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Section 03.2
Terrestrial Biomes
Objectives
• Relate latitude and the three major climate zones.
• Describe the major abiotic factors that determine the location of a terrestrial biome.
• Distinguish among terrestrial biomes based on climate and biotic factors.
Main Idea
• Ecosystems on land are grouped into biomes primarily based on the plant communities within
them
Latitude and Climate
• Weather
◦ = is the condition of the atmosphere at a specific place and time
◦ what causes the variation in the Earth’s weather patterns?
◦ how does weather effect communities on the Earth?
◦ one of the keys to both of these questions
 is to be aware of latitude
• Latitude
◦ = the distance of any point on the surface of Earth north or south from the equator
 the greater the latitude
□ the further from the equator
~ sunlight strikes the Earth less directly

◦
hence, Earth’s surface heated differently
results in three climate zones
 polar
 temperate
 tropical
• Climate
◦ = the average weather conditions in an area
 including temperature and precipitation
◦
greatly affected by the area’s latitude
 not the only factor
 examples
□ elevation
□ continental landmass
□ ocean currents
◦
climate effects the type of biome
Major Land Biomes
• Biomes are classified
◦ primarily according to the characteristics of its
 plants
◦
◦
secondarily, according to its
 temperature
 precipitation
◦
animals also are important characteristics of biomes
Major land biomes include
◦ Tundra
◦ Boreal forest
◦ Temperate forest
◦ Temperate woodland and shrubland
◦ Temperate grassland
◦ Desert
◦ Tropical savanna
◦ Tropical seasonal forest
◦ Tropical rain forest
• Tundra
◦ generally found south of the polar ice cap
 of North America
◦
= treeless biome with a layer of permafrost
 permafrost
□ = a layer of permanently frozen soil below the soil’s surface

prevents the growth of tree roots

Boreal Forest
 aka
 Northern coniferous forest
 Taiga
 located south of the tundra
 = a broad band of dense evergreen forest
 extends across North America, Europe, Asia
 compared with tundra, its summers are
 longer
 warmer

Temperate Forest
 covers much of
 southeastern Canada
 eastern U. S.
 most of Europe
 parts of Asia and Australia

composed mostly of deciduous trees
 = trees that shed their leaves in autumn

climate
 winters are cold
 summers are hot
 springs are warm and precipitation
 restart the growth cycle of plants
• Temperate woodland and shrubland
◦ have less rainfall than temperate forests
◦ occurs in areas
 surrounding the Mediterranean Sea
 on the west coast of N. & S. America
 of South Africa and Australia
◦
◦
area is dominated by shrubs
 ex: California’s chaparral
Temperate grassland
◦ = biome with fertile soils that support a thick cover of grasses
◦ kept from becoming forests by
 drought
 grazing animals
 fires
◦
this biome located in
 North America – prairies
 South America – pampas
 Asia – steppes
 Africa – savannahs
 Australia – rangelands
• Desert
◦ = area in which the annual rate of evaporation
 exceeds the rate of precipitation
◦
occur on every continent except Europe
◦
temperatures vary greatly
 quite hot during the day
 fairly cold at night
• Tropical savanna
◦ characterized by
 grasses
 scattered trees
 less precipitation than other tropical areas
◦
occur in
 Africa
 South America
 Australia
• Tropical seasonal forests
◦ aka tropical dry forests
◦ located in areas of
 Africa, Asia, Australia, South and Central America
◦
resembles the deciduous forests
 because during dry season
□ trees lose their leaves
□ to conserve water
• Tropical rain forests
◦ characterized by
 warm temperatures
 large amounts of precipitation
◦
found in
 Central & South America, southern Asia, western Africa, and NE Australia
◦
most diverse of all biomes
 supports more different forms of life
Other Terrestrial Areas
• Mountains
◦ inc elevation causes changes in
 abiotic factors
□ temperature
□ precipitation


communities
□ tops of tall mountains resemble tundra
Polar regions
 not considered biomes because
 are ice masses
 not true land masses with soil



have higher latitudes than tundra
are cold year-round
northern polar region
 ice-covered Arctic Ocean
 Greenland

southern polar region
 Antarctica