Chapter 5
Climate and Terrestrial
Biodiversity
ATMOSPHERE, CLIMATE, AND BIOMES
Atmosphere
 Thin layer of gases that surrounds the Earth
 Composed of:
 Nitrogen
 Oxygen
 Water vapor
 Argon
 Carbon dioxide
 Neon
 Helium
 Other
Atmosphere has changed
 Early Earth’s atmosphere consisted
only of methane, water vapor,
ammonia and hydrogen
 Photosynthesis greatly changed our
atmosphere! What did this process
add?
Five Layers
Troposphere
Earth’s surface to ~ 6 miles
above the surface
Contains ~ 90% of atmospheric
gases
Where weather occurs
Stratosphere
6 miles to about 30 miles above
Earth’s surface
Air is less dense
Less turbulent air flow
Contains the ozone layer
Mesosphere, Thermosphere,
Exosphere
 Gases become thinner and
thinner
 Colder and colder
 Exosphere merges with outer
space
 What is the difference between
WEATHER AND CLIMATE?
Solar Radiation
 The sun is 93 million miles away, but it has a
profound effect on our atmosphere’s temperature.
 The sun’s energy comes in many forms
 Visible light passes through atmosphere
 UV light is absorbed by ozone
 Infrared radiation is absorbed by CO2, methane, nitrous oxide,
& water
What determines Climate?
Latitude
Air circulation
Ocean currents
Local geography
Latitude
 Distance from
equator
 Amount of solar
energy an area
receives depends on
latitude
 Tilt of Earth on Axis
Air Circulation
 Important properties of air:
 Cool air sinks, and warms as it sinks
 Warm air rises, and cools as it rises
 Warm air can hold more water vapor than cool air
 Solar energy heats the ground
 Due to these properties of air, winds are created
Air Circulation
 Because different
latitudes receive
different amounts of
solar energy,
different patterns of
air circulation are
created…
 These create the
global patterns of
precipitation
 How do air circulation and pressure relate?
The Coriolis Effect
 Winds move in a straight line, but the Earth rotates
beneath them… creating a deflection

Always to the left in the southern hemisphere
Always to the right in the northern hemisphere

video

Cell 3 North
Cold,
dry air
falls
Moist air rises — rain
Polar cap
Arctic tundra
Evergreen
60°coniferous forest
Temperate deciduous
forest and grassland
30°Tropical Desert
Cell 2 North
Cool, dry
air falls
Cell 1 North
deciduous
forest
0°Equator
Tropical
deciduous
30°forest
Tropical
rain forest
Desert
Temperate
deciduous
60°forest and
grassland
Cell 1 South
Cool, dry
air falls
Cell 2 South
Polar cap
Cold,
dry air
falls
Moist air rises,
cools, and releases
Moisture as rain
Moist air rises — rain
Cell 3 South
Fig. 5-6, p. 103
Winds
 The air moving toward the equator from 30° N or S
is deflected by the Coriolis effect to form a wind that
comes dominantly from the east, easterlies. These
easterlies are also called the trade winds
 The air moving from 30°N or S to 60° N and S is
deflected by the Coriolis effect to form a wind that
comes dominantly from the west, westerlies.
Ocean Currents
 Water holds large amounts of heat
 Ocean currents are caused by winds and rotation of
Earth
 Ocean currents influence climate by distributing heat
from place to place and mixing and distributing
nutrients.
 Upwellings- caused by ocean currents and pull
nutrients from bottom of the ocean up
Ocean Currents
 The easterlies push the ocean surface water across
the ocean just north (and just south) of the
equator, forming an equatorial current.
 This equatorial current flows until it hits land. It is
then deflected to the right in the northern
hemisphere to form a western boundary current.
 In the North Atlantic, this current is called the Gulf
Stream.
Ocean Currents
 Western boundary currents bring warm water
from the equator to cooler, higher latitudes.
 After flowing along the western side of the ocean,
the current deflects again, crossing the ocean. It
reaches the eastern side and deflects again,
running back to the equator as an eastern
boundary current.
 Eastern boundary currents bring cool water from
high latitudes toward the equator. In the Pacific,
the eastern boundary current is called the
California Current.
The uneven heating of
the planet by the sun
drives the atmospheric
and oceanic circulation,
which in turn causes
the Earth's climate to
vary by latitude.
We recognize climate
zones, from equator to
poles:
•tropics
•subtropics
•temperate
•polar
Extreme Weather Changes
EL NINO= WARMING
LA NINA= COOLING
 VIDEO
 Cools coastal water and
 A sudden change in
tropical winds warms
coastal surface water,
suppresses upwellings,
and alters climate
temporarily.
brings back upwellings.
Geography of the land
 Topography of the land can greatly
affect climate
 Continents are places for extra
heating
 Mountains shift winds upward and
create added precipitation
Topography and Local Climate:
Rain Shadow Effect
 Interactions between land and oceans and
disruptions of airflows by mountains and cities
affect local climates.
Figure 5-8
Climate
 There are many factors that determine your local
climate, but ultimately it is…




