Environmental Science
Chapter 6 Lecture
Biomes
Chapter 6 Targets
1. I can describe how plants determine the name of a
biome.
2. Using a world map, I can identify general locations of
the world’s biomes.
3. I can define climate and explain how temperature
and precipitation determine which plants grow in an
area.
4. I can explain how latitude and altitude
affect which plants grow in an area.
Biomes and Vegetation (Plants)
T1
• Biomes: large regions characterized by a specific climate
and plant and animal communities
• Each biome is made of many different ecosystems
• Biomes are described by their PLANTS
– Plants determine what other organisms that can live
there
– Plants have traits, special structures, or adaptations that
allow them to survive in specific biome
– Adaptations include size, shape, and color
– Example: tundra plants tend to be short because
they don’t get enough water to grow larger
– Other examples??
The World’s Major Terrestrial Biomes
T2
T2
Biomes and Climate
T3
• Climate: average weather conditions in area over
long period of time
– Main factor in determining which plants can
grow in certain area defines the biome.
– Temperature and precipitation are most
important factors determining climate (see video)
Temperature and Precipitation
• -Most organisms don’t survive at temperatures too far
above/below a range they have adapted to
• -Precipitation limits organisms found in a biome
– -↑ plant size = ↑ water it needs
-Biomes receiving low amounts of rainfall support
communities dominated by small trees, shrubs,
and grasses
-In biomes where rainfall is not frequent, plants
are mostly cacti and desert shrubs
-In extreme cases, lack of rainfall results in no
plants, no matter what the temperature is
• -↑ temperature + ↑precipitation = ↑ plants
T3
T3
Latitude and Altitude
T4
• Latitude: distance north or south from equator (expressed in degrees)
• Altitude: height of an object above a reference point, such as sea level
or the Earth’s surface.
– Climate varies with latitude and altitude.
– Climate gets colder as latitude and altitude increase.
– This is why it gets colder as you move further up a mountain.
T4
Comprehension Check
According to the maps, which of the
following determines the main
characteristics of a biome?
A. Geographic borders
B. Latitude
C. Longitude
D. Distance from the ocean
Comprehension Check
Which of the following describes a biome?
A. All the areas on Earth that are lifesupporting
B. Weather conditions in an area for a
specific time period
C. A region characterized by specific
climate and organism communities
D. An area where the animal population
interacts with its abiotic environment
Comprehension Check
What is the diversity of the species in an
area most dependent on?
A. Plant life
B. Rainfall
C. Sunlight
D. Temperature
Comprehension Check
What are the main factors that determine
weather?
A. Altitude, latitude, precipitation, temperature
B. Altitude, latitude, precipitation, vegetation
C. Air currents, altitude, temperature,
vegetation
D. Air currents, precipitation, temperature,
vegetation
Chapter 6 Targets
5. Based on climate, I can predict where forest biomes are
located.
6. I can list three characteristics of tropical rain forests and
identify their location on a world map.
7. I can name and describe the main layers of a tropical rain
forest.
8. I can name the main threats to rain forests and the global
effects of rain forest destruction.
9. I can list three characteristics of temperate rain
forests and identify their location on a world map.
Forest Biomes
T5
• Of all biomes in the world, forests are most
widespread and diverse
• Because trees need a lot of water, forests are found
where temperatures are mild to hot and rainfall is
plenty
• 3 main forest biomes of the world:
1. Tropical
2. Temperate
3. Coniferous
Tropical Rain Forests
• Forests/jungles near equator
characterized by:
– 1. large amounts of rain
– 2. little change in
temperature
– 3. greatest biodiversity on
Earth
– 4. humid, warm, and strong
sunlight
• Regulate climate and play
a role in nitrogen, oxygen,
and carbon cycles.
