solar energy powers this
part of the water cycle.
  Water vapor cools and
condenses to make cloud
droplets or ice crystals that
merge to form rain and other
forms of precipitation.
  Gravity pulls the
precipitation back down to
the surface.
See U.S.G.S for a quick summary:
http://ga.water.usgs.gov/edu/
watercyclesummary.html
Precipitation can be rain,
snow, sleet or hail
 Precipitation falls to
the Earth
 and either infiltrates
into the ground,
 becomes runoff that
moves across the
surface,
 lands in a body of water
  or is evaporated back
up into the sky
 Can you label A - G?
Rita Haberlin’s Lecture notes:
http://members.aol.com/rhaberlin/hcpptnts.htm
We Impact
the Water Cycle
Developing land reduces the
amount of water that can sink
into the ground, infiltration
and increases the amount of
runoff that occurs.
This causes other problems such
as:
Soil erosion
Loss of ground water recharge
Flooding
Pollution of lakes and streams
Judith Earl slideshow:
http://managingwholes.com/photos/erosion/pictures/slide17.html
The Carbon Cycle
  Carbon is the basic element
found in all living organisms
  Carbon is also found:
  in rocks (carbonates) and
shelled organisms
  dissolved in water (carbon
dioxide and carbonic acid
  in the atmosphere (carbon
dioxide)
Windows to the Universe: The Carbon cycle:
http://www.windows.ucar.edu/tour/link=/earth/Water/co2_cycle.html&edu=high
The Carbon Cycle continued
  Plants take in carbon dioxide
from the atmosphere to
make sugars in
photosynthesis
  Animals get their carbon by
eating plants or through food
chains
  Plants, animals and some
bacteria absorb oxygen and
release carbon dioxide
through respiration
  Death and decay of
organisms releases carbon
into the soil
Humans and the Carbon Cycle
  Fossil fuels such as coal
forms when peat moss and
other dead organisms are
buried deep within the earth
for millions of years
  We burn the fossil fuels
through the process of
combustion and release
the stored carbon as carbon
dioxide into the atmosphere
again.
  Scientists are concerned that
increased carbon dioxide
levels in our atmosphere is
causing global warming. http://www.windows.ucar.edu/tour/link=/earth/climate/cli_gallery.html&edu
The Nitrogen Cycle
  Nitrogen is the most
abundant gas in our
atmosphere (78%)
  Nitrogen is an essential plant
nutrient
 As is phosphorus and
potassium
  Bacteria convert nitrogen to
nitrates and ammonia which
plants can absorb from the
soil
  Animals get the nitrogen
they need to build proteins
and other important
molecules by eating plants or
other animals
http://www.windows.ucar.edu/tour/link=/earth/Life/nitrogen_cycle.html
The Nitrogen Cycle continued
 There are also bacteria
that release Nitrogen
gas into the air
 Manure from animals,
human sewage and
chemical fertilizers all
add nitrogen to the soil
and water
 Excess nitrogen in
water causes algae
blooms and can lead to
the premature aging
and death of a lake due
to lack of oxygen
Phytoplankton blooms create a dead zone in the Gulf of Mexico:
http://www.windows.ucar.edu/tour/link=/earth/climate/
nitrogen_fertilizer.html
Energy
 The primary source of energy for the Earth is the sun
 Energy cannot be created or destroyed in ordinary
reactions, only changed from one form to another.
(First Law of Thermodynamics)
 Exceptions to this law are nuclear reactions, fission
and fusion
 Nuclear reactions do create large amounts of
energy from small amounts of matter
 Example - solar power is created through the
fusion (combining) of 4 hydrogen atoms into 1
helium atom
Examples of the energy
changing forms
 Food chains are examples of energy changing form
 Solar energy is trapped by pigments in plants
 This is converted to chemical energy stored in the bonds
of sugars
 Animals that eat the plants obtain chemical energy
 Chemical energy stored in gasoline is released in your car
through combustion
 This turns to mechanical energy to allow your car to
move
  Another way to state this law is
 You can’t make something from nothing
 We cannot create energy
Energy changing form
http://www.ftexploring.com/energy/energy-1.htm
Second Law of
Thermodynamics
 When energy changes
form, it becomes less
and less useful.
 Most of it is lost as heat
 In other words, you
can’t make something
from nothing…
 You can’t even break
even
http://www.ftexploring.com/energy/2nd_Law.html