Climate and Terrestrial Biodiversity

Chapter 7

7.1

The Earth Has Many Different Climates

Weather – local area’s short-term temperature, precipitation, humidity, wind speed, cloud cover, etc.• Measured over

hours or days

The Earth Has Many Different Climates

Climate – area’s general pattern of atmospheric or weather conditions• Measured over

long periods of time

The Earth Has Many Different Climates

Climate - varies over different parts of the earth• Uneven heating of

the earth’s surface by the sun

• Rotation of the earth on its axis

• Properties of air, water, and land

Earth’s Atmosphere

Tropics – air is warmEquator – 30o N/S

Earth’s Atmosphere

Polar regions – air is cold60o - 90o N/S

Convection Currents

Up-and-down movement of air due to temperature differences

Convection Currents

Rule: Hot air rises and cold air sinks.

Equator• Hot air rises and heads toward the poles

Convection Currents

Rule: Hot air rises and cold air sinks.

Poles• Cold air rushes in to fill the space at the

equator

Figure 6.5

Wind

Horizontal movement of air

Convection Currents + Earth’s Rotation

Equator

Coriolis Effect

Earth rotates and causes circulating air to be deflected

Causes things thrown in straight line to move to the right or left (depends on hemisphere)

Imagine a merry-go-round…

Suppose you (represented by the dark blue circle) and a friend (represented by light blue circle) are on a merry go round.

You gently toss a ball towards your friend

The ball doesn’t actually get there!

Coriolis Effect Summary

Causes moving objects on Earth to follow curved paths• Northern Hemisphere – follows a path to

the right of its intended target• Southern Hemisphere – follows a path to

the left of its intended target Acts on all moving objects

Your Turn!

Deflected Activity Global Wind Patterns

Prevailing Winds

Major wind patterns on the Earth

Direction caused by:1. Convection currents2. Earth’s rotation from west to east3. Air pressure

Global Air Circulation

Wind Belts

Doldrums• Between 5

degrees North and 5 degrees South latitude

• Winds are calm

Wind Belts

Trade Winds • Historically: Used

by ships traveling between Europe and the Americas

• 5o-30o North and South of the Equator

Trade Winds

Northern Hemisphere• Warm air around

the equator rises and flows north toward the pole• Earth’s rotation

deflects air toward the right

Trade Winds

Southern Hemisphere• Similar pattern• Winds blow from

the southeast toward the northwest

• Descend near 30 degrees South latitude

Wind Belts

Westerly Winds • Remaining air (air

that does not descend at 30 degrees North or South latitude) continues toward the poles

Wind Belts

Polar Easterlies• Cool air sinks and

moves towards the equator

• Air is deflected by Earth’s rotation

Winds Drive Surface Ocean Currents!

Global winds drag on the water’s surface• Cause water to

move and build up in the direction that the wind is blowing

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

Your Turn!

Coastal Upwelling

Climate and Biomes

Biotic and Abiotic Factors

Biotic Factors• Biological (living)

influences on an organism within an ecosystem• Predators• Prey

Abiotic Factors• Physical (non-living)

factors that shape ecosystems• Temperature• Precipitation• Humidity

What is a biome?

Terrestrial community that covers a large area and is characterized by certain soil and climate conditions • Particular assemblages of plants and animals.

Biomes

Variations in plants and animals help different species survive under different conditions in different biomes.

Tolerance - ability to survive and reproduce under conditions that differ from their optimal conditions

Tropical rain forest

Tropical dry forest

Tropical savanna

Tundra

Temperate grassland

Desert

Temperate woodlandand shrublandMountains and ice caps

Boreal forest(Taiga)

Northwesternconiferous forest

Temperate forest

60°N

30°S

0° Equator

60°S

30°N

The Major Biomes

Biomes

Large terrestrial regions characterized by similar climate, soil, plants, and animals• Location irrelevant

Biomes

Not uniform; consist of a mosaic of patches with different biological communities

Generalized Effects of Elevation and Latitude on Climate and Biomes

Natural Capital: Average Precipitation and Average Temperature as Limiting Factors

Your Turn!

Biome Jigsaw Biome Bags

Global Air Circulation, Ocean Currents, and Biomes

Energy Transfer by Convection in the Atmosphere

Heat is absorbed and released more slowly by water than by land• Moderate weather

and climate of nearby lands

Biomes and Climate

The climate of a region is an important factor in determining which organisms can survive there. • Temperature and precipitation

can vary over small distances.• Microclimate - the climate in a

small area that differs from the climate around it

The Earth’s Surface Features Affect Local Climates

Cities• Microclimates

• More haze and smog• Higher temperatures• Lower wind speeds

• Causes • Bricks, asphalt, and

concrete absorb and hold heat

• Buildings block wind flow

The Earth’s Surface Features Affect Local Climates

Mountains• Rain shadow effect: moist air blowing inland is forced

upward; cools and expands• Loses most of its moisture as rain or snow on the

windward slope• Air dries and warms over leeward side; increases

ability to hold moisture and dries ecosystem

Climate Terms

Tropical – warm; receives direct or nearly direct sunlight year round

Desert - dry Temperate – moderate

Climate Graphs of Three Types of Deserts

Climate Graphs of Tropical, Temperate, and Cold Grasslands

Chaparral Vegetation in Utah, U.S.

Climate Graphs of Tropical, Temperate, and Cold Forests

Stratification of Specialized Plant and Animal Niches in a Tropical Rain Forest

Major Human Impacts on Terrestrial Ecosystems

Tundra

Taiga

See Clip

Tropical Rain Forest

Temperate Forest

Temperate Grassland

Desert

Chaparral