T6
Nutrients in Tropical Rain Forests
T7
• Most nutrients are in plants, not soil
– Decomposers on forest floor break down dead
organisms  return nutrients to soil  plants
quickly absorb the nutrients
– There are so few nutrients in the soil that runoff
from rain forests is often as pure as distilled
water
• Most tropical soils cleared for agriculture cannot
support crops for more than a few years
• Many trees form above-ground roots
called buttresses or braces that grow
sideways from tree to provide extra
support in the thin soil
Layers of the Rain Forest
• In tropical rain forests, different types of plants grow in
different layers
• 4 main layers of the rain forest:
•
•
•
•
1. The Emergent Layer
2. The Upper Canopy
3. The Lower Layer
4. The Understory
T7
Layers of the Rain Forest
• Emergent layer: top leaf
layer where tallest trees
extend above everything else
– Trees reach direct sunlight
at heights of 60-70 m (~23
stories tall) and can
measure up to 5 m around
– Animals such as eagles,
bats, monkeys, and
snakes live in the
emergent layer
T7
Layers of the Rain Forest
• Canopy: layers of
treetops that shade forest
floor
– Considered main layer
of rain forest
– Trees form dense
layer that absorbs up
to 95% of sunlight
– Can be split into upper
and lower canopy with
lower canopy receiving
less sunlight
understory
T7
Layers of the Rainforest
T7
• Epiphytes: plants that grow on another
plant but do not harm it
– Located on tall trees in canopy to
reach sunlight for photosynthesis,
and absorb water and nutrients
• Most animals living in the rain forest
live in canopy because they depend on
the many flowers and fruits that grow
there.
Layers of the Rainforest
T7
• Understory: plant layer beneath and shaded by
main canopy of a forest
– Little light reaches this layer allowing only trees
and shrubs adapted to shade to grow here
– Most plants in understory are less than 3.5 m
tall
Threats to Rain Forests
T8
• Every minute, 100 acres of tropical rainforest are
cleared or damaged for:
1. Logging operations
2. Agriculture
3. Oil exploration
4. Exotic-pet trading
• ~50 million native people live in tropical rain forests
and are threatened by habitat destruction
– Loss of habitat forces them to move to cities
– This drastic lifestyle change may force them to
lose their culture and traditions
Temperate Rain Forests
T9
• Characterized by:
1. cool, humid weather
2. heavy rainfall
3. tree branches draped with mosses
4. tree trunks covered with lichens
5. forest floor covered with ferns
Found in North America, Japan
Australia, and New Zealand
Temperate Rain Forest Climate
• Pacific Northwest keeps
mild temperatures year
round
• Rarely freezes because
Pacific Ocean blows
cool ocean water over
forest (regulates temp)
• As ocean winds meet
Olympic Mountains, a
large amount of rainfall
is produced, keeping
temperature cool and
moist
T9
Chapter 6 Targets
11. I can list three characteristics of temperate deciduous forests
and identify their location on a world map.
12. I can describe one plant in a temperate deciduous forest and
an adaptation that helps the plant survive.
13. I can list two characteristics of taigas and identify their
location on a world map.
14. I can identify unique characteristics of conifers.
15. I can describe one adaptation that help animals survive in
taiga.
Temperate Deciduous Forests
•
T 11
Characterized by:
1. Trees shed leaves in fall
2. Located between 30º and 50º north latitude.
3. Range of temperatures can be extreme; summer temps
soaring to 35ºC (95oF) and winter temps often falling
below freezing
4. 75 to 125 cm (29-49 inches) of precipitation annually, helps
decompose dead organic matter into rich soils
Temperate Deciduous Forest
Locations
T 11
Plants of Deciduous Forests
• Plants grow in layers with tall trees like
birch that dominate the canopy and
shrubs cover the understory (no
emergent layer)
• More light reaches deciduous forest floor
than rain forest floor allowing more small
plants to grow
• Plants are adapted to survive seasonal
changes
– In fall and winter, trees shed leaves
and seeds go dormant under
insulation of the soil
– With returning warmth in spring, trees
grow new leaves and seeds sprout
T 12
Taiga (Boreal Forest)
T 13
• Region of evergreen, coniferous forest below
arctic and subarctic tundra regions.
– has long winters and little vegetation.
– growing season short (50 days) with most
plant growth during summer months because
of nearly constant
daylight and larger
amounts of
precipitation.
Taiga Video (11")
Taiga Locations
T 13
Plants of the Taiga
T 14
• Conifers: trees that have seeds that develop in cones
– Leaves’ arrow shape and waxy coating help retain
water in winter
– Conifer’s shape helps tree shed snow and not get
weighed down
– Conifer needles contain substances that make soil
acidic when they fall, preventing plants from growing on
the floor
– Soil forms slowly because climate and acidity slow
decomposition
Animals of the Taiga
• Taiga has many lakes and
swamps attracting birds that
feed on insects during the
summer
• To avoid harsh winters, birds
migrate
• Some year-round residents,
such as shrews, burrow
underground for better
insulation.
• Other animals avoid
predation by shedding brown
summer fur and growing
white fur to camouflage them
in the snow
T 15
Snowshoe Hare
Comprehension Check
What type of forest has the
greatest biodiversity?
