Chapter 6
Biomes
Biome
 Large
region characterized by a specific
type of climate and certain types of plants
and animal communities
 Each
biome is made up of many individual
ecosystems
Biomes are described by their vegetation because
plants that grow in an area determine the other
organisms that live there.
Plants have specialized structures or adaptations
that allow them to survive in a particular biome.
 Ex: 1. Desert plants like cactus- large cuticle, no
leaves
2. Tundra plants are short from lack of water
Climate

Main factor in determining what plants can grow in
a particular area.

Climate refers to temp, precipitation, humidity,
and wind in an area over a long period of time.
As water and temperature increase,
vegetation becomes higher and denser
Biomes also vary with latitude and
altitude

Latitude- the distance north or south of the
equator and it is measured in
degrees

Altitude- the height of an object above sea level

Climate gets colder as latitude and altitude
increase
The temperate region of the world, between 30 and 60
degrees north latitude and 30 and 60 degrees south latitude
is where most of the food in the world is grown.
Forest Biomes

most widespread and most diverse biomes

Forests exist where temps are mild to hot and rainfall is
plentiful

3 main types of forest biomes
1. Tropical Forest
2. Temperate Forest
3. Coniferous Forest
1. Tropical Rain Forest
 located
in a belt around the Earth near the
equator
 help
regulate world climate
 Play
a vital role in the N, O, and C cycles
 Enormous
amount of biodiversity, only 7% of
the land but 50% of all plant and animal
species
Tropical Rain Forest
 Always
humid and warm
 Get
about 200 to 450 cm of rain a year
 Get
sunlight year round
 Very
poor soil, nutrients locked up in plants
 Runoff
from Rainforests is often as pure as
distilled water
Layers of the Rain Forest

1. Emergent layer- consists of the tallest trees 60-70
m in height.

Trees in this layer grow and emerge in direct sunlight.
Eagles, monkeys, bats and snakes live here.

2. Upper Canopy layer- Trees growing up to 30 m tall.
Forms a dense layer that absorbs up to 95 % of the
sunlight.
Layers of the Rain Forest

3. Lower Canopy layer- receives less light than the upper
canopy.

Epiphytes live here. They live off of other trees.

Orchids and mistletoe are examples.

Most animals that live in the rainforest live in the upper and
lower canopy.

4. Understory- Found underneath the canopy. Very little light
reaches here.

Plants here grow only up to 3.5 m tall. Many have large flat
leaves.
Threats to the Rain Forests
 We
lose 100 acres of rain forest every minute
of every day to:
•
Logging
•
Agriculture
•
Oil exploration
•
Exotic pet trading
2. Temperate Rain Forests
•
Occurs in North America, Australia, and
New Zealand
•
Large amounts of precipitation, high
humidity and moderate temps
•
Trees are covered in mosses
•
Forest floor is covered in ferns
•
Sitka spruce and Douglas fir can reach
90m tall (270ft)
Douglas Fir
Sitka Spruce
3. Temperate Deciduous Forest
•
Located between 30 degrees and 50
degrees north latitude
•
Trees have broad flat leaves that they drop
each fall
•
Winter temperatures often drop below
freezing, meaning little water for plants
•
Receives 75-125 cm of precipitation
annually
Temperate Deciduous Forest
•
Rich deep soils due to fallen leaves
•
Tall trees like oak, maple, birch are the
top layer with smaller trees and shrubs
covering the understory
•
More light reaches the forest floor than in
rain forests so more mosses, ferns and herbs
grow here
4. Taiga- AKA- Boreal Forest AKA- Northern
Coniferous Forest

• Found in the northern hemisphere just below the
Arctic circle

• Winters are long (6-10 months) with temps below
freezing

• Growing season in summer may be as short as 50
days

• Forest floor has few plants because of the acidic
pine needles

•
Soil forms slowly because decomposition is slow
Tropical Grasslands
•
Called Savannas
•
Located in tropical and subtropical areas
near the equator and between tropical
rainforests and desert biomes
•
Contain grasses, scattered trees and shrubs
•
Large variety of grazing animals and
predators
•
Receive little precipitation
Tropical Grasslands

•
Have a wet and a dry season

• Grass fires sweep through and return nutrients to
the soil

• Plants have large horizontal root systems to help
obtain water during the dry season

•

• Animals include: elephants, gazelles, rhinos,
giraffes all of which are different heights to reduce
competition
Some trees lose their leaves to help retain water
Temperate Grasslands
•
Dominated by grasses and has very
few trees
 • Only receive a moderate amount of
rainfall (50-88 cm a year)
 • Most fertile soil of any biome
 • Many have been replaced with crops,
farms and grazing land
Temperate Grasslands
•
Few natural grasslands remain
 • Found in the interior of continents
where there is too little rain for trees
 • Found in North American, Russian
steppes, and in South America
3 types of temperate grassland
 *(determined
by the rainfall and vegetation
that grows there)
 1.
Short grass prairie (about 25 cm rain per
year)
 2.
Mixed or middle grass prairie (about 50 cm
rain per year)
 3.
Tall grass prairie ( up to 88 cm rain per
year)
Short Grass Prairie
Mixed Grass Prairie
Big Blue Stem Grass 6 ft tall
Tall Grass Prairie
Animals

•
Pronghorn

•
Bison,

•
Badgers

•
Prairie dogs

• Owls and
hawks
Chaparral
•
Temperate woodland biome
•
Dominated by broad-leafed evergreen
shrubs than by evergreen trees
•
Located primarily in coastal areas that
have Mediterranean climates (30 degrees
North or South of Equator)
•
Common plants- scrub oak, olive trees,
sage, manzanita
Chaparral
•
Most leaves have oils that promote burning
•
Most plants here can resprout from small bits
of surviving plant tissue
•
Animals include- quail, lizards, chipmunks
and mule deer
•
The greatest threat to this biome is human
development, because they are near the ocean
and have a mild climate
Deserts
•
Driest places on Earth
•
Less than 25 cm rain a year
•
Little to no vegetation
•
Plants found there are called succulents
•
Some animals like toads survive the
summers by estivating
•
Most animals are also nocturnal
Tundra

•
Located primarily north of the arctic circle

•
Most precipitation remains frozen most of the year

•
Soil supports tough grasses and shrubs

•
Mosses and lichens are common

• Plants have wide shallow root because of the
permafrost

• Animals include migratory birds that go their to
breed, caribou, wolves, musk ox, deer, moose
Tundra
•
Tundra is one of the most fragile
biomes
 o Food chains are simple and easily
disrupted
 o Land is easily damage and slow to
recover
 o Oil exploration