Chapter 5

Chapter 5

Climate and Terrestrial Biodiversity

BIOMES: CLIMATE AND LIFE ON LAND

Different climates lead to different communities of organisms, especially vegetation.

Convection Cells

Heat and moisture are distributed over the earth’s surface by vertical currents, which form six giant convection cells at different latitudes.

Figure 5-6

Ocean Currents: Distributing Heat and Nutrients

Ocean currents influence climate by distributing heat from place to place and mixing and distributing nutrients.

Figure 5-7

Topography and Local Climate:Land Matters

Interactions between land and oceans and disruptions of airflows by mountains and cities affect local climates.

Figure 5-8

Figure 3-9


Biomes – large terrestrial regions characterized by similar climate, soil, plants, and animals.

Each biome contains many ecosystems whose communities have adapted to differences in climate, soil, and other environmental factors.


Figure 5-9

Fig. 5-9, p. 106

Polar ice

Equator

Tropic ofCapricorn

Tropic ofCancer

High mountains

Polar grassland (arctic tundra)Temperate grasslandTropical grassland (savanna)ChaparralConiferous forestTemperate deciduous forestTropical forestDesert


Biome type is determined by precipitation, temperature and soil type

Figure 5-10

Fig. 5-10, p. 107

Polar

Rain forestTropical

seasonalforest Scrubland

Savanna Desert

TropicalGrasslandChaparral

DeciduousForest

Coniferous forest

Desert

Temperate

SubpolarTundra

Wet

Cold

Dry

Hot


Parallel changes occur in vegetation type occur when we travel from the equator to the poles or from lowlands to mountaintops.

Figure 5-11

Fig. 5-11, p. 108

Mountainice and snow

Elevation

Tundra (herbs,lichens, mosses)

ConiferousForest

DeciduousForest

TropicalForest

TropicalForest

DeciduousForest

ConiferousForest

Tundra (herbs,lichens, mosses)

Polar ice and snow

Latitude

DESERT BIOMES

Deserts are areas where evaporation exceeds precipitation.

Deserts have little precipitation and little vegetation. Found in tropical, temperate and polar regions.

Desert plants have adaptations that help them stay cool and get enough water.

DESERT BIOMES

Variations in annual temperature (red) and precipitation (blue) in tropical, temperate and cold deserts.

Figure 5-12

Fig. 5-12a, p. 109

Tropical Desert

Mea

n m

onth

ly te

mpe

ratu

re (

C) M

ean monthly precipitation (m

m)

Month

Freezing point

Fig. 5-12b, p. 109

Temperate Desert

Mea

n m

onth

ly te

mpe

ratu

re (

C) M


m)

Month

Freezing point

Fig. 5-12c, p. 109

Polar Desert

Mean m

onthly precipitation (mm

)

Month

Freezing point

Mea

n m

onth

ly te

mpe

ratu

re (°

C)

DESERT BIOMES

The flora and fauna in desert ecosystems adapt to their environment through their behavior and physiology.

Figure 5-13

Fig. 5-13, p. 110

Producer to primaryconsumer

Primaryto

secondaryconsumer

Secondary to

higher-levelconsumer

All producers andconsumers todecomposers

Kangaroo rat

Diamondback rattlesnake Fungi

Bacteria

DarklingBeetle

Roadrunner

Pricklypearcactus

Agave

Gambel'sQuail

Collaredlizard

Jackrabbit

Yucca

Red-tailed hawk

GRASSLANDS AND CHAPARRAL BIOMES

Variations in annual temperature (red) and precipitation (blue).

Figure 5-14

Fig. 5-14a, p. 112

Tropical grassland (savanna)

Mea

n m

onth

ly te

mpe

ratu

re (

C) M


m)

Month

Freezing point

Fig. 5-14b, p. 112

Temperate grassland

Mea

n m

onth

ly te

mpe

ratu

re (

C) M


m)

Month

Freezing point

Fig. 5-14c, p. 112

Polar grassland (arctic tundra)

Mea

n m

onth

ly te

mpe

ratu

re (

C) M


m)

Month

Freezing point

GRASSLANDS AND CHAPARRAL BIOMES

Grasslands (prairies) occur in areas too moist for desert and too dry for forests.

Savannas are tropical grasslands with scattered tree and herds of hoofed animals.

Temperate Grasslands: Prairies

The cold winters and hot dry summers have deep and fertile soil that make them ideal for growing crops and grazing cattle.

