Climate and Terrestrial Biodiversity
Chapter 7
The Earth Has Many Different Climates
• Weather –local areas short term temperature,
precipitation, humidity, wind speed, cloud cover
and other physical conditions of the lower
atmosphere
• Climate – general atmospheric conditions
measured over a long period of time
What Factors Influence Climate?
• 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.
Air circulation in lower atmosphere due to
Uneven heating of the earth’s surface by the sun
Rotation of the earth on its axis
Properties of air, water, and land
Connections between Wind, Climate,
and Biomes
• Wind
– Indirect form of
solar energy,
– part of the earth’s
circulatory system
for heat, moisture,
plant nutrients,
soil particles and
long lived air
Dust blown from West Africa – soil
pollutants
nutrients in Amazonian rain forests,
toxic air pollutants in the US
The Earth Has Many Different
Climates
• Prevailing winds blowing over the oceans
produce mass movements of water called
currents. Driven by prevaining winds and the
earth’s rotation, the major oceancurrents
redistribute heat from the sun from place to
place., thereby influencing climate and
vegetation.
Global Air Circulation
Cold deserts
Air cools and
descends at
lower latitudes.
Westerlies
60°N
Forests
30°N
Northeast trades
Currents
Prevailing winds
Earth’s rotation
Redistribution of
heat from the
sun
Hot deserts
Warm air rises
and moves
toward the poles.
Air cools and
descends at
lower latitudes.
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
Energy
Transfer by
Convection
in the
Atmosphere
LOW
PRESSURE
Cool,
dry air
HIGH
PRESSURE
Heat released
radiates to space Condensation
and
precipitation
Falls, is
compressed,
warms
Rises,
expands,
cools
Hot,
wet air
Warm,
dry air
Flows toward low pressure,
picks up moisture and heat
HIGH
PRESSURE
Moist surface
warmed by sun
LOW
PRESSURE
Fig. 7-4, p. 143
Oceans absorb heat from the
earth’s circulation patterns :
most of this heat is absorbed
in tropical waters, which
receive most of the sun’s heat
Heat and differences in water density (mass/unit volume)
create warm an cold ocean currents.
Prevailing winds and irregularly shaped continents interrupt
these currents and cause them to flow in roughly circular
patterns between the continents
Clockwise – northern hemisphere
Anti clockwise – southern hemisphere
High density cold waters
sinks and flows beneath
warmer and less dense
sea water
Creates a connected loop
of deep and shallow
ocean currents which act
like a giant conveyor belt
Transfers warm and cold
water between the tropics
and the poles
Ocean currents are affected
by winds in the atmosphere
and heat from the ocean
affects atmospheric
circulation
Warm, less
salty, shallow
current
Cold, salty,
deep current
Connected Deep and Shallow ocean currents
Fig. 7-5, p. 143
Moist air rises, cools,
and releases
moisture as rain
Polar cap
Arctic tundra
Global Air Circulation,
Ocean Currents,
and Biomes
Evergreen
60°coniferous forest
Temperate deciduous
forest and grassland
Desert
30°
Tropical deciduous forest
Equator
0°Tropical rain forest
Tropical deciduous forest
30°
Desert
Temperate deciduous
forest and grassland
60°
Polar cap
6 giant
convection cells
moist air rises
,cool dry air
sinks
Fig. 7-6, p. 144
Greenhouse Gases Warm the
Lower Atmosphere
• Greenhouse gases
– H2O
– CO2
– CH4
– N2O
allow mostly visible light and some infra red
Allow visible light , infra red and UV
radiation from the sun to pass through
to pass through the atmosphere
the atmosphere
radiation and some UV radiation from the sun
• Greenhouse effect – long wave length infra red
radiation (heat) rises to the lower atmosphere
• Human-enhanced global warming – burning fossil
fuels, clearing forests
Flow of Energy to and from the Earth
The Earth’s Surface Features Affect
Local Climates
• Heat is absorbed and released more slowly by water
than by land. Creates land and sea breezes
• World’s oceans and large lakes moderate weather and
climate
• Effect of earth’s surface features
– Mountains-interrupt flow of prevailing winds and
movement of storms
• Rain shadow effect
– Cities -Microclimates bricks, concrete, asphalt absorb and
hold heat and buildings block wind flow. Cars release large
amount of pollutants. More haze and smog, higher
temperatures and lower wind speeds
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.
Rain Shadow Effect
Fig. 7-7, p. 145
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.