Latitude
Air circulation
Ocean currents
Local geography
 And the most important factor of all… SOLAR
ENERGY!!
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.
BIOMES:
CLIMATE AND LIFE ON LAND
Figure 5-9
Polar
Tundra
Subpolar
Temperate
Coniferous
forest
Desert
Deciduous
Forest
Grassland
Chaparral
Tropical
Desert
Rain forest
Savanna
Tropical
seasonal
forest
Scrubland
Fig. 5-10, p. 107
Desert Biomes
 Deserts are areas where evaporation exceeds
precipitation.
 Deserts have little precipitation and little vegetation.
 1. Tropical deserts are hot, dry most of the year with few
plants, rocks and sand.
 2. Temperate deserts have high day temperatures in
summer, low temperatures in winter with more rain than
in tropical deserts. Plants are widely spaced, mostly
drought-resistant shrubs, cacti/succulents.
 3. Cold deserts have cold winters, warm summers with
low rainfall.
Desert plant and animal adaptations
 Desert plants and animals have adaptations that help them





stay cool and get enough water to survive. Adaptations
include:
1. Plants that drop leaves during hot dry spells to survive in
dormant state.
2. Plants may have no leaves, they store water in fleshy
tissue, and open pores to have gas exchange only at night.
3. Some plants have very long taproots to reach
groundwater.
4. Evergreen plants have thick, waxy leaves to reduce
evapotranspiration.
5. Annuals store biomass in seeds that may be dormant for
years.
Adaptations continued
 6.
Most animals are small. They may only come out at
night or early morning. Others become dormant during
extreme heat or drought.
 7. Insects/reptiles have thick outer coverings to
conserve water. Wastes are dry feces and concentrated
urine.
 8. Desert ecosystems are fragile and take a long time to
recover from disturbances due to slow plant growth, low
species diversity, slow nutrient cycling, and lack of water.
Human impact on deserts due to overgrazing and offroad vehicles may take decades to overcome.
Tropical Grasslands (Savannah)Biomes
 They have scattered trees and enormous herds of hoofed




animals.
A savanna usually has warm temperatures, two long dry
seasons with much rain the rest of the year.
1. Large herds of grazing (grass) and browsing (twig
and leaf) animals feed here.
2. Competition for plant materials has been minimized
due to specialized eating habits.
3. Human attempts to raise cattle on savannas, and the
use of trees for firewood, have converted savanna to
desert.
Temperate Grasslands
 They have cold winters and hot and dry summers have deep and fertile soils
that make them widely used for growing crops and grazing cattle.
 They are widely distributed in North and South America, Europe, and Asia.
 1.






Organic matter accumulates, producing fertile soil, as aboveground
plant parts die each year.
2.
Soil held in place by network of intertwined root.
3.
Natural grasses are adapted to fire.
4.
North American grasslands are tall-grass prairies and short-grass
prairies.
5.
Evaporation is rapid, winds blow most of the time and fires occur in
summer and fall.
6.
Humans have used these lands to raise cattle and crops. They are
often flat areas, easily plowed.
7.
Plowing makes soil vulnerable to erosion and blowing.
Polar Grasslands (Arctic Tundra)







