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BIOMES
CHAPTER 4 SECTION 3
SC B-6: STUDENTS WILL
DEMONSTRATE AN UNDERSTANDING
OF THE INTERRELATIONSHIPS
AMONG ORGANISMS & THE BIOTIC &
ABIOTIC COMPONENTS OF THEIR
ENVIRONMENT
Biomes
major life zones characterized by vegetation type (in
terrestrial biomes) or by the physical environment
(in aquatic biomes)
Climograph
plot of annual mean
temperature &
precipitation in a
particular region
Climographs
show that temp & precipitation are correlated with
biomes
because other factors also play a role in biome
location: biomes can overlap
Climograph for Some Major Biomes
General Features of Terrestrial Biomes
most named for major physical or climatic features &
for their predominant vegetation
each biome also characterized by:
microorganisms
fungi
animals
all adapted to that particular environment
Biome Species Composition
varies w/in each biome
ex: eastern part of one large lake may have
different water bird than western portion
Tropical Forest
Distribution: equatorial & subequatorial
Precipitation:
Tropical
Rainforest: constant, 200 -400 cm/yr
Tropical Dry Forest: seasonal, 150 – 200 cm/yr
Temperature:
high all yr, average 25 – 29°C , little seasonal
variation
Tropical Forest
Tropical Forest: Plants
vertically layered
intense competition for light
Tropical Forest Plants
Tropical Dry Forest
Tropical Rainforest
see all layers, some
with 2 layers of
subcanopy trees
broadleaf evergreen
trees dominate
epiphytes (air
plants) & orchids
typically cover trees
see fewer layers
drop leaves during
dry season
commonly have
thorny shrubs &
succulent plants
Tropical Forest: Animals
millions of species
5 – 30 million undiscovered species of insects,
spiders, other arthropods
highest animal diversity than anywhere else on Earth
all adapted to vertically layered environment
DESERT
Distribution:
occur in bands near 30° N & S latitude or in
interior of continents
Precipitation:
low & variable; <30 cm/yr
Temperature :
variable seasonally & daily
hot desert: max T may > 50°C
dry desert: low T may < -30°C
Deserts
Desert Plants
see low, widely scattered vegetation
see more bare ground than other terrestrial
biomes
succulents
cacti
euphorbs
deeply rooted shrubs & herbs
grow during brief rainy periods
Desert Plants
Adaptations:
heat & desiccation tolerance
water storage
reduced leaf surface area
CAM photosynthesis
physical defenses:
spines
chemical defenses:
toxins in leaves of shrubs
Desert Animals
Common animals:
Snakes
Lizards
Scorpions
Ants
Beetles
Birds: migratory & resident
seed-eating Rodents
Desert Animal Adaptations
many species are nocturnal
water conserved in variety of ways:
only water some get is by metabolizing
carbohydrates water + carbon dioxide
SAVANNA
Distribution:
equatorial & subequatorial
Precipitation:
seasonal rainfall 30 – 50 cm/yr
dry season can last 8 – 9 months
Temperature :
warm year-round: 24 – 29 °C
more seasonal variation than tropical forests
Savanna Distribution
Savanna
Savanna Animals
dominant herbivores are insects
especially termites
large herbivores migrate toward thicker vegetation &
watering holes during dry season
Chaparral
also called
mattoral (Spain & Chile)
garigue & maquis (southern France)
fynbos (South Africa)
Chaparral
Distribution:
midlatitude coastal regions
Precipitation:
highly seasonal (rainy winters, dry summers)
averages 30 – 50 cm/yr
Temperature :
fall, winter, spring are cool (10 – 12°C)
summer can get > 40°C
Chaparral Distribution
Chaparral
Chaparral Plants
dominated by shrubs, small trees, variety of grasses
& herbs
plant diversity high though some species found only
in very limited areas
adaptations to:
drought: tough evergreen leaves
fire:
herb seeds only germinate after hot fire
roots are fire resistant (plants re-sprout quickly)
Chaparral Animals
natives include:
browsers (deer,
goats)
high diversity of
small mammals
many amphibians,
birds, reptiles,
insects
Temperate Grassland
also called:
veldts (South Africa)
puszta (Hungary)
pampas (Argentina & Uruguay)
steppes (Russia)
plains & prairies (North America)
Temperate Grasslands
Temperate Grassland
Precipitation:
highly seasonal: dry winters/wet summers
averages vary between 30 – 100 cm/yr
periodic drought is common
Temperature :
winters cold (< -10°C)
summers moderately hot ( 30°C)
Temperate Grasslands
Temperate Grasslands: Plants
dominant plants are grasses & forbs
some grasses 2 m high
many adapted to survive periodic drought & fires
grazing by herbivores helps prevent establishment of
woody plants
Temperate Grasslands: Animals
native mammals
large: bison, wild horses
small burrowers: prairie dogs
Northern Coniferous Forest
aka: taiga
Distribution:
broad band across northern North America &
Eurasia to edge of arctic tundra
Precipitation:
30 – 70 cm/yr
periodic droughts are common
Temperature :
winters cold (-50°C in Siberia)
summers usually >20°C
Northern Coniferous Forest
aka: taiga
Distribution:
broad band across northern North America &
Eurasia to edge of arctic tundra
Precipitation:
30 – 70 cm/yr
periodic droughts are common
Temperature :
winters cold (-50°C in Siberia)
summers usually >20°C
Northern Coniferous Forest
Northern Coniferous Forest: Plants
Northern Coniferous Forest: Animals
Birds: residents & summer migrants
insects occasionally kill large tracts of trees
Mammals:
Moose
Brown Bear
Siberian Tiger
Temperate Broadleaf Forest
Distribution
mainly in midlatitudes of northern hemisphere
smaller areas in Chile, South Africa, Australia,
New Zealand
Temperate Broadleaf Forest
Precipitation:
70 to > 200 cm/yr (includes snow)
all seasons have precipitation
Temperature :
winter averages ~ 0°C
summers hot & humid/ up to 35°C
Temperate Broadleaf Forest
Temperate Broadleaf Forest: Plants
mature forest has distinct vertical layers including a
closed canopy
dominant plants in North America are deciduous
trees
adaptation: drop leaves as weather gets colder:
uptake of water by roots not feasible when soil
frozen
dominant plant in Australia: Eucalyptus
Temperate Broadleaf Forest: Animals
mammals, birds, insects make use of vertical layers
many mammals hibernate in winter
many birds (and some butterflies) migrate south
Tundra
Distribution:
covers arctic: 20% Earth’s land surface
tops of high mountains
Precipitation:
20 – 60 cm/yr in arctic tundra
>100 cm/yr alpine tundra
Temperature:
winter averages < -30°C
summer averages < 10°C
Tundra
Tundra: Plants
mostly herbaceous:
mosses, grasses,
forbs + dwarf shrubs
& trees, lichens
permafrost (frozen
ground year round)
prohibits growth of
plant roots
Tundra: Animals
Birds: migratory, arriving for nesting in summer
Mammals:
Residents: musk ox
Migrators: caribou, reindeer
Predators: bears, wolves, foxes