Climate Affects Where Organisms
Can Live
• Major biomes – large terrestrial regions
characterized by similar climate, soil, plants and
animals. Mosaic of patches each with some basic
similarities but different biological communities
• Latitude and elevation
• Annual precipitation
• Temperature –tropical, temperate, polar
The Earth’s Major Biomes
Effects of Elevation and Latitude on Climate
and Biomes
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
Fig. 7-9, p. 147
Polar
Tundra
Subpolar
Coniferous forest
Temperate
Desert
Deciduous
forest
Grassland
Chaparral
Tropical
Desert
Savanna
Rain forest
Tropical
seasonal
forest
Scrubland
Fig. 7-10, p. 147
There Are Three Major Types of
Deserts
• Tropical deserts
• Temperate deserts
• Cold deserts
• Fragile ecosystem
–
–
–
–
Slow plant growth
Low species diversity
Slow nutrient recycling
Lack of water
Climate
Graphs of
Three
Types of
Deserts
Stepped Art
Fig. 7-11, p. 149
There Are Three Major Types of
Grasslands
• Tropical – savanna : grazing animals, browsing
animals
• Temperate – tall grass prairie and short grass
prairie• Cold (arctic tundra) – permafrost, very fragile
biome
Climate
Graphs of
Tropical,
Temperate,
and Cold
Grasslands
Stepped Art
Fig. 7-12, p. 151
Monoculture Crop Replacing Biologically
Diverse Temperate Grassland
Temperate Shrubland: Nice Climate,
Risky Place to Live
• Chaparral
• Near the sea: nice climate
• Prone to fires in the dry season
Chaparral Vegetation in Utah, U.S.
Stepped Art
Fig. 7-14, p. 152
There Are Three Major Types of
Forests
• Tropical rain forests
– Temperature and moisture
– Stratification of specialized plant and animal
niches
– Little wind: significance
– Rapid recycling of scarce soil nutrients
– Impact of human activities
There Are Three Major Types of
Forests
• Temperate deciduous forests
– Temperature and moisture
– Broad-leaf trees
– Slow rate of decomposition: significance
– Impact of human activities
There Are Three Major Types of
Forests
• Evergreen coniferous forests: boreal and
taigas
– Temperature and moisture
– Few species of cone: bearing trees
– Slow decomposition: significance
• Coastal coniferous forest
• Temperate rain forests
Climate
Graphs of
Tropical,
Temperate
, and Cold
Forests
Stepped Art
Fig. 7-15, p. 154
Tropical
Rain Forest
Ocelot
Harpy
eagle
Blue and
gold macaw
Squirrel
monkeys
Climbing
monstera palm
Katydid
Green tree
Slaty-tailed
snake
trogon
Tree frog
Ants
Bacteria
Bromeliad
Fungi
Producer
to primary
consumer
Primary to
secondary
consumer
Secondary to
higher-level
consumer
All producers and
consumers to
decomposers
Fig. 7-16, p. 155
Stratification
45
40
Harpy
eagle
35
Toco
toucan
Canopy
30
Height (meters)
Emergent
layer
25
20
15
Under
story
Wooly
opossum
10
Brazilian
tapir
5
0
Black-crowned
antpitta
Shrub
layer
Ground
layer
Fig. 7-17, p. 156
Temperate
Rain Forest in
Washington
State, U.S.
Mountains Play Important
Ecological Roles
• Majority of the world’s forests
• Habitats for endemic species
• Help regulate the earth’s climate – snow and ice covers reflect solar
radiation back. Cool earth and off set global warming
• Can affect sea levels by storing and releasing water in glacial ice.
Warmer earth adds water by melting of glaciers
• Major storehouses of water
– Role in hydrologic cycle
Mount
Rainier
National Park
in
Washington
State, U.S.
How Have We Affected the Word’s
Terrestrial Ecosystems?
• In many areas, human activities are impairing
ecological and economic services provided by
the earth’s deserts, grasslands, forests, and
mountains.
Humans Have Disturbed Most of
the Earth’s Lands
• Deserts
• Grasslands
• Forests
• Mountains
NATURAL CAPITAL
DEGRADATION
Major Human Impacts on Terrestrial Ecosystems
Deserts
Grasslands
Forests
Clearing for
Large desert cities Conversion
agriculture,
to cropland
Soil destruction by Release of CO2 livestock grazing,
off-road vehicles
to atmosphere timber, and urban
from burning development
Soil salinization
grassland
Conversion of
from irrigation
diverse forests to
Overgrazing tree plantations
Depletion of
by livestock
groundwater
Damage from offOil production road vehicles
Land disturbance and off-road
and pollution from vehicles in
Pollution of
mineral extraction arctic tundra forest streams
Mountains
Agriculture
Timber extraction
Mineral extraction
Hydroelectric dams
and reservoirs
Increasing tourism
Urban air pollution
Increased ultraviolet
radiation from ozone
depletion
Soil damage from off-road
vehicles
Stepped Art
Fig. 7-20, p. 158