Chapter 3Chapter 3Communities and BiomesCommunities and Biomes

Section 2, Part 2Section 2, Part 2

Terrestrial BiomesTerrestrial Biomes

LatitudeLatitude Position north or south of the equator.Position north or south of the equator. The sun strikes the Earth at different angles at The sun strikes the Earth at different angles at

different latitudes.different latitudes. This determines the climate at each latitude.This determines the climate at each latitude.

Climate includes wind, cloud cover, temperature, Climate includes wind, cloud cover, temperature, humidity, and precipitation.humidity, and precipitation.

Latitude and climate are abiotic factors that Latitude and climate are abiotic factors that affect what organism can survive in an area.affect what organism can survive in an area.

TundraTundra Circles the polar regions.Circles the polar regions. Long summer days and short winter days.Long summer days and short winter days. Temperatures are rarely above freezing.Temperatures are rarely above freezing. Precipitation les than 25 cm per year.Precipitation les than 25 cm per year. Only the top layer of soil thaws during the Only the top layer of soil thaws during the

summer.summer. Under the top layer is a layer of permanently Under the top layer is a layer of permanently

frozen ground called permafrost.frozen ground called permafrost.

TundraTundra Although summer days are long, the growing Although summer days are long, the growing

season is short.season is short. Process of decay is very slow due to cold Process of decay is very slow due to cold

temperatures, so nutrients are poor.temperatures, so nutrients are poor. Combined with poor nutrient content, the Combined with poor nutrient content, the

topsoil is thin, so only shallow-rooted grasses topsoil is thin, so only shallow-rooted grasses and small plants, such as dwarf shrubs and and small plants, such as dwarf shrubs and cushion plants, can grow.cushion plants, can grow.

TundraTundra Mosquitoes and black flies are common Mosquitoes and black flies are common

insects.insects. Lemmings, weasels, arctic foxes, snowshoe Lemmings, weasels, arctic foxes, snowshoe

hares, snowy owls, and hawks are the main hares, snowy owls, and hawks are the main small animals.small animals.

Musk oxen, caribou and reindeer migrate into Musk oxen, caribou and reindeer migrate into the area during the summer months.the area during the summer months.

TaigaTaiga Also called boreal or northern coniferous Also called boreal or northern coniferous

forests.forests. Located just south of the tundra.Located just south of the tundra. Stretches across much of Canada, Northern Stretches across much of Canada, Northern

Europe, and Asia.Europe, and Asia. Forms an almost continuous band of Forms an almost continuous band of

coniferous trees worldwide.coniferous trees worldwide.

TaigaTaiga Warmer and wetter than tundra biomes.Warmer and wetter than tundra biomes. Climatic conditions are harsh with long, severe Climatic conditions are harsh with long, severe

winters and short, mild summers.winters and short, mild summers. 35 to 100 cm of precipitation per year.35 to 100 cm of precipitation per year. Permafrost is usually absent.Permafrost is usually absent. Top soil is acidic and poor in minerals as it Top soil is acidic and poor in minerals as it

develops slowly from decaying coniferous develops slowly from decaying coniferous needles.needles.

TaigaTaiga Common trees are larch, fir, hemlock, and Common trees are larch, fir, hemlock, and

spruce.spruce. When the community is disrupted by fires or When the community is disrupted by fires or

logging, birch, aspen, and other deciduous logging, birch, aspen, and other deciduous trees can colonize the area because the new trees can colonize the area because the new soil conditions are with their tolerance range.soil conditions are with their tolerance range.

TaigaTaiga Animals common in the Taiga include Animals common in the Taiga include

weasels, red squirrels, voles, elk, red deer , weasels, red squirrels, voles, elk, red deer , moose, caribou, lynx, snowshoes hares, and a moose, caribou, lynx, snowshoes hares, and a variety of migratory birds.variety of migratory birds.

DesertDesert Arid region with sparse to almost nonexistent Arid region with sparse to almost nonexistent

plant life.plant life. Driest biome, usually receiving less than 2 cm Driest biome, usually receiving less than 2 cm

of rain annually.of rain annually. Rainfall is the biggest limiting factor.Rainfall is the biggest limiting factor.

DesertDesert Areas receiving higher amounts of rainfall Areas receiving higher amounts of rainfall

form shrub communities which may include form shrub communities which may include drought resistant trees such as mesquite.drought resistant trees such as mesquite.

Areas receiving less rain have scattered plant Areas receiving less rain have scattered plant life and large areas of bare land.life and large areas of bare land.

DesertDesert Desert plants have various adaptations for Desert plants have various adaptations for

living in arid regions.living in arid regions. Cacti have spines, photosynthetic stems, and waxy Cacti have spines, photosynthetic stems, and waxy

coating to help conserve water and discourage coating to help conserve water and discourage herbivores.herbivores.

Some desert plants have leaves that either curl up Some desert plants have leaves that either curl up or fall off during extreme dry spells.or fall off during extreme dry spells.

Many desert plants germinate from seed and grow Many desert plants germinate from seed and grow to maturity in short time periods after sporadic to maturity in short time periods after sporadic rainfall.rainfall.

DesertDesert Many desert animals are small herbivores Many desert animals are small herbivores

which hide during the heat of the day abd which hide during the heat of the day abd forage on plants at night.forage on plants at night.

Other animals include kangaroo rats, coyotes, Other animals include kangaroo rats, coyotes, hawks, owls, roadrunners, snakes, lizards, and hawks, owls, roadrunners, snakes, lizards, and scorpions.scorpions.

