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LIVING IN THE ENVIRONMENT, 18e
G. TYLER MILLER • SCOTT E. SPOOLMAN
7
Climate and Biodiversity
©©Cengage
CengageLearning
Learning2015
2015
Core Case Study: A Temperate Deciduous
Forest
• Why do forests grow in some areas and
not others?
– Climate
• Tropical
• Polar
• Temperate
• Temperate deciduous forests
– Globally more disturbed than any other
ecosystem
© Cengage Learning 2015
Three Major Climate Zones
Fig. 7-1, p. 144
7-1 What Factors Influence Climate?
• Key factors that determine an area’s
climate
– Incoming solar energy
– The earth’s rotation
– Global patterns of air and water movement
– Gases in the atmosphere
– The earth’s surface features
© Cengage Learning 2015
The Earth Has Many Different
Climates
• Weather
– Set of physical conditions of the lower atmosphere
– Includes temperature, precipitation, wind speed, cloud
cover in a given area
– Over a period of hours or days
• Climate
– Sum of weather conditions in a given area, averaged
over a long period of time.
– Area’s general pattern of atmospheric conditions
– Ranges from over decades and to thousands of years
© Cengage Learning 2015
The Earth Has Many Different
Climates (cont’d.)
Fig. 7-2, p. 145
The Earth Has Many Different
Climates (cont’d.)
• To determine climate, data must be collected and analyzed on the
average temperature and precipitation in a given area year to year
for at least three decades.
• Based on this analysis, scientists have described the various
regions of the earth according to their climates.
© Cengage Learning 2015
• To help determine regional climates, scientist also study:
– Ocean currents
• Mass movements of surface water driven by winds blowing over the
oceans.
• Help to redistribute heat from the sun, influencing climate and
vegetation
• Heat and differences in water density create warm and cold ocean
currents
• Prevailing winds and irregularly shaped continents cause them to
flow in roughly circular patterns between continents, clockwise in
the northern hemisphere and counterclockwise in the southern
• Water also moves vertically in oceans as denser water sinks while
less dense water rises; a connected loop of deep and shallow
ocean currents that transports warm and cool water to various parts
of the earth.
© Cengage Learning 2015
• Climate varies among the earth’s different
regions primarily because patterns of
global air circulation and ocean
currents distribute heat and precipitation
unevenly between the tropics and other
parts the of the world.
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The Earth Has Many Different
Climates (cont’d.)
• 3 major factors that affect air circulation in
lower atmosphere:
– 1. Uneven heating of the earth’s surface by
sun
• Air is heated much more at the equator, where the
sun’s rays strike directly, than at the poles, where
sunlight strikes at an angle and spreads out over a
much greater area.
© Cengage Learning 2015
– 2. Rotation of the earth on its axis
• As the earth rotates around its axis, the equator
spins faster than the regions to its north and south.
As a result, heated air masses, rising above the
equator and moving north and south to cooler
areas, are deflected in different ways over different
parts of the planet’s surface.
• Divides the atmosphere into regions called cells
• Differing directions of air, prevailing winds, help
to distribute heat and moisture over the earth’s
surface and drive ocean currents.
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• 3. Properties of air, water, and land
• Heat from the sun evaporates ocean water and
transfers heat from the oceans to the atmosphere,
especially near the hot equator.
• Evaporation of water creates giant cyclical convection
cells that circulate air, heat, and moisture both
vertically and from place to place in the atmosphere.
© Cengage Learning 2015
© Cengage Learning 2015
The Earth Has Many Different
Climates (cont’d.)
Moist air rises,
cools, and releases
moisture as rain
Polar cap
Cold
deserts
Evergreen
coniferous forest
60°N
The highest solar
energy input is at
the equator.
Westerlies
30°N
Northeast trades
Temperate deciduous
forest and grassland
Air cools and
descends at
lower
latitudes.
Hot desert
Solar
energy
Tropical deciduous
forest
Equator
Tropical rain forest
Tropical deciduous
forest
Hot desert
Southeast trades
30°S
Westerlies
60°S
Warm air
rises and
moves
toward
the poles.
Temperate deciduous
forest and grassland
Cold
deserts
Air cools and
descends
at lower
latitudes.
Polar cap
© Cengage Learning 2015
Fig. 7-3, p. 146
The Earth Has Many Different Climates (cont’d.)
Warm, less
salty, shallow
current
Cold, salty,
deep current
© Cengage Learning 2015
Fig. 7-5, p. 147
• The ocean and atmosphere are strongly
linked in two ways:
– 1. ocean currents are affected by winds in the
atmosphere.
– 2. heat from the ocean affects atmospheric
circulation.
– Example: El Nino-Southern Oscillation, or
ENSO
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The Earth Has Many Different
Climates (cont’d.)