A. Taiga forest
B. Temperate deciduous forest
C. Temperate rain forest
D. Tropical rain forest
Chapter 6 Targets
16. I can describe the climate and locations of savannas.
17. I can describe adaptations of savanna plants and
animals.
18. I can describe the climate and locations of temperate
grasslands.
19. I can explain why fire is important to grassland and
savanna biomes
20. I can describe adaptations of temperate grassland
plants and animals.
21. I can describe how farming and
overgrazing have destroyed temperate
grasslands.
Savannas
• Plains full of grasses, scattered
trees and shrubs
• Found in tropical and
subtropical habitats
• Mainly in regions with dry
climate, such as East Africa
and western India
• Have wet and dry seasons
(though ↓ precipitation)
– Many animals active only
during wet season
– Grass fires restore nutrients
to soil during dry season
T 16
Savannas
T 16
Plants of the Savanna
• Only rains during wet season,
plants must be able to survive
prolonged periods without water
1. Some plants have large
horizontal root systems to help
them survive dry season.
These roots also enable them
to grow quickly after fire.
2. Grasses have coarse vertical
leaves that expose less
surface area to conserve
water, while some trees shed
their leaves.
3. Almost all have thorns for
protection from herbivores.
T 17
Animals of the Savanna
1. Grazing herbivores, like
elephants, migrate, following
rains to areas of new grass
and fresh watering holes.
2. Many savanna animals give
birth only during rainy
season, when food is
abundant and young are
more likely to survive.
3. Some species of herbivores
reduce competition for food
by eating vegetation at
different heights than other
species do.
T 17
Temperate Grasslands
• Temperate grasslands:
– Dominated by grasses, few
trees
– Hot summers and cold
winters
– Amount of rainfall is between
that of a forest and a desert
– Most fertile soil of any biome
• Few natural temperate
grasslands remain
because most have been
replaced by grazing areas
and farms growing crops
such as corn, soybeans,
and wheat
T 18
Temperate Grasslands
• Located where too little rain
falls for trees to grow
• Mountains often play a role in
forming grasslands because
they block rain clouds from the
west
– Rainfall does ↑ as you move
east, allowing taller grasses
to grow.
• Heavy precipitation is rare in
grasslands, so hot
temperatures in summer often
create fires
T
18/19
Temperate T 18
Grasslands
Classifying U.S. Grassland Types
T 18
• U.S. grasslands (prairies) classified by
examining 2 things:
1. Annual Precipitation
2. Soil Type:
• MESIC: dark black soil, rich in nutrients
» drains well, yet retains some water
• LOESS: “glacier dust”
» Mineral particles mixed with clay
• DOLOMITE: near fens
» High pH
» Formed from calcium carbonate (limestone)
that has been worn down
Plants of Temperate Grasslands
T 20
1. Root system of prairie grasses forms dense
layers that survive drought and fire, allowing
plants to come back from year to year
2. Few trees survive on grasslands because of
low rainfall, frequent fire, and constant winds
3. Amount of rainfall in the area determines
types (varying root depth and grass height) of
plants that will grow in that area
Grassland Plants
~35 inches rain
~10 inches rain
~20 inches rain
T 20
Animals of Temperate Grasslands
T 20
1. Some grazing animals, such as bison and
pronghorn antelope, have large, flat teeth for
chewing the coarse prairie grasses.
2. Other grasslands animals, such as prairie
dogs, owls, and badgers, live protected in
underground burrows that protect them from
predators on the open grasslands.
Threats to Temperate Grasslands
T 21
• Farming/overgrazing have changed
grasslands
• Crops don’t hold soil in place as well as
native grasses because their roots are
shallow, soil erosion eventually occurs
• Constant farming can change fruitful
grasslands into desert-like biomes
Chapter 6 Targets
22. I can describe the climate and locations of the chaparral
biome.
23. I can describe adaptations of chaparral plants and animals.
24. I can describe the climate and locations of desert biomes
25. I can name two desert animals and plants, and describe the
adaptations that help them survive.
26. I can describe the climate and location of the tundra biome.
27. I can name two tundra animals and plants, and describe the
adaptations that help them survive.
28. I can describe one threat to the tundra biome.
Chaparral
• Chaparral
T 22
– temperate woodland biome
– plants are broad-leaved evergreen shrubs
– located in areas with hot, dry summers and mild, wet
winters
• Located in middle latitudes, about 30° north and
south of the equator.
» Primarily in coastal areas with Mediterranean climates.
Chaparral
T 22
Plants of the Chaparral
T 23
• Most are low-lying, evergreen shrubs
• Some small trees grow in dense
patches
• Include chamise, manzanita, scrub
oak, and herbs like sage and bay.
