Chapter 7
Climate and Terrestrial
Biodiversity
Core Case Study
Blowing in the Wind:
A Story of Connections
• Wind connects most
life on earth.
– Keeps tropics from
being unbearably
hot.
– Prevents rest of
world from freezing.
Figure 7-1
7-1 What Factors Influence
Climate?
• 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.
CLIMATE: A BRIEF
INTRODUCTION
• 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
Animation: Climate and Ocean
Currents Map
PLAY
ANIMATION
Solar Energy and Global Air
Circulation: Distributing Heat
• Global air circulation
is affected by the
uneven heating of the
earth’s surface by
solar energy, seasonal
changes in
temperature and
precipitation.
Video: Seasonal Variation
PLAY
VIDEO
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
Convection Currents
• Global air
circulation is
affected by the
properties of air
water, and land.
Figure 7-4
Global Air
Circulation,
Ocean Currents,
and Biomes
Fig 7.6
Animation: Air Circulation and
Climate
PLAY
ANIMATION
Ocean Currents:
Distributing Heat and Nutrients
• 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.
Connected Deep and Shallow
Ocean Currents
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
7-2 How Does Climate Affect the
Nature and Locations of Biomes?
• 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.
BIOMES:
CLIMATE AND LIFE ON LAND
• 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
BIOMES:
CLIMATE AND LIFE ON LAND
• Biome type is determined by precipitation,
temperature and soil type
Figure 7-10
BIOMES:
CLIMATE AND LIFE ON LAND
• Parallel changes occur in vegetation type
occur when we travel from the equator to
the poles or from lowlands to mountaintops.
Figure 7-9
DESERT BIOMES
• 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.
DESERT BIOMES
• Variations in
annual
temperature (red)
and precipitation
(blue) in tropical,
temperate and
cold deserts.
Figure 7-11
DESERT BIOMES
• The flora and
fauna in desert
ecosystems
adapt to their
environment
through their
behavior and
physiology.
GRASSLANDS AND CHAPARRAL
BIOMES
• 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.
Climate Graphs of Tropical, Temperate, and
Cold Grasslands
Fig 7-12
Temperate Grasslands
• Temperate tallgrass prairie
ecosystem in North
America.
Chaparral
Stepped Art
Fig. 7-14, p. 152
FOREST BIOMES
• Forests have enough precipitation to support
stands of trees and are found in tropical,
temperate, and polar regions.
Climate Graphs of Tropical, Temperate, and
Cold Forests
Fig 7-15
Tropical Rain Forest
• 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
Stratification of Specialized Plant and Animal
Niches in a Tropical Rain Forest
Fig 7-17
Evergreen Coniferous Forests
• Consist mostly of
cone-bearing
evergreen trees
that keep their
needles year-round
to help the trees
survive long and
cold winters.
7-3 How Have We Affected the
Word’s Terrestrial Ecosystems?
• Concept 7-3 In many areas, human
activities are impairing ecological and
economic services provided by the earth’s
deserts, grasslands, forests, and mountains.
Major Human Impacts on Terrestrial
Ecosystems
Fig 7-20