Terrestrial Biomes

IB Syllabus: 2.4.1-2.4.2AP Syllabus

Ch 6Video – planet Earth – pole to pole

Syllabus Statements

• 2.4.1: Define the term Biome

• 2.4.2: Explain the distribution, structure and relative productivity of tropical rainforests, deserts, tundra and any other biome

vocabulary

• Biome

• Latitude

What is a biome?• World climate is variable

– Differences in temperature and precipitation– Different climates Different communities

• Biomes = Regions of the earth characterized by specific climates and community types

• Remember they cross national boundaries• Real biomes do not have sharply defined

boundaries. Ecotones = Transitional zones• Biomes not uniform, instead a mosiac of

patches– Vary in microclimate, soil types, disturbances

Dry woodlands and shrublands (chaparral)

Temperate grassland

Temperate deciduous forest

Boreal forest (taiga), evergreen coniferousforest (e.g., montane coniferous forest)

Arctic tundra (polar grasslands)

Tropical savanna,thorn forest

Tropical scrub forest

Tropical deciduous forest

Tropical rain forest,tropical evergreen forest

Desert

Ice

Mountains(complex zonation)

Semidesert,arid grassland

Tropic ofCapricorn

Equator

Tropic ofCancer

Major Terrestrial Biomes

1. Desert

2. Tundra

3. Forests1. Tropical Rainforest, Tropical deciduous forest

2. Temperate Rainforest, Temperate deciduous

3. Tiaga (Boreal)

4. Grasslands

5. Scrublands

6. Mountains

For each Biome you should comment in the distribution, climate (read

climatograms), structure, relative productivity and limiting factors

MountainIce and snow

Altitude

Tundra (herbs,lichens, mosses)

ConiferousForest

Tropical Forest

DeciduousForest

Tropical Forest

DeciduousForest

ConiferousForest

Tundra (herbs,lichens, mosses)

Polar iceand snow

Latitude

Main Biome Effects

Climate and vegetation vary in a predictable fashion with changes in Altitude and Latitude

Vegetation changes

• Plants in cold regions have traits to limit heat & water loss– Winter dormancy (drop leaves), smaller size,

evergreens have needles

• Plants in dry areas must lose heat and conserve water– No leaves, water storage, nocturnal activity

• Plants in rainforests must get light and remove water– Broad leaves, drip tips, radiate heat

mft

10

50

20

30100

Tropicalrain forest

Coniferousforest

Deciduousforest

Thornforest

Tall-grassprairie

Short-grassprairie

Desertscrub

Thornscrub

Comparison of types, sizes and stratification of species in different terrestrial biomes (structure)

Deserts1. Climate

• Precipitation < 25 cm / yr – scattered unevenly through year Arid

• May be Tropical, Temperate and Cold types – always extremes

• High to moderate insolation2. Distribution

• 30% of earth surface between 30 degrees north and south of the equator – Major ones Saraha (Africa), Gobi (Asia), Mojave (N. america)

3. Structure• Simple – very little vegetation • Most complex is temperate desert which has largest cacti

4. Relative Productivity• Low – limited by water availability

World Distribution of Deserts

Desert Types

• Tropical Deserts• High temp. year round• Little rain, only 1-2

months• Driest places on earth• Few plants• Hard windblown

surface: sand & rock• Middle East areas

Tropical desert(Saudi Arabia)

Desert Types

• Temperate Deserts• Day temp. high in

summer, low in winter• More precipitation• Sparse vegetation –

suculents, cacti, animals

• Southern CA (Mojave)

Temperate desert(Reno, Nevada)

Desert Types

• Cold deserts• Winters cold• Summers warm to hot• Precipitation low• Gobi desert, China

Polar desert(northwest China)

