BIOMES CHAPTER 4 SECTION 3 SC B6 STUDENTS

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