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CHAPTER 6
BIOMES
6-1 What is a biome?
1. What is a biome?
• A large region
characterized by a
specific type of
climate and certain
types of plants and
animal communities.
2. What is a terrestrial biome?
• A terrestrial biome is a land biome.
• The major terrestrial biomes are:
– Tropical rain forest
– Temperate forest
– Taiga
– Tropical savanna
– Temperate grassland
- Chaparral
- Desert
- Tundra
- Mountains
Terrestrial Biomes
3. What is the name of the biome
often based on?
• The plant life in the area (this determines
what other organisms can live there)
• The climate determines the type of plants
that live there
• The plants in a particular biome have
characteristics (adaptations) that allow
them to survive in that biome.
4. What is climate?
• Refers to the average weather conditions in an
area (temperature, precipitation, humidity,
winds) over a long period of time
5. What are the 2 most important
factors in a regions climate?
• Temperature
• precipitation
6. How do temperature and
precipitation determine what
lives in the biome?
• Biomes that do not receive enough rainfall to
support large trees, support communities
dominated by small trees, shrubs, and grasses.
• In biomes with very little rainfall, the vegetation
is mostly cactuses and desert shrubs.
• The higher the temperature and precipitation
are, the taller and denser the vegetation is.
7. How do latitude and altitude
affect climate?
• Latitude – the distance north or south from
the equator, expressed in degrees
• Altitude – the height of an object above
sea level
• Climate varies with altitude and latitude
• The climate generally gets colder as
latitude and altitude increase and it gets
warmer as altitude and latitude decrease.
• As latitude and altitude increase, biomes
and vegetation change.
• Trees of tropical rainforests usually grow
closer to the equator, while mosses and
lichens of the tundra grow closer to the
poles.
• The temperate region includes biomes
such as temperate forests and grasslands,
which have moderate temps and fertile soil
that is good for agriculture.
8. What are the different regions
of latitude?
• 0° to 30° - Tropical
• 30° to 60° - Temperate
• 60° to 90° - Arctic
Latitude and Altitude
6-2 Forest Biomes
1. What are the forest biomes?
• Of all the biomes in the world, forest
biomes are the most widespread and the
most diverse.
• The large trees of forests need a lot of
water, so forests can be found where
temperatures are mild to hot and where
rainfall is plenty.
• There are three main forest biomes of the
world: tropical, temperate, and coniferous
2. What are some characteristics
of the tropical rain forest?
• Occurs in a belt around the Earth near the
equator
• Sometimes called jungles
• Help regulate world climate and play vital
roles in the nitrogen, oxygen, and carbon
cycles
• Humid and warm
• Rains a lot (80-180in/year) (200450cm/year)
More characteristics of the
Tropical Rain Forest
• Gets strong sunlight year round
• Little seasonal variation
• More different species of plants grow here
than in any other biome
• Thin/poor soil
Tropical Rain Forest
Major Rainforests of the World
3. How are plants adapted to living
in a tropical rain forest?
• Most nutrients are within the plants instead of in
the soil.
• Nutrients from dead organic matter are removed
so efficiently that runoff from rain forests is often
pure as distilled water.
• Most tropical soils that are cleared of plants for
agriculture lack nutrients and cannot support
crops for more than a few years.
• Many trees form above ground roots called
buttresses or braces that grow sideways from
the tree to provide it with extra support in the thin
4. What are the layers of
vegetation in the tropical
rainforest?
• Plants grow in layers:
– Emergent layer
– Upper Canopy
– Lower layer
– Understory
Layers of the Rainforest
5. What are some
characteristics of the emergent
layer?
• The emergent layer is the top foliage layer
in a forest where the trees extend above
surrounding trees.
• Trees in this layer grow and emerge into
direct sunlight reaching heights of 60 to
70m (180-210ft) and can measure up to
5m (15ft) around.
• Animals such as eagles, bats, monkeys,
and snakes live in the emergent layer.
6. What are some
characteristics of the canopy?
• Canopy is formed by trees as tall as 30 m
(100ft.) and 95% of the sunlight is
absorbed by these trees
• The canopy is considered to be the
primary layer of the rain forest.
• The canopy can be split into an upper and
lower canopy with the lower canopy
receiving less of the sunlight.
Canopy of Rainforest
• Epiphytes are plants that use another plant for
support but not for nourishment and are located
on high trees in the canopy.
• Growing on tall trees allows them to reach the
sunlight needed for photosynthesis and to
absorb the water and nutrients that run down the
tree after it rains.
• Most animals that live in the rain forest live in the
canopy because they depend on the abundant
flowers and fruits that grow here.
Epiphytes
7. What are some characteristics
of the understory?
• The understory is the foliage layer that is
beneath and shaded by the main canopy of a
forest.
• There is little light and there are smaller
trees/shrubs adapted to shade living here
• Most plants here do not grow more than 3.5m
tall.
• Forest floor is mostly bare because of the lack of
sunlight
• Herbs have large, flat leaves to capture any
sunlight that does reach the floor
Rainforest floor
8. How are animals adapted to
living in the tropical rain forest?
