Different Climates Support Different Life Forms

• Climate – decade/century long temperature and precipitation patterns – determines which plants and animals can live where

• Tropical: equator, intense sunlight

• Polar: poles, little sunlight

• Temperate: in-betweentropical and polar

Three Major Climate Zones

Fig. 7-1, p. 147

Tropical

Polar

Temperate

Weather Vs. Climate• Weather • Temperature, precipitation, wind speed, cloud cover• Timeframe: Hours to days

• Climate• Area’s general pattern of atmospheric conditions over

decades and longer• Timeframe: Decades to centuries

Fig. 7-2, p. 149

Natural Capital: Generalized Map of the Earth’s Current Climate Zones

Major Drivers of Climate• Wind Patterns (air circulation in lower atmosphere)

• Due to:1. Uneven heating of the earth’s surface by sun2. Earth’s rotation3. Heat absorbing properties of air, water, and land

• Ocean currents • Due to:1. Prevailing winds 2. Earth’s rotation 3. Ocean temperature4. Ocean salinity

Fig. 7-3, p. 149

Global Air Circulation

Fig. 7-4, p. 150

Energy Transfer by Convection in the Atmosphere

Fig. 7-5, p. 150

Connected Deep and Shallow Ocean Currents

Major Driver of Climate• Greenhouse gases• H2O

• CO2

• CH4

• N2O

• Natural greenhouse effect• Gases keep earth habitable

• Human-enhanced global warming

Local Climates or Micro-Climates

• Uneven heat absorption by land and water• Land and sea breezes

• Elevation• Rain shadow effect• Most precipitation falls on the windward side of

mountain ranges• Deserts leeward

• Cities create microclimates

Fig. 7-8, p. 153

Generalized Effects of Elevation and Latitude on Climate and Biomes

Fig. 7-6, p. 152

Rain Shadow Effect

Climate Helps Create Biomes

• Major biomes: large land regions with certain types of climate and dominant plant life

• Created by/Controlled by• Latitude and elevation• Annual precipitation• Temperature

Fig. 7-7, p. 153

The Earth’s Major Biomes

Figure 3, Supplement 8

North America Biomes

Figure 6, Supplement 8

Global Plant Biodiversity

There Are Three Major Types of Deserts

1. Tropical deserts

2. Temperate deserts

3. Cold deserts

• All 3: Fragile ecosystem• Slow plant growth• Low species diversity• Slow nutrient recycling• Lack of water

Fig. 7-10, p. 155

Climate Graphs of Three Types of Deserts

Fig. 7-A, p. 156

Wildflowers Bloom after Rain in Arizona

There Are Three Major Types of Grasslands

1. Tropical• Savanna: Mostly grassland with scattered trees• Wet and Dry seasons

1. Temperate• Cold winters and hot and dry summers• Grass prairies• Often converted to farmland

There Are Three Major Types of Grasslands

3. Cold (arctic tundra)• Plants close to ground to conserve heat• Most growth in short summer• Permafrost: Underground soil that stays frozen

Fig. 7-11, p. 157

Climate Graphs of Tropical, Temperate, and Cold Grasslands

Fig. 7-12, p. 158

Monoculture Crop Replacing Biologically Diverse Temperate Grassland

Temperate Shrubland: Nice Climate, Risky Place to Live

• Chaparral

• Near the sea: nice climate

• Prone to fires in the dry season

There Are Three Major Types of Forests

1. Tropical• High temperature and precipitation• Very High Species Diversity• Rapid recycling of scarce soil nutrients• Rapidly impacted by human activities

2. Temperate• Diversity of broad-leaf, deciduous trees• Moderate Rainfall

There Are Three Major Types of Forests

3. Cold• Evergreen coniferous forests: boreal or taigas• Cold and drier climate• Low cone bearing tree diversity

• Other types of forests:• Coastal coniferous forest (on both North American

coasts)• Temperate rain forests (Oregon)

Fig. 7-13, p. 160

Climate Graphs of Tropical, Temperate, and Cold Forests

Fig. 7-16, p. 163

Temperate Rain Forest in Washington State

Mountains Play Important Ecological Roles

• Majority of the world’s forests

• Islands of biodiversity

• Habitats for endemic species

• Help regulate the earth’s climate

• Major storehouses of water (snowpack and glaciers)• Role in hydrologic cycle

Fig. 7-17, p. 163

Mount Rainier National Park in Washington State

7-3 How Have We Affected the Word’s Terrestrial Ecosystems?

• Concept 7-3 In many areas, human activities are impairing ecological and economic services provided by the earth’s deserts, grasslands, forests, and mountains.

Common Human Impacts to Biomes• Deserts• Large desert cities• Destruction of soil and underground habitat by

off-road vehicles• Soil salinization from irrigation• Depletion of groundwater• Land disturbance and pollution from mineral

extraction

Common Human Impacts to Biomes• Grasslands• Conversion to cropland• Release of CO2 to atmosphere from burning

grassland• Overgrazing by livestock• Oil production and off-road vehicles in arctic

tundra

Common Human Impacts to Biomes• Forests• Clearing for agriculture, livestock grazing, timber,

and urban development• Conversion of diverse forests to tree plantations• Pollution of forest streams

Common Human Impacts to Biomes• Mountains• Timber and mineral extraction• Hydroelectric dams and reservoirs• Air pollution blowing in from urban areas and

power plants• Water supplies threatened by glacial melting• Increasing tourism

Three Big Ideas

1. Differences in climate, based mostly on long-term differences in average temperature and precipitation, largely determine the types and locations of the earth’s deserts, grasslands, and forests.

2. The earth’s terrestrial systems provide important ecological and economic services.

Three Big Ideas

3. Human activities are degrading and disrupting many of the ecological and economic services provided by the earth’s terrestrial ecosystems.