• El Niño-Southern Oscillation
– Occurs every few years
– Prevailing winds in tropical Pacific Ocean
change direction
– Affects much of earth’s weather for 1-2 years
© Cengage Learning 2015
• What is the link between air circulation,
ocean currents, and biomes?
– Air circulation patterns, prevailing winds, and
configuration of continents and oceans are all
factors in the formation of six giant convection
cells, 3 south of the equator and three north.
– Cells lead to an irregular distribution of
climates and of the resulting deserts,
grasslands, and forests.
© Cengage Learning 2015
Greenhouse Gases Warm the Lower
Atmosphere
• Greenhouse gases
– Absorb some of the solar energy and release
a portion of it as infrared radiation (heat) that
warms the lower atmosphere.
– Play a role in determining the lower
atmosphere’s average temperatures and thus
the earth’s climates.
– H2O, CO2, CH4, N2O
© Cengage Learning 2015
• Natural greenhouse effect
– Gases keep earth habitable
• Human-enhanced global warming
– Like to enhance effect and change the earth’s
climate
– Will likely alter temperature and precipitation
patterns, raise sea levels, and shift areas
where crops are grown and where plants and
animals can live.
© Cengage Learning 2015
Earth’s Surface Features Affect Local
Climates
• Mountains interrupt flow of prevailing
winds and movement of storms.
• Rain shadow effect
– Most precipitation falls on the windward side
of mountain ranges
– Results in deserts leeward (slopes facing
away from wind)
• Cities create microclimates
© Cengage Learning 2015
Earth’s Surface Features Affect Local
Climates (cont’d.)
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,
causing rain shadow effect.
Fig. 7-6, p. 148
7-2 How Does Climate Affect the Nature
and Locations of Biomes?
• 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
© Cengage Learning 2015
Climate Helps Determine Where
Organisms Can Live
• Major biomes
– Large land regions with certain types of
climate and dominant plant life
• Not uniform
• Mosaic of patches
• Change with latitude and elevation
© Cengage Learning 2015
Climate Helps Determine Where Organisms Can Live
(cont’d.)
Cold
Arctic tundra
Evergreen coniferous forest
Temperate
desert
Temperate deciduous forest
Chaparral
Hot
Wet
Cold desert
Temperate
grassland
Tropical desert
Tropical rain forest
Dry
Tropical grassland (savanna)
Fig. 7-7, p. 149
Elevation Mountain ice
and snow
Tundra (herbs,
lichens,
mosses)
Coniferous
Forest
Deciduous
Forest
Latitude
Tropical
Forest
Tropical
Forest
Deciduous
Forest
Coniferous
Forest
Tundra
(herbs,
lichens,
mosses)
Polar ice
and snow
Stepped Art
Fig. 7-8, p. 153
Climate Helps Determine Where
Organisms Can Live (cont’d.)
Fig. 7-9, p. 150
There Are Three Major Types of Deserts
• Desert –
– annual precipitation low and often scattered through the year
– During the day, the baking sun warms the ground and
evaporates water from plant leaves and from soil.
– At night, most of the heat stored in ground radiates quickly into
the atmosphere.
– 1.Tropical deserts
– 2.Temperate deserts
– 3.old deserts
• Why are deserts fragile ecosystems?
© Cengage Learning 2015
There Are Three Major Types of Deserts
(cont’d.)
© Cengage Learning 2015
Fig. 7-10a, p. 150
There Are Three Major Types of Deserts
(cont’d.)
© Cengage Learning 2015
Fig. 7-10b, p. 150
There Are Three Major Types of Deserts
(cont’d.)
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Fig. 7-10c, p. 150
There Are Three Major Types of
Grasslands
• Grasslands occur in:
– Interior continents too moist for deserts and
too dry for forests
• Three main types:
– Tropical
– Temperate
– Cold (arctic tundra)
© Cengage Learning 2015
There Are Three Major Types of Deserts
(cont’d.)
© Cengage Learning 2015
Fig. 7-11a, p. 153
There Are Three Major Types of Deserts
(cont’d.)
© Cengage Learning 2015
Fig. 7-11b, p. 153
There Are Three Major Types of Deserts
(cont’d.)
© Cengage Learning 2015
Fig. 7-11c, p. 153
There Are Three Major Types of
Grasslands (cont’d.)
• 1.Tropical
– Savanna
• Grazing animals
• Browsing animals
• 2.Temperate
– Cold winters and hot and dry summers
– Tall-grass prairies
– Short-grass prairies
– Often converted to farmland
© Cengage Learning 2015
There Are Three Major Types of
Grasslands (cont’d.)
© Cengage Learning 2015
Fig. 7-12, p. 154
There Are Three Major Types of
Grasslands (cont’d.)
