CHAPTER 4 SECTION 3SC B-6: STUDENTS WILL

DEMONSTRATE AN UNDERSTANDING OF THE INTERRELATIONSHIPS

AMONG ORGANISMS & THE BIOTIC & ABIOTIC COMPONENTS OF THEIR

ENVIRONMENT

BIOMES

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:microorganismsfungianimalsall 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 & subequatorialPrecipitation:

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 layeredintense competition for light

Tropical Forest Plants

Tropical Rainforest see all layers,

some with 2 layers of subcanopy trees

broadleaf evergreen trees dominate

epiphytes (air plants) & orchids typically cover trees

Tropical Dry Forest see fewer layers drop leaves during

dry season commonly have

thorny shrubs & succulent plants

Tropical Forest: Animals

millions of species5 – 30 million undiscovered species of

insects, spiders, other arthropodshighest animal diversity than anywhere else

on Earthall adapted to vertically layered environment

DESERT

Distribution: occur in bands near 30° N & S latitude or in

interior of continentsPrecipitation:

low & variable; <30 cm/yrTemperature :

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

biomessucculents

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:SnakesLizardsScorpionsAntsBeetlesBirds: migratory & residentseed-eating Rodents

Desert Animal Adaptations

many species are nocturnalwater 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: taigaDistribution:

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: taigaDistribution:

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 migrantsinsects occasionally kill large tracts of treesMammals:

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 wintermany 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