Transcript Chapter 6

Chapter 6
Climate, Biomes, and Terrestrial
Biodiversity
What is weather?
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Short-term properties of the troposphere
Troposphere: inner layer of the atmosphere
(most of the Earth’s air)
Temperature
Pressure
Humidity
Precipitation
Sunshine
Cloud cover
Warm Fronts
►
Warm air meets and rises up over a retreating
mass of more dense cool air
Cold Fronts
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Cold air moves under a mass of less dense warm
air
Weather Extremes
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Tornadoes (form over land)
- funnel-shaped clouds (vortexes)
- US is most tornado-prone country
Tropical cyclones (form over warm ocean
waters)
- Hurricane (forms in Atlantic Ocean)
- Typhoon (forms in Pacific Ocean)
Figure 6-3
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Descending
cool air
Severe
thunderstorm
Tornado forms when
cool downdraft and
warm updraft of air
meet and interact
Rising
warm air
Severe thunderstorms
can trigger a number
of smaller tornadoes
Rising
updraft
of air
Figure 6-4
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Rising winds exit
from the storm at
high altitudes.
The calm central
eye usually is about
24 kilometers
(15 miles) wide.
.
Moist surface winds
spiral in towards the
center of the storm
Prince William
Sound
Gulf of Alaska
Risk of Tornadoes
CANADA
Highest
High
Medium
UNITED STATES
Low
Tropical Cyclone
Frequency
High
Moderately
high
MEXICO
Atlantic
Ocean
What is Climate?
►
Region’s general pattern of weather
conditions over a long period
►
2 main factors that determine climate:
1. Temperature
2. Average precipitation
Climate
© 2004 Brooks/Cole – Thomson Learning
the average weather patterns for an area over
a long period of time (30 - 1,000,000 years).
It is determined by
Average Precipitation
and
Average Temperature
which are influenced by
latitude
altitude
ocean currents
and affects
where people live
how people live
what they
grow and eat
Climate is influenced by…
Different climates exist because of the way air
circulates over the Earth’s surface
► Determined by:
►
1. Uneven heating of the Earth’s surface
- air is heated much more at the equator
than the poles
- tropical regions near equator are hot
- polar regions are cold
- temperate regions in between are moderate
Climate is Influenced by…
2. Seasonal changes in temperature and
precipitation
- Earth’s axis is tilted, so regions are tipped
toward or away from the sun as the Earth
makes its year-long revolution around the
sun
- creates opposite seasons in northern and
southern hemispheres
23.5º
Spring
(sun aims directly
at equator)
Winter
(northern hemisphere
tilts away from sun)
Solar
radiation
Summer
(northern hemisphere
tilts toward sun)
Fall
(sun aims directly at equator)
Climate is Influenced by…
3. Rotation of the Earth on its axis
- prevents air currents from moving north
and south from the equator
- forms 6 huge cells of swirling air masses
that transfer heat and water from one
area to another
Climate is Influenced by…
4. Long-term variations in solar energy striking the
Earth
- occasional changes in solar output and planetary
shifts (wobbling as it turns)
5. Properties of air and water
- heat from sun evaporates ocean water and
transfers heat from ocean to the atmosphere
- creates convection cells that transport heat and
water from one area to another (leads to
different climates)
LOW
PRESSURE
Heat released
radiates to space
HIGH
PRESSURE
Cool, dry
air
Condensation
and
precipitation
Falls, is compressed, warms
Rises, expands, cools
Warm,
dry air
Hot, wet
air
Flows toward low pressure,
picks up moisture and heat
HIGH
PRESSURE Moist surface warmed by sun
LOW
PRESSURE
Ocean Currents
Factors 1-5 plus differences in water
density create cold and warm ocean
currents
► Currents are driven by winds and Earth’s
rotation
Currents do the following:
1. Redistribute heat from the sun
2. Influence climate and vegetation
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What are Upwellings?
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Movement of nutrient-rich bottom water to
the ocean’s surface
Steep coastal areas where the surface layer
is pushed away from the shore and
replaced by cold, nutrient-rich bottom
water
Very productive area (lots of phytoplankton
and zooplankton)
Upwelling
Movement of
surface water
Wind
Upwelling
Nutrients
El Nino-Southern Oscillation
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In
1.
2.
3.
ENSO
Pacific Ocean - normal upwellings are
affected by ENSO
ENSO:
Winds weaken or cease
Surface waters become warmer
Normal upwellings are suppressed (decline
in productivity and populations of fish)
La Nina
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La
1.
2.
3.
4.
5.
6.
7.
