Transcript Fig. 50.25f - Greater Atlanta Christian Schools

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TERRESTRIAL BIOMES
CAUSES OF BIOMES
DESERT
PRECIPITATION
TEMPERATURE
AND
PRECIPITATION
GRASSLAND
TEMPERATE
DECIDUOUS
FOREST
RAINFOREST
TEMPERATURE
TUNDRA
TAIGA
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• Temperate deciduous forests contain dense
stands of trees and have very cold winters and
hot summers. The trees lose
leaves and go
dormant in winter.
• This biome
includes a large
variety of plants
and animals.
• Humans have
logged many of
these forests
around the world.
Fig. 50.25f
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
TEMPORATE
DECIDUOUS FOREST
• North America
•
Rainfall mean 30-50 inches,
falls throughout the year
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• Temperate forests grow throughout midlatitude regions with sufficient moisture
to support growth of large, broad-leafed
deciduous trees.
 Occur in Eastern U.S., Middle Europe
and E. Asia.
 Temperatures range from very cold in
winter to very hot in summers, with a 5 to
6 month growing season.
 Precipitation is fairly high and evenly
distributed throughout the year.
 Soil is rich in nutrients
• Several layers of vegetation
including herbs, shrubs and one
or two strata of trees (species
composition varies widely) are
present.
• Variety and abundance of
food and habitat supports a
rich diversity of animal life.
• Dominant plants—broad leaf
trees
•
• Animal Adjustments—adapted
structurally, functionally, and
behaviorally to live or under
trees.
• Claws or sucking discs for
climbing
• Parachutes and bushy tails of
squirrels
• Hearing and voice well
developed.
TUNDRA
• Tundra is at the northern-most
limits of plant growth and at high
altitudes and plant forms are
limited to low, shrubby or matlike vegetation.
• There are two types of tundra:
•Location
• Alpine- Tree line to
perpetual
snowline
• Arctic- North of coniferous
forest
•Arctic Tundra
• Precipitation—10 inches or
less per year
• Temperature - 30 to +50
degrees F
• Frost anytime in North, 60
day frost free in South
•Arctic tundra encircles the North Pole and is
very cold with little light for long periods.
•·
Brief warm summers are marked by
nearly 24 hours of daylight.
•·
Some areas are characterized by
permafrost (permanently frozen ground),
which contributes to the absence of taller
plant forms.
•·
Soil is continuously saturated, further
restricting plant forms.
•·
Dwarf perennial shrubs, sedges, grasses,
mosses and lichens are common.
• Most are perennials – too short
growing season to produce seeds
• Vegetative reproduction
important
• Tundra contains low growing plants.
– The climate is windy and cold which
causes a short growing season.
– A layer of permafrost is found below 1
meter and does not thaw, which
prevents root growth; not many animals
live in tundra biomes.
– There are two types, arctic, which is
found in areas of Alaska and the Arctic
circle, and alpine, which is found on very
high mountaintops.
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Fig. 50.25h
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Permafrost- ground frozen 1 foot
down all year
Soil wet and soggy in summer
Uplifting – thawing
Lakes frozen 9 months – oxygen
disappears
Photoperiod – no light in winter 24
hour light in summer
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www.saskschools.ca/~gregory/ arctic/animals
www.saskschools.ca/~gregory/ arctic/animals
www.nationalgeographic.com
www.saskschools.ca/~gregory/ arctic/animals
www.saskschools.ca/~gregory/ arctic/animals
• Many animals are migratory and
exhibit adaptations to the cold. Large
animals are herbivores like musk oxen
and caribou. Smaller animals are
lemmings, arctic fox and snow owl.
• Alpine Tundra
• Alpine tundra occurs at high elevations in all
latitudes
• —mountain peak are islands to some
organisms
• Lacks permafrost – normal photoperiod
• Soil thin and unstable
• Great daily temperature flux (58 degree
difference between night and day)
• North slopes colder than South, some frost
free period
people.clemson.edu/.../habitats/ tundra1/tundra1
www.unc.edu/depts/geog/lcsal/ Images/gnp_drawing.gif
www.rmnp.com/Flowers
www.explore-rocky.com
/
• Precipitation and humidity high
• Rapid streams, strong winds, high
light intensity
• Low barometric pressure, low
oxygen concentration
• Vegetation—sedges, rushes,
lichens, mosses, shrubs, grasses,
flowering herbs
• --small stunted, adapted to resist
desiccation, and abrasion from
wind, snow, sand
•Alpine Tundra
Desert
•Desert is characterized by
low precipitation (< 30
cm/year)[ 10” ], not by
temperature: both cold and
hot deserts exist.
