 Wind
connects
most life on
earth.


Keeps tropics from
being unbearably
hot.
Prevents rest of
world from
freezing.
Figure 7-1
 Concept
7-1 An area's climate is determined
mostly by solar radiation, the earth’s rotation,
global patterns of air and water movement, gases
in the atmosphere, and the earth’s surface
features.
 Weather
is a local area’s short-term physical
conditions such as temperature and
precipitation.
 Climate is a region’s average weather conditions
over a long time.

Latitude and elevation help determine climate.
Fig. 7-2
 Global
air
circulation is
affected by the
uneven heating of
the earth’s surface
by solar energy,
seasonal changes
in temperature
and precipitation.
Corilois Effect
Cold deserts
Air cools and
descends at
lower latitudes.
Westerlies
Forests
30°N
Northeast trades Hot deserts
Warm air rises
and moves
toward the poles.
Air cools and
descends at
lower latitudes.
60°N
Forests
Southeast trades
Equator 0°
Hot deserts
Westerlies Forests
Cold deserts
60°S
30°S
Solar energy
The highest solar
energy input is at
the equator.
Fig. 7-3, p. 142
 Global
air
circulation is
affected by the
properties of air
water, and land.
Figure 7-4
Fig 7.6
 Global

warming:
Considerable scientific evidence and climate
models indicate that large inputs of greenhouse
gases from anthropogenic activities into the
troposphere can enhance the natural greenhouse
effect and change the earth’s climate in your
lifetime.
(a) Rays of sunlight
penetrate the lower
atmosphere and
warm the earth's
surface.
(b) The earth's surface absorbs
much of the incoming solar radiation
and degrades it to longer-wavelength
infrared (IR) radiation, which rises
into the lower atmosphere. Some of this
IR radiation escapes into space as heat,
and some is absorbed by molecules of
greenhouse gases and emitted as even
longer-wavelength IR radiation, which
warms the lower atmosphere.
(c) As concentrations of
greenhouse gases rise,
their molecules absorb
and emit more infrared
radiation, which adds
more heat to the lower
atmosphere.
Fig 7-5
Rain Shadow Effect
Prevailing winds
pick up moisture
from an ocean.
On the windward
side of a mountain range,
air rises, cools, and
releases moisture.
On the leeward side of
the mountain range, air
descends, warms, and
Releases little moisture.
Dry
habitats
Moist
habitats
Fig. 7-7
 Concept
7-2 Differences in average annual
precipitation and temperature lead to the
formation of tropical, temperate, and cold
deserts, grasslands, and forests, and largely
determine their locations.
 Different
climates lead to different communities
of organisms, especially vegetation.


Biomes – large terrestrial regions characterized by
similar climate, soil, plants, and animals.
Each biome contains many ecosystems whose
communities have adapted to differences in climate,
soil, and other environmental factors.
Tropic of
Cancer
Equator
High mountains
Polar ice
Polar grassland (arctic tundra)
Temperate grassland
Tropical grassland (savanna)
Tropic of
Capricorn
Chaparral
Coniferous forest
Temperate deciduous forest
Tropical forest
Desert
Fig. 7-8
 Biome
type is determined by precipitation,
temperature and soil type
Figure 7-10
 Parallel
changes occur in vegetation type occur
when we travel from the equator to the poles or
from lowlands to mountaintops.
Figure 7-9
 Deserts
are areas where evaporation exceeds
precipitation.
 Deserts have little precipitation and little
vegetation.

Found in tropical, temperate and polar regions.
 Desert
plants have adaptations that help
them stay cool and get enough water.
 Variations
in
annual
temperature (red)
and precipitation
(blue) in tropical,
temperate and
cold deserts.
Figure 7-11
 The
flora and
fauna in desert
ecosystems
adapt to their
environment
through their
behavior and
physiology.
 Grasslands
(prairies) occur in areas too moist
for desert and too dry for forests.
 Savannas are tropical grasslands with scattered
tree and herds of hoofed animals.
Fig 7-12
 Temperate
tallgrass prairie
ecosystem in
North America.
Chaparral
Stepped Art
Fig. 7-14, p. 152
 Forests
have enough precipitation to support
stands of trees and are found in tropical,
temperate, and polar regions.
Fig 7-15
 Tropical
rain forests
have heavy rainfall
and a rich diversity
of species.


Found near the
equator.
Have year-round
uniformity warm
temperatures and
high humidity.
Figure 7-16
Fig 7-17
 Consist
mostly of
cone-bearing
evergreen trees that
keep their needles
year-round to help
the trees survive long
and cold winters.
 Concept
7-3 In many areas, human activities
are impairing ecological and economic services
provided by the earth’s deserts, grasslands,
forests, and mountains.
Fig 7-20