• Greatest diversity of animals anywhere
• Almost all rain forest animals are
specialists (organisms adapted to exploit a
specific resource in a particular way) to
avoid competition
• They have adapted amazing ways to
capture prey and avoid predators (EX:
Collared anteater, wreathed hornbill) p.159
• Insects use camouflage to avoid predators
and may be shaped like leaves or twigs.
9. What are some threats to the
rain forest?
• Used to cover 20% of
Earth’s surface, today
cover about 7%
• Destruction by
logging, clearing for
agriculture, timber, or
oil exploration
• Exotic pet trading
• This leads to
extinction of
plants/animals and
displacement of the
native people
10. How can you help prevent the
destruction of the rain forest?
• Do not buy rain forest woods such as teak
and mahogany
• Do buy products that support sustainable
use of rain forests such as nuts, fruits,
rubber, coffee
• Support organizations that help preserve
tropical forests
Collecting sap from a rubber
tree
11. What are some characteristics
of the temperate rain forest?
• Occur in N and S America, Australia, New
Zealand
• Cool, humid forest
• Never freezes because ocean waters moderate
the temperature
• High rainfall, moderate temperature
• Olympic National Forest in Washington State
• Dominated by evergreen trees such as Douglas
Fir and Sitka Spruce
12. What are some characteristics
of the temperate deciduous forest?
• Trees shed leaves each fall
• Generally occur between 30° and 50°
North latitude
• Can have extreme seasonal variations
• 4-6 month growing season
• Moist (30-50in rain per year) (75-125cm)
• Very rich soil
TEMPERATE DECIDUOUS
FORESTS
Temperate Deciduous Forest
13. How are plants adapted to
living in the temperate deciduous
forest?
• Plants grow in layers
• Canopy is dominated by tall trees (maple, oak,
birch)
• Small trees, shrubs and bushes in understory
• More light reaches the floor here than in the rain
forest so this has more plants (ferns, mosses,
herbs)
• Adapted to survive seasonal changes (EX: trees
shed leaves in winter when H2O is locked up in
ice; herb seeds, bulbs, rhizomes become
dormant in winter)
14. How are animals adapted to
living in the temperate deciduous
forest?
• There are numerous habitats for animals
(generally organized by layers of
vegetation)
• Many migratory birds
• Animals hibernate (become inactive)
• Insects enter a state of very low metabolic
activity
15. What are some characteristics
of the taiga (Northern Coniferous
Forest)?
• The region of evergreen, coniferous forest below the
arctic and subarctic tundra regions
• Also called the “boreal forest”
• Located in a broad band across the N hemisphere just
below the arctic circle
• Rough terrain
• Long winters (6-10 mo) and little vegetation
• Extremely cold
• Short growing season (50 days in some areas)
• Plant growth enhanced by constant daylight during the
summer
• Most of the precipitation is snow
TAIGA
Taiga
16. How are plants adapted to
living in the taiga?
• Conifers – a tree whose seeds grow in cones
• Most trees here do not shed leaves
• Leaves are narrow and have a waxy coating to retain
water
• Conifers cone shape helps it shed snow whose weight
would otherwise crush it
• Dominant tree species are pine, hemlock, fir, spruce
• Conifer needles are acidic so when they die and fall to
the ground they make the soil acidic
• Because of the acidic soil, the forest floor is mostly bare
• Soil forms slowly here because the climate and acidity
slow decomposition.
17. How are animals adapted to
living in the taiga?
• Lakes and swamps are common so birds
that feed on wetland organisms (insects
and fish) are also common
• Migratory birds
• Underground burrowers (shrew, vole)
• Have moose and snowshoe hares
• Hares change coat color from brown to
white in winter
4-3 GRASSLAND, DESERTS,
AND TUNDRA
1. How does rainfall affect the
characteristics of a biome?
• In climates that have less rainfall, forest biomes
are replaced by savanna, grassland, and
chaparral biomes
• As even less rain falls in these biomes, they
change into desert and tundra biomes.
• As precipitation decreases in an area, the
diversity of the species in the area also
decreases. But, the number of individuals of
each species present may still be very large.
2. What are some characteristics
of tropical savannas?
• An EX. would be the West African Plains
• Occur in parts of Africa, western India, northern
Australia, and parts of South America
• Located in tropics near equator
• Occur inland so get too little rain for many trees
to grow
• Periods of heavy rainfall followed by periods of
drought
• May have grass fires to help restore nutrients to
soil during dry season
TROPICAL SAVANNAS
Tropical Savanna
3. How are plants adapted to living
in the tropical savanna?
• Dominated by grasses, shrubs, and small
trees
• Trees/grasses have large underground
root systems that survive fire and droughts
• Vertical leaves that conserve water
• Trees/shrubs often have thorns/razor
sharp leaves that deter herbivores
4. How are animals adapted to
living in the tropical savanna?
• Have large grazing herbivores that migrate
(follow rain to areas of newly sprouted
grass)
• EX of herbivores: antelopes, giraffe,
elephants, gazelle, rhinos
• EX of predators that live here: cheetahs,
lions, hyenas
• Many give birth only during rainy season
• Herbivores avoid competition for food by
eating vegetation at different heights
5. What are some characteristics
of the temperate grasslands?