Sometimes El Nino is followed by La Nina
(cooling counterpart)
Nina generally means:
More Atlantic Ocean hurricanes
Colder winters in Canada and Northeast
Warmer and drier winters in southeast and
southwest
Wetter winters in northeast
Torrential rains in SE Asia
Lower wheat yields in Argentina
More wildfires in Florida
El Niño conditions
La Niña conditions
+3
Temperature/Change (°F)
1982–83
1997–98
+2
+1
0
-1
-2
1950
1955
1960
1965
1970
1975
Year
1980
1985
1990 1995 2000
2005
Greenhouse Effect
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Greenhouse gases: water vapor, carbon
dioxide, methane, nitrous oxide, CFCs
►
Play a key role in determining the Earth’s
average temperature (and thus, climate)
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Allow visible light and some radiation and
UV rays from the sun to pass through
troposphere
Greenhouse Effect, continued
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Some of the heat escapes into space
►
Some is absorbed into troposphere which
warms the air
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Greenhouse effect: natural warming effect
of the troposphere
Greenhouse Effect
Rays of sunlight
penetrate
atmosphere
and warm the
Earth’s surface
Some heat escapes
into space; some is
absorbed by
greenhouse gas
molecules which
warm the
atmosphere
As concentration of
greenhouse gases
rise, molecules
absorb more
heat…adds more
heat to atmosphere
Greenhouse Effect, continued
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1.
2.
3.
4.
Without greenhouse gases, Earth would be cold
and lifeless
Human activities (burning fossil fuels, clearing
forests, etc.) create more greenhouse gases
More greenhouse gases can lead to global
warming, which:
Alters rain patterns
Shifts where we can grow crops
Raises average sea levels
Shifts areas where plants and animals can live
Ozone Layer
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In stratosphere, oxygen is continuously
converted to ozone and back again
Caused by UV radiation from the sun
Result: veil of protective ozone
Normally, ozone destruction = ozone
formation
Ozone prevents 95% of sun’s UV rays from
reaching the Earth
Chemicals added to atmosphere by human
activities are decreasing protective ozone
Microclimates
►
Local climate conditions that differ from
the general climate of the region
Ex: Cities whose concrete, asphalt, and
bricks absorb heat and buildings
block wind flow results in more
heat, more smog, lower wind
speeds.
Biomes
A biome is characterized by the climate.
Tundra
Flora
Fauna
Grasses
Dwarf shrubs
Cushion Plants
Arctic foxes
Snoeshoe hares
Snowy owls
Musk oxen
Caribou
Reindeer
Treeless
Tundra
Flora
►Short
and grouped
together
►Use a minimal
amount of energy
Fauna
►Breeding
and
raising young in the
summer
►Hibernation
Adaptations
in the
Tundra
Taiga
Flora
Fauna
Coniferous trees
Red deer
Moose
Migratory birds
Elk
Black bears
Taiga
Flora
►Trees
typically are
evergreens
►Plants grow in
clumps
Fauna
►migrate
to warmer
climates.
►hibernate when
temperatures drop.
►produce a layer of
insulating feathers or
fur to protect them
from the cold.
Adaptations
on the
Taiga
AKA
Temperate Forest
Deciduous Forest
Flora
Fauna
Eagles
Brown Bears
Chipmunk
Red Squirrel
White-tailed deer
Coyote
American Beech
Pecan
White Oak
Carpet Moss
Ferns
Deciduous Forest
Flora
►Thin,
Fauna
broad, light►Birds migrate
weight leaves.
and mammals
hibernate.
►Thick bark
►Cooler temps and limited ►Some tend to
store food.
sunlight causes the tree to
adapt. The leaves are
unable to continue
producing chlorophyll and
change colors.
Adaptations
in the
Deciduous Forest
Grassland
Flora
Fauna
Buffalo Grass
Sunflower
Asters
Coneflowers, Clover
Wild Indigos
Coyotes
Eagles
Bobcats
Wild Turkey
Flies and crickets
Dung Beetle
Bison
Grassland
Flora
►Narrow
leaves that
lose less water to
evaporation.
►Have roots that
extend as much as
3.5 m. for during dry
periods.
►Have brightly
colored flowers.
Fauna
►Are
grazing or
burrowing animals
(flat-topped teeth)
►Are colors that
blend in with the
plant life
Adaptations
in the
Grassland
Desert
Flora
Fauna
Barrel Cactus
Prickly Pear Cactus
Joshua Trees
Tumbleweeds
Armadillo Lizard
Coyote
Tortoise
Proghorn Antelope
Desert
Flora
►store
water in the
roots, stems, leaves
or fruit
►develop shallow
roots
►adapt the size,
sheen, or texture of
their leaves
Fauna
►are
small in size
►stay in shade or
burrowing
underground
►are nocturnal
►concentrate the
body's fat in one
place
Adaptations
in the
Desert
Rain Forest
Flora
Bromeliads
Mangroves
Nepenthes
Fauna
Africa Forest Elephant
Bengal Tiger
Chimpanzee
Linn's Sloth
Orangutan
Toco Toucan
Vampire Bat
Highest biodiversity!!!!
Rain Forest
Temperature
Precipitation
The temperature in a
rain forest rarely
gets higher than 93
°F and rarely drops
below 68 °F
High humidity 7788%
Large amounts of
rainfall: 50 to 260
annually.
50% of the
precipitation comes
from its own
evaporation.
Found near the equator!!!
Rain Forest
Flora
►Thin
smooth bark
►Drip tips... It is
thought that these drip
tips enable rain drops
to run off quickly.
►Large, broad leaves
►Shallow roots
Adaptations
in the
Rain Forest
Fauna
►Prehensile
tails
►Bright colors and
sharp patterns
► Loud
vocalizations
►Diets heavy on
fruits