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