Figure 5-15

Temperate Grasslands Temperate tall-

grass prairie ecosystem in North America.

Accumulated organic matter create deep, fertile

Figure 5-16

Polar Grasslands Polar

grasslands are covered with ice and snow except during a brief summer.

Very fragile, recovers slowly from damage

Tundra (polar grasslands)Covers 10% of earth’s land. Most of the

year, these treeless plains are bitterly cold with ice & snow. It has a 6 to 8 week summer w/ sunlight nearly 24 hours a day.

Chaparral (temperate grassland)

These are coastal areas. Winters are mild & wet, w/ summers being long, hot, & dry.

Chaparral Chaparral has a

moderate climate but its dense thickets of spiny shrubs are subject to periodic fires.

Higher rainfall in winter season creates greater risk of fire in dry summer season …more biomass. Ex: CA fires

FOREST BIOMES

Variations in annual temperature (red) and precipitation (blue) in tropical, temperate, and polar forests.

Figure 5-19

Fig. 5-19a, p. 116

Tropical rain forest

Mea

n m

onth

ly te

mpe

ratu

re (

C) M


m)Month

Freezing point

Fig. 5-19b, p. 116

Temperate deciduous forest

Mea

n m

onth

ly te

mpe

ratu

re (

C) M


m)Month

Freezing point

Fig. 5-19c, p. 116

Polar evergreen coniferous forest(boreal forest, taiga)

Mea

n m

onth

ly te

mpe

ratu

re (

C) M


m)

Month

Freezing point

FOREST BIOMES

Forests have enough precipitation to support stands of trees and are found in tropical, temperate, and polar regions.

Tropical Rain Forest

Tropical rain forests have heavy rainfall and a rich diversity of species. Found near the

equator. Have year-round

uniformity warm temperatures and high humidity.

Figure 5-20


Filling such niches enables species to avoid or minimize competition and coexist

Figure 5-21

Fig. 5-21, p. 118

GroundlayerBlack-crowned

antipitta

Brazilian tapir

Woolly opossum

Tocotoucan

Shrublayer

Understory

Canopy

Emergent layer

Hei

ght (

met

ers)

Harpy eagle


Very high diversity Rapid recycling of nutrients: decompose

quickly, nutrients are taken up by plants Soil is acidic and nutrient poor Slash & burn: land can only support crops or

cattle for a year or two: heavy rains leach out remaining nutrients

Rapidly losing remaining acres

Temperate Deciduous Forest

Most of the trees survive winter by dropping their leaves, which decay and produce a nutrient-rich soil.

Figure 5-22

Evergreen Coniferous Forests (Taiga)

Consist mostly of cone-bearing evergreen trees that keep their needles year-round to help the trees survive long and cold winters.

Figure 5-23

Temperate Rain Forests

Coastal areas support huge cone-bearing evergreen trees such as redwoods and Douglas fir in a cool moist environment.

Figure 5-24

MOUNTAIN BIOMES High-elevation islands of

biodiversity Cover ¼ of land surface Dramatic changes in soil,

climate, plants over short distances

Help regulate climate: snow-covered peaks reflect solar radiation

Water cycle: Glacier ice, gradually release water to lower-elevation streams and ecosystems.

Figure 5-25

HUMAN IMPACTS ON TERRESTRIAL BIOMES

Human activities have damaged or disturbed more than half of the world’s terrestrial ecosystems.

Humans have had a number of specific harmful effects on the world’s deserts, grasslands, forests, and mountains.

Fig. 5-26, p. 123

Natural Capital Degradation

Desert

Large desert cities

Soil destruction by off-road vehicles

Soil salinization from irrigation

Depletion of groundwater

Land disturbance and pollution from mineral extraction

Fig. 5-27, p. 123

Oil production and off-road vehicles in arctic tundra

Overgrazing by livestock

Release of CO2 to atmosphere from grassland burning

Conversion to cropland

Grasslands


Fig. 5-28, p. 124

Clearing for agriculture, livestock grazing, timber, and urban development

Conversion of diverse forests to tree plantations

Damage from off-road vehicles


Forests

Pollution of forest streams

Fig. 5-29, p. 124


Mountains

Agriculture

Timber extraction

Mineral extraction

Hydroelectric dams and reservoirsIncreasing tourism

Urban air pollution

Increased ultraviolet radiationfrom ozone depletion

Soil damage from off-roadvehicles

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