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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