• Called prairies in US, steppes in Russia, veldt in
South Africa, and pampas in S America
• Low rainfall so few to no trees are found here
• Periodic droughts
• High temperatures in summer
• Most fertile soil of any biome
• Found inland where there is too little rain for
trees to grow
• Mountains are important in maintaining
grasslands
• Fires common
TEMPERATE GRASSLANDS
Temperate Grassland
6. How are plants adapted to living
in the temperate grasslands?
• Grasses are perennials (survive from year
to year)
• Root systems survive drought and fire,
hold soil in place
• Root depth and grass height vary with
rainfall
• Few trees survive because of drought, fire
and winds
How root depth and height vary
with rainfall:
7. How are animals adapted to
living in the temperate grasslands?
• Adequate food (grasses) for grazers such
as buffalo and pronghorn antelope
• Grazers have large, flat back teeth for
chewing the coarse prairie grass
• Buffalo have thick coats to survive winters;
shed coats in spring
• Badgers, prairie dogs, and owls burrow
underground. This protects them from
predators
8. What are some threats to the
grasslands?
• Cultivation – grain
crops that have
replaced native
grasses contribute to
more soil erosion
• Overgrazing – leads
to erosion
• Constant use can
change the fruitful
grasslands into
desert-like biomes
9. What is the chaparral?
• A type of temperate woodland biome with
vegetation that includes broad leafed evergreen
shrubs.
• Hot, dry summers and mild, wet winters (slight
variations in seasonal temps)
• Located in mid-latitudes, 30°N and S of the
equator
• Located mostly in coastal areas that have
Mediterranean climates (moderately dry, coastal
with little or no rain in summer)
• Similar to desert but chaparral has more
vegetation
10. How are plants adapted to the
chaparral?
• Mostly low-lying evergreen shrubs and small
trees that grow in dense patches (include
chamise, manzanita, scrub oak, and herbs like
sage and bay)
• Plants have small, leathery leaves that resist
water loss
• Leaves contain oils that promote burning. This
allows natural fires to destroy competing trees
• Well adapted to fire and can resprout from small
bits of surviving plant tissue
11. How are animals adapted to
the chaparral?
• Camouflaged (quail, lizards, chipmunks,
and mule deer)
• Adapted to seasonal differences in food
12. What are some threats to the
chaparral?
• Development by humans
13. Where is the chaparral in the
US?
• California
14. What are some characteristics
of the desert?
• Less than 10 in. rain per year (25cm)
• Soil is rich in minerals but poor in organic matter
DESERTS
Desert
15. How are plants adapted to
living in the desert?
• Conserve water
• Fleshy stems and leaves store water
(succulents)
• Waxy coating to prevent water loss
• Cactus spines deter herbivores that would feed
on plants
• Store water in underground bulbs
• Roots are shallow to get any water available and
often contain toxins that prevent other plants
from growing nearby
• Drought resistant plants (can survive in light or
sporadic rainfall)
• Some escape drought by dying and dropping
seeds that stay dormant until the next rainfall
Deserts of the US
16. How are animals adapted to
living in the desert?
• Reptiles (Gila monster and rattlesnakes)
have dry/scaly skin to prevent water loss
• Amphibians estivate (spadefoot toad)
(bury themselves in ground and sleep
through dry season)
• Most desert animals are at least partly
nocturnal (active at night)
• Desert insects and spiders are covered
with thick body armor that helps retain
water
17. What are some threats to the
desert?
• Residential
development
• Off road and all
terrain vehicles kill
desert vegetation
18. What are some characteristics
of the tundra?
•
•
•
•
No trees
Grasses and tough shrubs that grow in the frozen soil
Located north of the Arctic Circle
Very short, cool summers (only top few inches of soil
thaws)
• Permafrost – permanently frozen soil
• Because permafrost is impermeable, the tundra become
dotted with bogs and swamps when top layer of soil
thaws
• Swamps/bogs attract mosquitoes/blackflies in the
summer
TUNDRA
Tundra
19. How are plants adapted to
living in the tundra?
• Mosses and lichens grow here (do not need
soil)
• Where soil exists, plants have wide, shallow
roots that anchor them against arctic winds
• Flowering plants are tiny
• Plants grow flat and trail along the ground to
avoid wind and to absorb heat from sunlit soil
• Woody plants and perennials have evolved
dwarf forms that grow flat along the ground
20. How are animals adapted to
living in the tundra?
• Migratory birds and caribou
• Predators such as wolves prey on the
migratory caribou, moose, and smaller
animals
• Rodents burrow underground but are still
active
• Arctic fox – changes color for camouflage
• Winter animals are very insulated (EX:
musk ox)
21. What are some threats to the
tundra?
• One of the most fragile
biomes on earth
• Food chains are simple
and easily disrupted
• Land is easily damaged
and slow to recover
• Oil exploration (EX:
Prudhoe Bay in northern
Alaska)
• Pollution caused by spills
or leaks of oil and other
toxic materials may
poison food and water
here