• Have small, leathery leaves that
contain oils to promote burning,
allowing natural fires to destroy
competing trees.
• Well adapted to fire and can regrow
from small bits of surviving plant
tissue.
Animals of the Chaparral
T 23
• Common adaptation is camouflage, shape or
coloring allowing animals to blend into
environment
– Quail, lizards, chipmunks, and mule deer
have a brownish gray coloring that lets
them move through the brush without
being noticed.
What is a Desert Like?
T 24
• Land of extremes: extreme heat and
extreme dryness; sudden flash floods and
cold nights.
• Very harsh, often have names likes "Death
Valley," "the empty quarter," and "the place
from where there is no return."
Dryness
T 24
• VERY dry. Even wettest deserts get less than ten
inches of precipitation a year.
Hot During the Day, Cool at Night
T 24
• During day many deserts are very hot.
Temperatures in excess of 100oF are
common.
• Yet at night, temperatures fall into the
40s or 50s? Why?
T 24
-Other biomes insulated by humidity.
-At night water acts like a blanket,
trapping heat inside the biome
-Deserts have only 10-20% humidity to trap
temperatures.
-Have few trees and other plants to retain
heat
-Deserts cool down rapidly when sun sets 
heat up quickly after sun rises
Where Are Deserts Located?
T 24
Many are found in bands along 30o north
and 30o south of the equator* (called
the desert belt)
*between red lines on the map
Why do “desert belts” form?
• As warm air rises over
equator rises, it cools and
loses moisture
• As it falls (north and south
of the equator), it warms
and picks up moisture,
drying out the land
• This downward movement
of warm air masses over
the earth has produced
two belts of deserts
T 24
The Rain Shadow Effect
T 24
• Deserts near mountains are caused by "rain shadow"
effect
• As air moves up over mountains, it gets cold and loses
moisture -- causing rain or snow
• When air moves down the other side of the mountain,
it gets warmer.
• Warm air can hold more moisture, so it doesn't rain as
much, and a desert is formed.
Deserts of North America
T 24
NOTE: All deserts in North America are
influenced by the rain shadow effect
Desert Plant Adaptations
T 25
Plants adapt to dryness by reducing rates of
evapotranspiration:
1. reduced leaves (spines)
2. waxy coating on leaves and stems
3. store water in fleshy parts (succulents)
4. large, shallow root systems absorb water
quickly –or- deep taproots
5. mature quickly and produce flowers/seeds in
the few days when water is available
6. seeds in some can remain dormant for over 50
years
Desert Animal Adaptations
• Usually small (ex. Jackrabbits, snakes, and kangaroo
rats)
• Adapted to conserve water:
1. get water from their own respiration
2. excrete concentrated urine
3. camel’s hump?
Camel's Hump Video
• Adapted to survive in temperature extremes:
1. Nocturnal
2. Burrow
3. Estivate
T 25
Tundra
T 26
• Tundra: treeless plain located in Arctic or Antarctic,
characterized by:
– Very low winter temperatures
– Short, cool summers
– Plants are grasses, lichens, and perennial herbs.
– Short summers , only the top few centimeters of
soil thaw.
• Permafrost: the permanently frozen layer of soil or
subsoil found in tundra regions.
T 25
Tundra Locations
Tundra Plants/Producers
T 27
• Mosses and lichens cover vast areas of rocks
in the tundra (why would these be able to grow
here?)
• Other plants have wide shallow roots to help
anchor them against icy winds in the thin soil
• Most flowering plants are short, this keeps
them out of the wind and helps them absorb
heat from the sunlit soil
• Woody plants and perennials have evolved
dwarf forms that grow flat along the ground
Tundra Animals Adaptations
T 27
• Migratory birds fly to tundra to breed in summer when
food is abundant.
• Caribou migrate throughout tundra in search of food
and water. Predators such as wolves prey on
migratory caribou, deer, and moose.
• Rodents stay active, but burrow under the snow to
avoid the cold.
• Only tundra animal to hibernate is arctic ground
squirrel
• Other year-round residents, such as arctic foxes, lose
brown summer coat for white fur to camouflage them
with the snow
Threats to the Tundra
T 28
• One of the most fragile biomes on planet.
• Food chains are simple and easily disrupted.
• When oil was located in parts of tundra, oil
exploration, extraction, and transport disrupted
many tundra habitats
• Pollution caused by spills or leaks of oil and
other toxic materials may also poison food and
water sources in tundra