Transcript What is a Biome?

Chapter 6-Biomes
Section 6-1: What is a Biome?
Open to p. 153
Define “biome”
Give at least 3 examples of biomes you are
familiar with
What is a biome?
Major type of ecosystem with distinctive
temperature, rainfall, and organisms
Either terrestrial (land) or aquatic (water)
Many ecosystems within a biome
How are Biomes Described?
Refer to p. 153 to describe how biomes are
described and why in your notes.
How are Biomes Described?
By vegetation
Plants that grow in a certain region are the
most noticeable characteristics of that
region
– Plants in each region have adaptation that allow
them to survive there
• Size, shape, color
• Examples: tundra plants are shorter because not
enough water to support a tall plant, desert plants
have waxy structures rather than leaves to conserve
water
Plants determine what other organisms will
live there
Biomes and Climate
Climate: weather conditions such as
temperature, precipitation, and humidity
over a long period of time.
How do you think latitude and altitude
affect biomes?
Latitude and Altitude
Latitude: distance north or south of the
equator
Altitude: height of an object above sea level
How does climate change when you increase
latitude or altitude? (read paragraph on p. 155)
Section 6-2: Forest Biomes
Read the introduction on p. 156 and get
inspired to learn about forests!!!!
4 Forest Biomes
Tropical Rain Forests
Temperate Rain Forests
Temperate Deciduous Forests
Taiga
Rain Forests
Tropical zones – near
equator (constant temps)
long growing season
constant warm temps
200-450 cm of rain per
year
Biome with dense canopy
of evergreen, broadleaf
trees
Most diverse land biome
Keeps Earth’s climate
regulated
Rain forest biodiversity
Contains 70 % of all terrestrial (land)
species on earth
Covers only 6 % of earth’s land surface
Holds 50% of earth’s land biomass
Rainforest Nutrients
Organisms contain the nutrients, not the soil
Refer to p. 157 to explain why
Rainforest Structure
Based on many different
species of trees
Canopy – top of forest, leafy
tops of trees 50-60 m tall,
captures 99% of direct sunlight
Under and Lower Canopy –
filtered sunlight
Understory
Forest floor – sparse vegetation
due to lack of light and
nutrients
– Rapid decomposition of dead
things recycles nutrients quickly
back into the trees making soil
nutrient poor
Rainforest organisms
Trees have wide bases
and shallow roots to take
advantage of the thin
topsoil
– Buttresses – ridges at the
base of tree trunk
Epiphytes – plants like
orchids that live entirely
on the tree trunk or limbs
Arboreal organisms – live
in the trees, rarely touch
the ground
Why is there so much diversity in the
rainforest?
High plant diversity = high animal diversity
Wide variety of habitats exist at different
levels of the forest
Many specialized adaptations
Threats to the rainforest
Deforestation – rainforests once covered 10% of
earth’s surface, now only 6%
Logged for export, farm land, grazing land, living
space
Infertility of soil causes it to only be useful to
farmers for a short time and more land must be
cleared
Slow regeneration – hundreds to thousands of
years
Temperate Rain Forests
North America, Australia, and New Zealand
– The Pacific Northwest in North America
High precipitation, high humidity, but
moderate temperatures
Ocean prevents freezing and high
precipitation keeps humid
Temperate Deciduous Forests
Read description on p. 162
Temperate Deciduous
Forests
Forests whose trees lose
their leaves in the fall
In temperate zones with
well defined seasons
Wide temp range -30 deg
C to 30 deg C
50 – 300 cm precipitation
per year
Trees go through growth
season and dormant
season
– Loss of leaves in fall helps
tree conserve water in
winter
Plants of the Deciduous
Forest
Species more varied than in
coniferous forest
3 Distinct vegetation layers
– Canopy – highest layer, upper
branches and leaves of tall
trees, captures most of the
sunlight
– Understory – layer of young
trees and small trees – shrubs
– Forest floor – mosses, ferns,
decaying matter and organisms
• Humus – deep rich, layer of
topsoil with organic matter
(mostly dead leaves)
Animals of the Deciduous Forests
Are adapted to the use of forest plants for
food and shelter
– Squirrels eat nuts and seeds on treetops
– Deer eat leaves from trees and shrubs
Most birds are migratory
– Cannot survive harsh winters
– Some do not migrate and reduce activity to
preserve energy in winter
Human impact on deciduous forests
Once covered eastern US,
Europe, Asia
Deforestation for farms, orchard,
and urban development (cities)
Logging for hardwood and fuel
Ecosystem is slow to regenerate
when replanted
Taiga
Where do you think the taiga biome is
located?
What do you think this area looks and feels
like?