Plant Adaptations

Every drop of water counts1. Wax coated leaves limit

transpiration2. Deep roots tap

underground water3. Wide spread shallow

roots gather falling water4. Drop leaves & dormancy

in heat & dry periods5. Store biomass in seeds

Animal Adaptations

• Hiding in cool areas during day

• Thick skin• Dry feces,

concentrated urine• Water from dew & food• Dormancy in heat &

drought

Producer to primaryconsumer

Primaryto secondaryconsumer

Secondary tohigher-levelconsumer

All producers andconsumers todecomposers

Fungi

Gambel'squail

Red-tailed hawk

Collaredlizard

Jackrabbit

Yucca

Kangaroo ratKangaroo rat

AgaveAgave

RoadrunnerRoadrunner

Diamondback rattlesnakeDiamondback rattlesnakeDarklingbeetleDarklingbeetle

BacteriaBacteria

Pricklypearcactus

Pricklypearcactus

Human Impacts on Deserts

Large desert cities

Soil destruction by vehiclesand urban development

Soil salinization from irrigation

Depletion of undergroundwater supplies

Land disturbance and pollutionfrom mineral extraction

Storage of toxic and radioactiveWastes

Large arrays of solar cells andsolar collectors used to produceelectricity

Temperate Grasslands

1. Climate• Precipitation 25-45 cm / yr – enough to grow grass, erratic Semiarid• fire, drought, animals prevent tree growth• May be Tropical, Temperate• Moderate insolation

2. Distribution• 9% of earth surface Temperate Latitudes – Major onesNA tall grass

prairie, steppes, pampas, veldt• Grasslands overall up to 40% of earth’s surface

3. Structure• Simple – grasses and herbaceous plants

4. Relative Productivity• Medium to high – high turnover of grasses, rich soils

Polar Tundra Alpine Tundra Temperate Grassland Tropical Savanna

World Distribution of Grasslands

Temperate grassland(Lawrence, Kansas)

Grassland Types

• Temperate grasslands• Vast plains and rolling

hills• Summer hot & dry• Winter cold• Sparse, uneven

precipitation• Thick fertile soils

Producer to primaryconsumer

Primaryto secondaryconsumer

Secondary tohigher-levelconsumer

All producers andconsumers todecomposers

Fungi

Bacteria

Golden eagle

Prairiedog

Blue stemgrassBlue stemgrass

CoyoteCoyote

GrasshopperGrasshopper

GrasshoppersparrowGrasshoppersparrow

Pronghorn antelopePronghorn antelope

PrairieconeflowerPrairieconeflower

Grassland Types

• Tropical Grasslands• Savannas• High average temp• Moderate rainfall• Prolonged drought• Herds of herbivores

– Grazing & Browsing

• Africa, SA, Australia• Migrations in dry

season Tropical grassland (savanna)(Harare, Zimbabwe)

Herbivore coexistence

• Minimize competition by resource partitioning

• African animals differ by region & niche

1. Giraffes eat leaves from tree tops2. Elephants eat leaves and branches further

down3. Gazelles & Wildebeasts eat short grasses4. Zebras eat longer grass & stems

Dry Grassland Moist Grassland

Warthog Thompson'sgazelle

Waterbuck Grant's zebra

Beisa oryx

Topi

Cape buffalo Wildebeest

Dry Thorn Scrub Riverine Forest

Dik-dik East Africaneland

Blue duiker Greater kudu

Bushbuck

Black rhino

Giraffe

African elephant

Gerenuk

Human effects on Grasslands

Conversion of savanna and temperategrassland to cropland

Release of CO2 to atmosphere fromburning and conversion of grasslandto cropland

Overgrazing of tropical and temperategrasslands by livestock

Damage to fragile arctic tundraby oil production, air and water pollution,and vehicles

Tundra1. Climate

• Precipitation < 15 cm / yr – mostly snow & summer rain Arid

• Bitter cold -57 – 50 °C - permafrost• low insolation gives short growing season

2. Distribution• 60 – 75 °N latitude – northern North America, Asia,

Greenland• About 20% of the earth’s surface

3. Structure• Simple – low spongy mat of vegetation, lichens, mosses• Even trees are less than knee high

4. Relative Productivity• Low – limited by temperature and insolation

Tundra Distribution

Polar grassland (arctic tundra)(Fort Yukon, Alaska)

