BiomesThe biosphere is divided into

region called biomes.A Biomes is a group of

ecosystems that exhibit common environmental

characteristics .

1. Tropical Rain Forest2. Desert3. Temperate Grasslands4. Savannas5. Temperate Deciduous

Forest6. Conifer Forest-Taiga7. Tundra8. Marine9. Freshwater

Earth’s Biomes

Earth’s Biomes

Tropical Rain Forest•High temp•Heavy rainfall•Tall trees that branch at their

tops forming canopies•Very little light reaches the floor•Epiphytes and vines

•Equatorial– 4% of Earth’s land surface– Account for 20% of Earth’s net

carbon fixation

•Most diversity of species of any biome

•Animals:– Birds, reptiles, mammals,

amphibians

Desert

• Hot & dryHot & dry• Less than 10” of rainfall per yearLess than 10” of rainfall per year• Extreme temperature Extreme temperature

fluctuationsfluctuations• Plants:Plants:

– Cactus, sagebrushCactus, sagebrush– CAM plantsCAM plants

• Modification for water storageModification for water storage

• Animals:– Rodents, kangaroo rat, snakes, lizards,

arachnids, insects, and few birds

Temperate Grasslands• Low annual rainfall• Grazing mammals (bison, antelope),

burrowing mammals (prairie dogs & other rodents)

• Warm to hot summers, cold winters, moderate, seasonal prec, fertile soils, fires

• Dominant plants: lush, perennial grasses and herbs, resistant to drought, fire and

• Dominant wildlife: predators (coyotes, badgers, wolves, grizzly bear); herbivores (deer, antelope, rabbits, prairie dogs, bison); birds (hawks, owls, bobwhite), insects (ants and grasshoppers)

• Geographic distribution: central Asia, N.A., Australia, central Europe, upland plateaus of S.A.

Temperate Grasslands

SavannasSavannas• Grasslands with scattered trees• Warm temps, seasonal rainfall,

compact soil, frequent fires due to lightning

• Tropical, less rainfall than rain forest

Savannas• Dominant plants: tall, perennial grasses, drought-

and fire-resistant shrubs and trees• Dominant wildlife: predators (lions, leopards,

cheetahs, hyenas, jackals), herbivores (elephants, giraffes, antelopes, zebras), birds (eagles, ostriches, weaver birds, storks), insects (termites)

• Geographic distribution: large parts of eastern Africa, southern Brazil, northern Australia

Temperate Deciduous Forest• Cold to moderate winters, warm summers, year-Cold to moderate winters, warm summers, year-

round precip, fertile soilround precip, fertile soil– 70-150 cm annual precip70-150 cm annual precip

• Dominant plants: broadleaf deciduous trees, Dominant plants: broadleaf deciduous trees, some conifers, flowering shrubs, herbs, mosses some conifers, flowering shrubs, herbs, mosses and fernsand ferns– Broad-leaved hardwood trees that shed their leaves Broad-leaved hardwood trees that shed their leaves

each yeareach year– Soil has top layer that is rich in humus, deeper layer of Soil has top layer that is rich in humus, deeper layer of

clay. If minerals are not taken up by plants roots, the clay. If minerals are not taken up by plants roots, the minerals get into clay and are trappedminerals get into clay and are trapped

Temperate Deciduous Forest• Dominant wildlife:Dominant wildlife: deer, black bears,

bobcats, nut and acorn feeders, omnivores (raccoons and skunks), songbirds, turkeys

• Geographic distribution:Geographic distribution: eastern U.S., southeastern Canada, most of Europe, parts of Japan, China, and Australia

Conifer Forest-Taiga• Long, cold winters; short, mild summers;

moderate precip; high humidity; acidic, nutrient-poor soil– A little warmer and wetter than tundra, but long,

severe winters and short,mild summers– NO PERMAFROST layer, but decay of evergreen

needles makes soil acidic and mineral-poor

• Dominant Plants: needleleaf coniferous trees, broadleaf deciduous trees; small, berry-bearing shrubs

• Dominant Wildlife: predators like lynx and timberwolves; weasel family; herbivorous mammals (large and small); beavers; migratory songbirds

• Geographic distribution: N.A., Asia, Northern Europe

Conifer Forest-Taiga

Tundra• Strong winds;low precip;short and soggy

summers; long, cold, dark winters; poorly developed soils– Permafrost present – permanently frozen ground

under the topsoil

• Dominant Plants: mosses, lichens, sedges, short grasses (ground-hugging)

Tundra• Dominant wildlife: birds and

mammals that can withstand harshness; migratory waterfowl, shore birds, musk ox, Arctic fox, caribou; small rodents

• Geographic distribution: northern N.A., Asia and Europe– Closest to poles

Aquatic Biomes~Marine~

• Oceans contain the largest amount of living material (biomass) of all of the biomes – but most of them are microscopic orgs!!!

• Since oceans are huge, studied based on light penetration:– --photic zone (shallow, lots of light available)– --aphotic zone (deep, never receive sunlight)

Estuaries and Tidal effects• Estuary – found on coast, partially surrounded

by water; here, salt water and fresh water mix.

• *see variations in SALINITY – salt concentration, so what grows/lives here varies enormously.

Intertidal Zone• Tides – gravitational pull of sun and moon

causes the rise and fall of ocean.• INTERTIDAL ZONE – portion of shoreline

between high and low tide zones• *high levels of sunlight, nutrients,

and oxygen, but low PRODUCTIVITY due to waves and movement

Aquatic Biomes~Fresh waterFresh water~

EX. Lakes, ponds, rivers, streams

• Light penetration still affects productivity – photic zone has high productivity, – aphotic zone has low productivity

• But, bottoms of lakes and ponds have decay taking place (dead orgs drift to bottom, bacteria break them down and form detritus), so importance in CYCLES is enormous…

Earth’s Biomes