Polar grasslands are covered with ice and snow except
during a brief summer.
Long, dark winters and low precipitation.
1. Under the snow there is a thick, spongy mat of lowgrowing vegetation (grasses, mosses, dwarf woody shrubs)
2. Most growth occurs within 6-8 weeks of summer during
the long hours of daylight.
3. Permafrost is a permanently frozen layer of soil when
water freezes.
4. Tundra is waterlogged during summer, with hordes of
insects.
5. Migratory birds nest and breed in bogs and ponds during
summer.
Polar grasslands continued
 6.
Animals are mostly small herbivores such as
lemmings, hares, voles that can burrow.
 7. Predators include lynx, weasel, snowy owl and
artic fox.
 8. Decomposition is slow, soil is poor in organic
matter
 9. Human activities such as oil drilling, mining
have scarred the landscape, which is very slow to
recover.
Chaparral
 Chaparral has a moderate climate but its dense thickets






of spiny shrubs are subject to periodic fire.
Chaparral is found in coastal areas that border deserts.
1. The winter rainy season is longer than in desert, fog
during spring/fall reduces evaporation.
2. Low-growing, evergreen shrubs with occasional
trees is vegetation type.
3. Fires move swiftly when started in these areas.
4. Humans like the climate (Southern Cali.) of this
biome, but risk losing homes to fire.
5. Floods/mudslides occur after fires at times. WHY?
Tropical Rain Forest






Tropical rain forests have heavy rainfall on most
days and a rich diversity of species occupying a variety of
specialized niches in distinct layers.
Tropical rain forests are near the equator, and have hot
humid conditions.
Dominant plants are broadleaf evergreens with shallow
roots.
A dense canopy blocks most sunlight from reaching
lower levels.
Vines often drape individual trees.
Epiphytes such as orchids and bromeliads are found on
trunks and branches.
Tropical Rain forest continued
 Most animal life is found in the sunny canopy layer of the





forest.
Tropical forests cover about 2% of the land surface, but
are habitats for about half the terrestrial species of earth.
Very little litter is on the forest floor because of rapid
recycling of dead materials.
The acidic soil makes these areas poor places to grow
crops or graze cattle.
So far at least 40% of these forests have been destroyed
or disturbed by human activities.
Tropical dry forests are found in tropical areas with
warm temperatures year round and wet and dry seasons.
Temperate Deciduous Forest
 Temperate deciduous forests grow in areas with




moderate average temperatures, abundant rainfall and
long, warm summers.
Most of the trees in these forests survive winter by
dropping their leaves, which decay and produce nutrientrich soil.
Broadleaf, deciduous trees dominate this biome.
More sunlight penetrates the canopy so there is richer
diversity of ground level plant life.
A thick layer of leaf litter is usual due to fairly slow
decomposition.
 Large predator species such as bear, wolves, wildcats,
and mountain lions have been killed; deer and smaller
mammals are now often the dominant species.
 Large tracts of temperate forest have been cleared,
planted in a single species of tree (tree plantations).
 Bird species migrate to and from these areas to breed
and feed. They are declining due to loss of habitat.
 This biome has been disturbed by human activity more
than any other terrestrial biome as a result of
establishing settlements, industrialization, and
urbanization.
Evergreen Coniferous Forest: Boreal Forest
 Located in areas just south of arctic tundra around the northern sub-arctic
regions of the earth.
 These forests consist mostly of cone-bearing evergreen trees that keep their
needles year-round to help the trees survive long cold winters.
 Long, dry, extremely cold winters with 6-8 hours sunlight are the norm.
 Summers are short with 19 hours of daily sunlight.
 Dominant trees are coniferous (cone-bearing) spruce, hemlock, fir, cedar




and pine.
Decomposition is slow because of low temperatures, waxy narrow leaves
and high soil acidity. Soil is nutrient poor.
Wildlife include bears, wolves, moose, lynx and many burrowing rodent
species.
Acidic bogs form is summer.
During summer birds feed on the many insects.
Temperate Rain Forest: Coastal Coniferous
Forest
 Coastal areas support huge cone-bearing evergreen




trees such as redwoods and Douglas fir in a cool and
moist environment.
Located along the western coast of Canada to
northern California.
1. Most trees are evergreen with much moss and
epiphytes.
2. There is a dense canopy with little light reaching
the forest floor.
3. The winters are mild and summers are cool.
Mountain Biomes
 Mountains are high-elevation forested islands of




biodiversity.
Often have snow-covered peaks and gradually release
water to lower-elevation streams and ecosystems.
Mountains are places with dramatic changes in altitude,
climate, soil and vegetation within very short distances.
1. They are prone to erosion when vegetation is
removed by natural disturbances, or human activities.
2. Mountains have important ecological roles such as
habitats for endemic species, biodiversity, and
sanctuaries for animal species driven from other
habitats.
Mountains continued
 3.
They help regulate earth’s climate, snow peaks
reflect much of solar radiation into space.
 4. Mountains play a major role in the hydrologic
cycle. (storing and releasing water)