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The average yearly conditions of temperature and
precipitation in a region
 Why do the leaves of plants change color and fall in
the autumn?
 What is hibernation and why do some animals engage
in it? What types of animals, generally, hibernate?
 Weather is the daily condition of Earth’s atmosphere at
a particular place and time.
 Climate is the average yearly conditions of temperature
and precipitation in a region.
 Climate is caused by:
 Trapping of heat in the atmosphere
 Latitude
 Transport of heat by winds and ocean currents
 Amount of precipitation
 Shape and elevation of landmasses
 The greenhouse gases are
atmospheric gases that
trap infrared radiation
(heat energy) that has
been reflected off the
Earth’s surface thus
maintaining Earth’s
temperature range.
 The natural event in
which heat is retained by
this layer of greenhouse
gases is called the
greenhouse effect.
Sunlight
Some heat
escapes
into space
Greenhouse
gases trap
some heat
Atmosphere
Earth’s Surface
 Could we survive without the greenhouse effect?
 No, Earth would be too cold for many organisms to
survive, including human beings.
 Can you name any greenhouse gases?
 Think about cycles of matter…
 Water Vapor – evaporation (water cycle)
 Carbon Dioxide (CO2) – burning fossil fuels,
deforestation, volcanic eruptions
 Methane (CH4) – decomposition/decay, livestock waste
 Nitrous Oxide (N2O) – fertilizer, fossil fuels,
denitrification
 Synthetic gases (e.g. CFCs) – industrial processes
 Earth is a sphere tilted on it axis.
 Therefore, solar radiation strikes different parts of
Earth at an angle that varies throughout the year. This
leads to the seasons we have here.
 The equator receives nearly direct sunlight all year.
 The polar regions receive sunlight at a lower angle.
 The three main climate regions of the earth are:
 Tropical
 Temperate
 Polar
Sunlight
90°N North Pole
Arctic Circle
Sunlight
Most direct sunlight
66.5°N
Polar
Temperate
Tropic of Cancer
Equator
Tropic of Capricorn
23.5°N
0°
Tropical
23.5°S
Sunlight
Temperate
Antarctic Circle
Sunlight
66.5°S
90°S South Pole
Polar
 Unequal heating of Earth’s surface drives winds and
ocean currents, which transport heat throughout the
biosphere.
 Warm air over the equator rises, while cooler air over the
poles sinks toward the ground.
 The upward and downward movement of air creates air
currents, or winds, that move heat throughout the
atmosphere.
WINDS
66.5°N
Easterlies
Westerlies
Northeast Trade Winds
23.5°N
0°
Polar
Equator
Southeast Trade Winds
Westerlies
23.5°S
66.5°S
Polar
Easterlies
Prevailing
winds
 Similar patterns of heating and cooling occur in Earth’s
oceans. Cold water near the poles sinks, then flows
parallel to the ocean bottom, and rises in warmer
regions.
 Water is also moved at the surface by winds.
 Movement of the water creates ocean currents, which
transport heat energy throughout the biosphere.
 Surface ocean currents warm or cool the air above
them, affecting the weather and climate of nearby
landmasses.
OCEAN CURRENTS
66.5°N
23.5°N
0°
Equator
23.5°S
66.5°S
Warm currents
Cold currents
 Remember from our last class that carbon dioxide is
released from a variety of sources. A major contributor
to atmospheric CO2 is human activity.
 Levels of CO2 in the atmosphere have risen
dramatically sense the advent of the industrial
revolution.
 Why do you think this is the case?
 In 1850, just before the industrial revolution the [CO2]
in the atmosphere is estimated at about 274 ppm.
 In 2005, the [CO2] in the atmosphere was over 370
ppm, an increase of over 25%.
 What do you think are some potential effects of
increased CO2 in the atmosphere?
 Some potential effects of increased [CO2] could be:
 Increased growth/productivity by vegetation (increased
levels of photosynthesis). Why? (Hint: last class)
 C3 plants (rice, wheat, soybeans) are more limited by
CO2 availability than C4 plants (sugarcane, corn) so C3
plants may spread into C4 areas.
 A link between increased CO2 and increased
temperature exists. So when [CO2] rises, temperature
rises. Why? (Hint: this class)
 What are some potential results, globally and locally,
from rising temperatures?
 The Holocene Extinction is the present, widespread,
ongoing extinction during the current Holocene
Epoch.
 This is the Sixth Great Extinction, the largest since the
one that killed off the last of the terrestrial dinosaurs.
 The Holocene Extinction has been going on since
about 11,000 BCE and has been attributed to
anthropogenic causes by a majority of biologists.
 Human-induced climate change, overexploitation,
deforestation, and the introduction of non-native
species may have all played a role.
 Because all species are interdependent upon one




another, what is the potential impact of losing any one
species?
The brazil nut, the tree from which the name of the
edible nut is derived, is one of the most massive and
important trees in the Amazon.
Only one creature, a rodent called the Agouti, can
crack the shell, thus allowing the tree to reproduce.
Video: http://www.arkive.org/brazil-nuttree/bertholletia-excelsa/video-11.html
Video:
http://www.youtube.com/watch?v=HURyGlOksR0
 There are literally thousands of examples of species’
interdependence.
 Many flowers have evolved to be dependent upon
insects for pollination.
 Can you think of an example?
 The Holocene Extinction is generally thought to have
begun with the extinction of the megafauna at the end
of the last Ice Age.
 Many of these species were hunted to extinction, while
others lost their sources of food due to human
overexploitation.
 The Wooly mammoth
(Mammuthus
primigenius)
 The theory of its
extinction is
controversial.
 Most scientists
believe it was due to
climate change,
overhunting, or a
combination of the
two.
 The Saber-
toothed Cat
(Smilodon
populator)
 Extinction causes
thought to be
similar to
mammoth’s.
 Likely due to
overhunting by
humans.
 Baiji (Lipotes
vexillifer)
 Freshwater river
dolphin from China
 ‘Effectively Extinct’
2006
 Caused by humans:
pollution in rivers,
habitat destruction
(dams), fishing,
collisions with
boats.
 Javan Tiger
(Panthera tigris
sondaica)
 Subspecies of tiger
on Indonesian
island of Java.
 Extinct in 1980s due
to hunting and
habitat destruction.
 If trends continue, what species will most likely
survive? Why?
 If trends continue, what species will most likely go
extinct? Why?
 How is this related to global climate change?
 1. The Earth’s polar regions remain cold because




A. they are never heated by the sun.
B. the sun’s rays are at a very low angle at the poles.
C. the greenhouse effect does not occur at the poles.
D. heat is transported from the poles to the equator.
 2. Earth’s temperature range is maintained by




A. ocean currents and wind.
B. latitude differences.
C. the greenhouse effect.
D. climate zones.
 3. The Holocene Extinction




A. is when the dinosaurs died.
B. led to the Cambrian Explosion.
C. resulted from photosynthesis evolution.
D. is occurring right now.