• 3.Arctic tundra
– Plants close to ground to conserve heat
– Most growth in short summer
– Animals have thick fur
– Permafrost
• Underground soil that stays frozen
• 3. Alpine tundra
– Above tree line in mountains
© Cengage Learning 2015
There Are Three Major Types of
Forests
•
•
•
•
Forests – lands dominated by trees
Tropical
Temperate
Cold
– Northern coniferous and boreal
© Cengage Learning 2015
There Are Three Major Types of
Forests (cont’d.)
© Cengage Learning 2015
Fig. 7-13a, p. 156
There Are Three Major Types of
Forests (cont’d.)
© Cengage Learning 2015
Fig. 7-13b, p. 156
There Are Three Major Types of
Forests (cont’d.)
© Cengage Learning 2015
Fig. 7-13c, p. 156
There Are Three Major Types of
Forests (cont’d.)
• 1.Tropical rain forests
– Hot and high moisture
– Stratification of specialized plant and animal
niches
– Rapid recycling of scarce soil nutrients
– What is the impact of human activities in the
rain forest?
© Cengage Learning 2015
There Are Three Major Types of Forests (cont’d.)
Emergent
layer
Harpy
eagle
Height (meters)
Toco
toucan
Understory
Wooly
opossum
Brazilian
tapir
Black.crowned
antpitta
© Cengage Learning 2015
Canopy
Shrub
layer
Ground
layer
Fig. 7-14, p. 157
There Are Three Major Types of
Forests (cont’d.)
• 2. Temperate deciduous forests
– Cooler temperature and less moisture
– Broad-leaf deciduous trees
– Slow rate of decomposition
– What is the impact of human activities on
temperate forests?
© Cengage Learning 2015
There Are Three Major Types of
Forests (cont’d.)
• 3.Evergreen coniferous forests: boreal and
taigas
– Cold winters
– Few species of cone-bearing trees
– Slow decomposition
• 3.Coastal coniferous forest, temperate rain
forests
– Found in scattered coastal regions
© Cengage Learning 2015
Mountains Play Important Ecological Roles
• Mountains – steep high elevation lands
– Majority of the world’s forests
– Islands of biodiversity
– Habitats for endemic species
– Help regulate the earth’s climate
– Major storehouses of water
• Role in hydrologic cycle
© Cengage Learning 2015
Mountains
Play
Important
Roles
Mount Rainier
National
Park in Ecological
Washington State
(cont’d.)
Fig. 7-16, p. 159
7-3 How Have Human Activities Affected
the Word’s Terrestrial Ecosystems?
• Human activities are disrupting ecosystem
and economic services provided by many
of earth’s deserts, grasslands, forests, and
mountains
© Cengage Learning 2015
Humans Have Disturbed Much of
the Earth’s Land
• About 60% of the world’s major terrestrial
ecosystems are being degraded
• The human ecological footprint is
spreading across the globe
© Cengage Learning 2015
Natural Capital Degradation
Major Human Impacts on Terrestrial Ecosystems
Deserts
Large desert cities
Destruction of soil and
underground habitat
by off-road vehicles
Grasslands
Conversion to
cropland
Release of CO2 to
atmosphere from
burning grassland
Forests
Mountains
Clearing for
agriculture, livestock
grazing, timber, and
urban development
Conversion of
diverse forests to
tree plantations
Agriculture
Damage from offroad vehicles
Air pollution blowing in from
urban areas and power plants
Depletion of
groundwater
Overgrazing by
livestock
Land disturbance and
pollution from mineral
extraction
Oil production and
off-road vehicles in Pollution of forest
arctic tundra
streams
Timber and
mineral extraction
Hydroelectric dams
and reservoirs
Soil damage from off-road
vehicles
Fig. 7-17, p. 160
© Cengage Learning 2015
Fig. 7-18, p. 160
Size and Locations of Biomes Can Change
• Biomes are not fixed
– They change as the climate changes
• Human activities are likely to affect biome
placement in the future
© Cengage Learning 2015
Size and Locations of Biomes Can Change
(cont’d.)
© Cengage Learning 2015
Fig. 7-19, p. 162
Three Big Ideas
• Differences in climate:
– Based on long-term differences in average
temperature and precipitation
– Largely determine the types and locations of
the earth’s deserts, grasslands, and forests
• The earth’s terrestrial systems provide
important ecological and economic
services
© Cengage Learning 2015
Three Big Ideas (cont’d.)
• Human activities are degrading and
disrupting many of the ecological and
economic services provided by the earth’s
terrestrial ecosystems
© Cengage Learning 2015
Tying It All Together: A Temperate
Deciduous Forest and Sustainability
• Climate plays a key role in determining the
nature of terrestrial ecosystems
• The earth’s dynamic climate system helps
distribute heat from solar energy and
recycle the earth’s nutrients
• In nature, everything is connected
© Cengage Learning 2015