Transcript Science - Biomes

Biomes
Biome
• a large group of ecosystems
that share the same type of
climax community
2 Types of Biomes
Terrestrial (land) Biomes
Aquatic (water) Biomes
marine (salt water)
freshwater biomes
6 Major Terrestrial (Land) Biomes
• terrestrial biomes are defined by
their latitude, altitude, and
precipitation
Terrestrial Biomes
•
•
•
•
•
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tundra
taiga
dessert
grasslands
temperate forest
tropical rain forest
Tundra
• treeless area around the poles
• temperatures rise above freezing
only for very short periods of time,
about 12 cm precipitation annually
Tundra
• soil is lacking in nutrients; topsoil is thin little decay occurs
• soil supports only shallow-rooted grasses
and small plants
• short growing season-limiting factor for life
• contains permafrost - layer of permanently
frozen ground
Taiga
•called northern conifer forest
•climate is harsh - long, severe winters, short,
mild summers, 35-40 cm precipitation annually
•permafrost is usually absent
•found in Canada, Northern Europe, Asia
Taiga
Flora/Fauna:
• lichens, mosses, grasses, dwarf
shrubs, cushion plants, mosquitoes,
other biting insects, lemming, weasels,
arctic foxes, snowshoe hares, snowy
owls, hawks, musk-oxen, caribou,
reindeer
Taiga
•topsoil is acidic and
poor in minerals
Example Organisms:
mixed pine, fir,
hemlock, & spruce
trees, more large
species of animalscaribou, moose, lynx
Desert
•Driest of the biomes, less than 25 cm of
precipitation annually
•Located south of the taiga
•Atacama Desert in Chile – world’s driest place
Desert
•an arid
region with
sparse to
almost
nonexistent
plant life
•desert plants sometimes have spines, thorns, or
poisons that act to discourage herbivores
•example organisms - shrub, mesquite trees,
cacti, kangaroo rat, pronghorn antelopes, foxes,
coyotes, hawks, owls, roadrunners, snakes,
lizards, scorpions
Grassland
•receives
between 25 and
75 cm of
precipitation
annually
• soils have considerable humus content
• usually experience a dry season where
insufficient water exists to support forests
–example organisms - more than 100 different
species per acre, large herds of grazing
animals, bison, buffalo, wolves, coyotes,
prairie dogs, foxes, ferrets, birds, insects,
reptiles, tortoises, lizards, snakes
•large communities covered with grasses and
similar small plants
•known as prairies (U.S., Canada, & Australia),
steppes (Russia), savanna (Africa), pampas
(Argentina)
•called the breadbaskets of the world-ideal for
growing grains (oats, rye, wheat)
•occupies more
area than any
other terrestrial
biome
Grassland
Temperate Forest
– soil consists of top
layer rich in humus
and a deeper layer
of clay
– example organisms
- squirrels, mice,
rabbits, birds, black
bears, deer,
salamanders,
opossums
Temperate Forest
•precipitation ranges from 70-150 cm annually
•deciduous forests - dominated by broadleaved hardwood trees that lose their foliage
annually (deciduous)
Tropical Rain Forest
– most biologically diverse of the terrestrial biomes,
located in the equatorial regions around the world
– uniformly warm (25oC) , wet weather dominated
by lush plant growth, annual rainfall is at least
200cm up to 400 cm, which much of is retained
and recycled by the heavy canopy of leaves
Tropical Rain Forest
• most organisms live in the trees
• more species of reptiles, amphibians, and birds
are found here than any other terrestrial biome
• 3 million species of insects in the tropical rain
forest, butterflies, gorillas, cougars
Nutrients from decay must be absorbed quickly.
Why?
Due the large amount of rain
Precipitation Amounts
precipitation in cm
450
400
400
350
300
250
200
200
150
150
75 70
100
50
0
40 25
12
Tundra
Taiga
Dessert
grasslands
temperate forest
temperatrate forest II
traopical rain forest
tropical rain forest II
1 cm = 0.4 inches
Marine Biomes
• oceans contain the largest amount
of biomass (living material) of any
biome on Earth
• most of this biomass is plankton microscopic organisms that float in
the layers of the photic zone
Water Zones
• photic zone -
more shallow,
sunlit zone
• aphotic zone deeper water
that never
receives sunlight
Mixed Waters
• all waters flow to a sea/ocean
• estuary – coastal body of water
partially surrounded by land
where saltwater and freshwater
mix
Tides
• caused by the gravitational
pull of the sun and moon –
twice a day
• intertidal zone – area
between the high and low tide
lines
Photic Zone
• rainfall washes nutrients from land
into the waters
• high in nutrients and abundant in life
• plankton – small organisms that
live in waters of the photic zone –
base of all aquatic food chains
Aphotic Zone
• intense pressure
• no light
• animals are adapted for darkness
and scarcity of food
Freshwater Biome
 ponds,
rivers, and lakes
 temperature varies with depth –
abiotic factor that limits the kind of
organisms that can survive in a
deep lake
 light also is a limiting abiotic factor