Tundra

• Treeless spongy mat of low growing plants

• Common breeding area b/c predators visible

• Organisms migratory• Cold & Windy & Dark• Ice & snow cover• Low precipitation but

poor drainage b/c Permafrost

Producer toprimaryconsumer

Primary to secondaryconsumer

Secondary tohigher-levelconsumer

All consumersand producers to decomposers

Lemming

Arcticfox

Horned lark

Mosquito

Grizzly bear

Long-tailed jaeger

Caribou

Willow ptarmiganWillow ptarmigan

Snowy owlSnowy owl

Dwarf willowDwarf willow

Mountain cranberryMountain cranberry

Moss campionMoss campion

Forest Types

• Undisturbed areas with moderate to high rainfall

• Dominated by various species of trees and other vegetation

• 3 main types of forest – Tropical, Temperate, Boreal

World Distribution of Forests

Temperate coniferous forests Temperate deciduous forests Tropical rain forests

Tropical Rainforest1. Climate

• Precipitation over 150 cm / yr – Wet – still rainy and dry seasons• Warm humid year round climate 80 °F • high insolation gives long growing season

2. Distribution• 23.5 °N to 23.5 °S latitude – Tropic of Capricorn to Cancer • About 2% of the earth’s surface• Three chunks – S. & C. America, C. Africa, SE Asia

3. Structure• Complex – stratified layers • High diversity - 50-80% of terrestrial species

4. Relative Productivity• Highest in terrestrial system – unlimited by temperature and insolation

Tropical rain forest(Manaus, Brazil)

Tropical Rainforest

• Tropical Rainforest• Broadleaved evergreen trees• High biological diversity,

Specialized niches, • Much of animal life found in

canopy layer• Stratification of life in different

tree layers increases niche partitioning

• Paradox high diversity but very poor soils

• Rapid recycling of nutrients• Little nutrients stay in soil

most taken back into plants• Dense forest limits wind

animal pollinators

Harpyeagle

Tocotoucan

Woolyopossum

Braziliantapir

Black-crownedantpitta

Shrublayer

Canopy

Emergentlayer

UnderstoryUnderstory

GroundlayerGroundlayer

0

5

10

15

20

25

30

35

40

45H

eigh

t (m

eter

s)

Producer to primaryconsumer

Primaryto secondaryconsumer

Secondary tohigher-levelconsumer

All producers andconsumers todecomposers

Fungi

Bacteria

Bromeliad

Ants

Tree frog

Green tree snake

Katydid

Climbingmonstera palm

Squirrelmonkeys

Blue andgold macaw

Harpyeagle

Ocelot

Slaty-tailedtrogon

Slaty-tailedtrogon

Diverse forests cleared

Replaced with monospecific stands – tree plantations

Songbird species often spend time in these areas

Top predators hunted out and displaced

Fragmentation of habitats

Temperate deciduous forest(Nashville, Tennessee)

Forests

• Temperate Forests• Significant seasonal

changes• Abundant precipitation

throughout year• Dominated by a few

broadleaved deciduous trees

• Simple structure• Thick layer of leaf litter• Once diverse, now

predators gone

Producer to primaryconsumer

Primaryto secondaryconsumer

Secondary tohigher-levelconsumer

All producers andconsumers todecomposers

Bacteria

Fungi

Wood frog

Racer

Shagbark hickory

White-taileddeer

White-footedmouse

White oak

Graysquirrel

Hairywoodpecker

Broad-wingedhawk

Long-tailedweaselLong-tailedweasel

May beetleMay beetle

MountainwinterberryMountainwinterberry

Metallic wood-boringbeetle and

Metallic wood- boring beetle and larvae

Polar evergreen coniferous forest (boreal forest, taiga)(Moscow, Russia)

Forests

• Boreal Forests (Tiaga)• Just below tundra• Dominated by coniferous

tree species– Withstand cold, rapid

growth in summer

• Low temperature– Low decomposition, high

soil acidity

• In summer soil is waterlogged = muskegs

Producer to primaryconsumer

Primaryto secondaryconsumer

Secondary tohigher-levelconsumer

All producers andconsumers todecomposers

Bacteria Bunchberry

Starflower

Fungi

Snowshoehare

Bebbwillow

Moose

Wolf

Balsam fir

Blue jay Greathornedowl

Greathornedowl

WhitespruceWhitespruce

Pine sawyer beetle and larvae

Pine sawyer beetle and larvae

MartenMarten

Clearing and degradation of tropicalforests for agriculture, livestock grazing,and timber harvesting

Clearing of temperate deciduousforests in Europe, Asia, andNorth America for timber, agriculture,and urban development

Clearing of evergreen coniferousforests in North America, Finland,Sweden, Canada, Siberia,and Russia

Conversion of diverse forests to lessbiodiverse tree plantations

Human Effects on Forests

Climatograms Review