Taiga (pp. 163-164)
Northern coniferous forest just below the
Arctic Circle
Plant growth abundant in summer because
of nearly constant daylight and more
precipitation
Tree trunks look bare and dead, but they
look alive when you look up at their green
tops
Plants of the Taiga
Conifers: needle-like leaves and seeds
found in cones
– Waxy leaves with low surface area retain
moisture
– Cones-like shape prevents snow build-up
– Acidic leaves dropping on the soil prevent other
plants from growing
Animals of the Taiga
Lakes and swamps with aquatic organisms
attract birds in summer (they migrate south
in winter)
Some organisms hibernate by burrowing
(mice)
Snowshoe hares avoid predation by
shedding fur to change color with the
seasons
Section 6-3: Grassland, Desert,
and Tundra Biomes
Savannas
Tropical and sub-tropical grasslands ranging
from dry scrublands to wet, open woodland
In Asia and Africa and South America
Savanna climate
Short Rainy seasons (3 months in Africa)
– Up to 150 cm of rain per year
– Most during heavy thunderstorms
Long seasons of drought, so plants are small
Savanna vegetation
Must be resistant to drought, fire, and grazing
Runners – long horizontal stems above ground
that aid in reproduction – spread quickly
Rhizomes – horizontal roots underground that
are protected from fire
Tufts – large clumps of tall, coarse grasses
Trees and shrubs have thorns or sharp leaves to
protect from being eaten
Most vegetation grows rapidly but die down to
ground in winter
Savanna animals
Concentrated around watering
holes
Vertical feeding patterns –
animals eat vegetation at
different heights
– Allows for more animals to
survive on limited resources
– Decreases competition for
food
Migrating animals – migrate to
water rather than away from
temperature
Lions, cheetahs, elephants,
giraffe, wildebeest, zebras,
antelope, etc.
Temperate Grasslands
An ecosystem where there is more water (moderate rainfall)
than in the desert but not enough to support a forest
Located in Africa, central Asia, North America, South
America, Australia
Begin at the desert edges
America’s Heartland – central US
Grassland climate
A little more rain than the desert,
enough to enable grasses to grow
Hot, dry summers
In North America, the height of
plants increases as you move
eastward away from the Rockies
because of increasing amounts of
precipitation (most rainfall is over
the mountains)
Grassland organisms
Vegetation = grasses most common
Rainfall = limiting factor
Animals = grazing herbivores, prairie dogs, worms,
insects
– Predators of N. America = coyotes, foxes, birds of prey,
snakes
Importance of grassland fires
Sparked by lightning
Occasional grassfires destroy trees and
shrubs
Grasses survive because most of their mass
is below ground
Fires remove the organisms that compete
with grasses for resources
Effects of the amount of rainfall
Rainfall determines size of grasses
– More rain = taller grasses
Rainy season / dry season
Precipitation increases as you move
eastward in the United States
Most vegetation is drought-resistant
Adaptations of grassland animals
Speed of grazing herds like the antelope =
escape from predators
Nocturnal animals stay in burrow
underground during day to avoid heat and
predators
Chaparral (p. 168)
Temperate shrubland biome
Mediterranean climate: moderately dry,
coastal, little to no rain in summer
See p. 169 for map of locations: in US, the
HOLLYWOOD sign and the old western
movies show chaparral
Organisms of the Chaparral
Plants: low-lying, evergreen shrubs that
grow in dense patches
– Small leathery leaves to retain water
– Oils to promote burning to destroy the trees that
compete for light and space
– Can resprout after fires
Animals: camoflodge (quail, lizards,
chipmunks, mule dear have brownish-gray
color)
Threats to the Chaparral
Human development
– A lot of sun so people want to live and work in
chaparral biomes
Deserts
Located at Tropic of cancer and
Tropic of capricorn
Often located near mountains
which block rainfall so very little
rainfall
Very little biomass (plants and
animals)
Soils rich in minerals but poor in
organic matter (few organisms)
Pavement – exposed when wind
blows away top layer of sand –
desert floor composed of rock
particles and hard baked sand
Extreme temperature changes
daily
Very diverse: 1
thing in
common=the
driest places in
the world
Types of deserts
Cool and hot
Results from differences in altitude and latitude
Cool = Sierra Nevada and Rocky Mountains
Hot = California, Texas, Arizona, New Mexico
Desert organisms
Adapted to survive
extreme temperatures
and lack of water
– Jack rabbit – ears
release heat
– Camel – water storage
– Cacti -water retaining
leaves, roots barely
penetrate the soil
(known as succulents)
Desert plants
Able to absorb water
from deep underground
Small leaves to reduce
water loss through
transpiration – cactus
needles
Succulents – thick water
filled tissue – cacti and
aloe vera
Desert animals
Wide variety of
species
Most water obtained
from food, not by
drinking water
Adaptations to reduce
water loss and
survive the heat
Nocturnal – active at
night when temp is
cool
Big ears – release
heat
The Tundra
Located in northern
hemisphere in Alaska,
Canada, Greenland,
Iceland, Scandinavia,
and Russia
Largest biome = 10% of
earth’s surface
Smallest variety of
organisms than any
other biome
Fragile ecosystem due
to lack of biodiversity
Tundra Climate
Very little precipitation <25 cm
per year
– Ice and snow
Very cold, usually 10 degrees C
or below
Temp is a limiting factor
Permafrost – frozen soil below
the active zone – insulated by
mosses and grasses – does not
soak in water creating bogs and
marshes and insect breeding
grounds
Tundra plants
Summer growing season =
60 days
Mosses, shrubs, grasses,
small wildflowers
Shallow roots, low to the
warm ground
Trees look more like shrubs,
< 1m tall
Tundra animals
Most are seasonal migrators i.e. Birds
Few predators
Birds feed on insects, migrating predators feed on
birds
Small herbivores but no reptiles or amphibians
Tundra animals adaptations for survival
Thick coats
Wide hooves – caribou – easier to walk through snow or
mud
Artic fox buries food in permafrost to eat later in the winter
Larger bodies with small limbs and ears to conserve heat
Threats to the tundra
Air pollution – kills lichen with is a major
food source for caribou herds
Building of structures that intefere with
migratory routes
Trans-Alaskan Oil Pipeline