Biomes

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 warm Equator – 30o N/S

Earth’s Atmosphere Polar regions – air is cold 60o - 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 currents 2. Earth’s rotation from west to east 3. 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

The Major Biomes 60°N 30°N

0° Equator 30°S 60°S Tropical rain forest Tropical dry forest Tropical savanna

Tundra

Temperate grassland Temperate fore Northwestern Desert coniferous fore Boreal forest Temperate woodland (Taiga) and shrubland Mountains and ice caps

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