GrasslandsGrasslands Also called prairies, steppes, savannas, and Also called prairies, steppes, savannas, and

pampas.pampas. In the United States, grasslands are located in In the United States, grasslands are located in

the central and southwestern states.the central and southwestern states.

GrasslandGrassland Receives between 25 and 75 centimeters of Receives between 25 and 75 centimeters of

precipitation annually, but usually experience precipitation annually, but usually experience a dry season, where insufficient water exists to a dry season, where insufficient water exists to support forests.support forests.

Scattered trees are found throughout with Scattered trees are found throughout with larger groupings of trees near streams and larger groupings of trees near streams and other water sources.other water sources.

GrasslandsGrasslands Large communities covered with rich soil.Large communities covered with rich soil.

Soil has high humus content due to the many Soil has high humus content due to the many grasses which die off during the winter.grasses which die off during the winter.

Grass roots survive through the winter, Grass roots survive through the winter, enlarging every year to form a continuous enlarging every year to form a continuous underground mat called sodunderground mat called sod

GrasslandsGrasslands Higher biological diversity than deserts.Higher biological diversity than deserts. Other plants include oats, rye, wheat, Other plants include oats, rye, wheat,

sunflowers, and a variety of wildflowers.sunflowers, and a variety of wildflowers. Grazing animals include bison, deer, and elk.Grazing animals include bison, deer, and elk. Other animals include jack rabbits, prairie Other animals include jack rabbits, prairie

dogs, foxes, and ferrets.dogs, foxes, and ferrets.

Temperate ForestsTemperate Forests Also called deciduous forests.Also called deciduous forests. Receive 70 to 150 cm of rain annually.Receive 70 to 150 cm of rain annually. Temperatures from below freezing in the Temperatures from below freezing in the

winter to more than 30 degrees Celsius.winter to more than 30 degrees Celsius.

Temperate ForestsTemperate Forests Dominated by broad-leaved hardwood trees Dominated by broad-leaved hardwood trees

that loose their foliage annually, such as that loose their foliage annually, such as maple, oak, birch, elm, and ash.maple, oak, birch, elm, and ash.

Soil has a top layer that is rich in humus and a Soil has a top layer that is rich in humus and a deeper layer of clay.deeper layer of clay.

Animals include squirrels, mice, rabbits, deer, Animals include squirrels, mice, rabbits, deer, bluejays, salamanders, and bears.bluejays, salamanders, and bears.

Rain ForestsRain Forests Two types:Two types:

Tropical Rain ForestTropical Rain Forest Temperate Rain ForestTemperate Rain Forest

Found along the Olympic Peninsula in the U.S. and in Found along the Olympic Peninsula in the U.S. and in various parts of South America, New Zealand, and various parts of South America, New Zealand, and Australia.Australia.

Temperatures from 9 to 12 degrees Celsius.Temperatures from 9 to 12 degrees Celsius. Both types have extensive amounts of moisture Both types have extensive amounts of moisture

supplied by rainfall or coastal clouds and fogs.supplied by rainfall or coastal clouds and fogs. Also have the highest diversity of organisms.Also have the highest diversity of organisms.

Tropical Rain ForestTropical Rain Forest Warm temperatures, wet weather, and lush Warm temperatures, wet weather, and lush

plant growth.plant growth. Near the equator.Near the equator. Average temperature is 25 degrees Celsius.Average temperature is 25 degrees Celsius. Receive 200 to 600 cm of rain annually.Receive 200 to 600 cm of rain annually. Animals include sloths, parrots, monkeys, Animals include sloths, parrots, monkeys,

macaws, frogs, and chameleonsmacaws, frogs, and chameleons

Tropical Rain ForestTropical Rain Forest Hypothesis for abundant biodiversity:Hypothesis for abundant biodiversity:

Because they are located near the equator, tropical Because they are located near the equator, tropical rain forests were not covered by ice during the last rain forests were not covered by ice during the last ice age and thus have had more time to evolve.ice age and thus have had more time to evolve.

Tropical rain forests have year-round growing Tropical rain forests have year-round growing conditions which create a greater food supply conditions which create a greater food supply which in turn can support a greater number of which in turn can support a greater number of organisms.organisms.

Tropical rain forests provide numerous habitats Tropical rain forests provide numerous habitats and niches for diverse organisms.and niches for diverse organisms.

Tropical Rain ForestTropical Rain Forest Tropical rain forests have a large number of niches because of Tropical rain forests have a large number of niches because of

vertical layering, in which each layer, or story, have differences vertical layering, in which each layer, or story, have differences which make them suitable for different animals.which make them suitable for different animals. 3 main stories: 3 main stories:

Canopy is 25 to 45 meters high and serves as a living roof.Canopy is 25 to 45 meters high and serves as a living roof. The understory is still, humid, and dark and has inhabitants The understory is still, humid, and dark and has inhabitants

such as ferns, shrubs, insects, frogs, and snakes.such as ferns, shrubs, insects, frogs, and snakes. The ground layer is the moist forest floor where organic The ground layer is the moist forest floor where organic

material decays quickly and animals such as the jaguar roam.material decays quickly and animals such as the jaguar roam.

Tropical Rain ForestTropical Rain Forest Very few nutrients are held in the soil of rain Very few nutrients are held in the soil of rain

forests, but instead are quickly recycled forests, but instead are quickly recycled through complex food webs.through complex food webs. Hot humid climate allows ants, termites, fungi, Hot humid climate allows ants, termites, fungi,

bacteria, and other decomposers to break down bacteria, and other decomposers to break down dead plants and animals rapidly. Plants must dead plants and animals rapidly. Plants must absorb these nutrients quickly, before they are absorb these nutrients quickly, before they are washed away by rain.washed away by rain.