• Deserts have low rainfall, and are generally
hot.
• Vegetation is usually sparse, and includes cacti
and succulents.
• Many animals
are nocturnal,
so they can
avoid the heat.
Fig. 50.25c
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• The cycles of growth and reproduction
are keyed to rainfall.
• Scattered scrubs, cacti and
succulents common. Many bloom
abundantly after a rainfall.
• Reptiles and seed eaters such as ants,
birds and rodents are common
• Many live in burrows, are nocturnal or
have other adaptations for conserving
water.
GRASSLAND BIOME
•The veldts of S. Africa, the pusta of
Hungary, the pampas of Uruguay and
Argentina, the steppes of Russia and
the plain and prairies of the U.S. are
examples.
• Occasional fires and drought prevent
encroachment of trees upon the
grassland
· Large grazing mammals and large
carnivores are common.
• Temperate grasslands exhibit seasonal
drought, occasional fires, and are usually
used for grazing and agriculture.
Fig. 50.25e
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mbgnet.mobot.org/sets/grasslnd
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• Covers 42% of Earth’s land area
• Precipitation = 10-40 inches/year
• North American location = Adjacent
to deciduous forest, taiga, and desert
• Big daily temperature fluctuation
• High evaporation rate and periodic
droughts
• Little snow but blizzards are
common
• Fires and grazing important for
maintaining grasses
• East- Tall-grass prairie / 25-30 inches per
year:
– Tall bluegrass, Switch grass, Indian
grass, Corn
• Middle- Mid-grass prairie /15-25” per year:
– Little bluestem, Western wheatgrass,
June grass, Wheat
• West- Short-grass prairie 10-15” per year:
• Buffalo grass, Blue grama grass
Savanna
• Savanna is grassland with scattered
individual trees.
• Covers areas of central S. America,
central and S. Africa and parts of
Australia.
• Generally 3 distinct seasons: cool and
dry, hot and dry, warm and wet, in that
order.
• Frequent
fires inhibit
invasion by
trees to
maintain the
grasses
(wind
pollinated)
and forbs
(often insect
pollinated).
• Large
herbivores
(zebras,
giraffes) and
burrowing
animals are
commonly
most active
in the rainy
season and
many are
nocturnal.
• Savannas are grasslands with scattered
trees, that show distinct seasons,
particularly wet and dry.
– They have many types of plants and animals.
– Fire is an important abiotic factor.
Fig. 50.25b
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Tropical Forest
• Tropical forest is found near the
equator
• where temperature varies little from
approximately 25C
• and the length of daylight varies from
12 hours by less than one hour.
• Tropical forests are close to the equator,
receive high amounts of rainfall (although
this can vary from region to region), and
contain a great variety of plants and
animals.
• The vegetation
is layered, with
the canopy
being one of
the top layers.
Fig. 50.25a
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
• Rainfall is variable. Amount
determines vegetation species in an
area.
 Harbors more plants and animal species
than any other community.
 Competition for light is strong selective
force in plant communities.
 Soils poor due to rapid nutrient
recycling.
 Animals are typically tree-dwellers.
• Destruction of tropical rain forests, occurring
rapidly due to human intervention, may cause
large-scale changes in world climate as well as
destruction of many species.
•More than 90” of
precipitation each year
•Coniferous trees
•Redwoods
•Northern ½ of western coast
of North America
• Coniferous forests are the largest terrestrial biome
on earth.
– They exhibit long cold winters and short wet summers.
– Conifers inhabiting
them are adapted
for the climate.
– Conifer forests
are home to
various animals,
some of which
hibernate.
Fig. 50.25g
Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Located just below tree-line on Mountains
Pine, Spruce, Fir, Hemlock