Transcript What is a Biome?

Biomes
Biomes
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Scientists group ecosystems into larger
areas called biomes.
Biome: a large region characterized by a
specific type of climate and certain types of
plants and animal communities.
The World’s Major
Terrestrial Biomes
Major Biomes
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The major biomes are divided into Terrestrial
(ground) and Aquatic (water) biomes.
The aquatic biome can be divided into both Marine
(saltwater) and Freshwater biomes.
The Terrestrial Biomes are:
1) Tropical Forest
2) Temperate (Deciduous) Forest
3) Taiga (Boreal or Coniferous Forest)
4) Savannah
5) Grasslands (also called Prairie, Steppe, or Pampas)
6) Desert
7) Tundra
Further Classification
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Some biologists define more than seven terrestrial biomes,
adding Chaparral, Mountain, Island, or Tropical Dry Forest.
Biomes are often known in English by local names.
For example, a temperate grassland or shrubland
biome is known commonly as steppe in central Asia,
prairie in North America, and pampas in South
America. Tropical grasslands are known as savanna
in Australia, whereas in Southern Africa it is known
as veldt (from Afrikaans).
Biomes and Vegetation
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Biomes are described by their vegetation
because plants are the most noticeable
characteristic of a region.
The plants also determine the other organisms
that can live in an area.
Plants (& animals) in a particular biome have
adaptations that enable them to live there.
Temperature and Precipitation
1)Tropical Rain Forests
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Located in a belt around the Earth near the
equator.
Regulate world climate.
Play a vital role in the nitrogen, oxygen, and
carbon cycles.
Tropical Rain Forests
Tropical Rain Forests
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Always humid and warm
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Get 200 to 450 cm of rain a year.
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Strong sunlight year round.
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Relatively constant temperature year round.
Layers of the Rain Forest
Threats to Rain Forests
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Once covered 20% of the Earth’s surface.
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Now cover only 7% of the Earth’s surface.
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Every minute of every day, 100 acres of
tropical rain forest are destroyed.
2)Temperate Forests
Temperate Deciduous Forests
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Trees drop their broad, flat leaves each fall
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Range of temperatures can be extreme
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Growing season only lasts four to six months
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Winter temperatures often fall below freezing.
This means little water available for plants.
Temperate Deciduous Forests
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Vegetation also changes with the seasons.
Organic matter decomposes slowly in the
winter.
The soil contains more organic matter and
nutrients than the soil in a tropical rain
forest.
3) Taiga
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Northern coniferous forest (trees with cones &
needles like pine trees)
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Just below the Arctic Circle
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Winters are long (6 to 10 months)
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Average temperatures just below freezing.
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Plant growth is most abundant during the summer
because of constant daylight and more precipitation.
Taiga
Plants of the Taiga
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Conifer – tree with needle-like leaves and seeds
that develop in cones
The shape of the leaves and waxy coating
prevent them from losing too much water.
Cone-like shape prevents snow from building
up on branches and causing breakage.
Plants of the Taiga
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Needles contain substances to make the soil
acidic when the needles fall to the ground.
Most plants cannot grow in acidic soil.
Soil forms slowly because of the climate and
acidity of the soil.
A Comparison
4) Savannas
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Parts of Africa, Western India, Northern
Australia, South America
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Tropical Biome
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Dominated by grasses, shrubs, small trees
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Have a wet season and dry season
Savannas
5) Temperate Grasslands
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Large areas of the interior of continents
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Moderate rainfall but still too little for trees
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Prairies in North America, steppes in Asia,
veldt in South Africa, pampas in South
America
Temperate Grasslands
Prairie (North American Grasslands)
Steppe (Grasslands in Asia)
Veldt (Grasslands in South Africa)
Pampas (Grasslands in South America)
Plants of Temperate Grasslands
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Most fertile soil in the world
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Farmland
6) Deserts
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Widely scattered vegetation
Very little rain
In extreme cases, it never rains and there is
no vegetation
Temperature changes rapidly during a 24
hour period.
Often located near mountains that block
rain clouds.
Deserts
Deserts
7) Tundra
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Northern arctic regions
Too cold and dry for trees
Permafrost – deeper layers of soil are
permanently frozen throughout the year.
Thin topsoil
When the topsoil thaws, the land becomes
wet and spongy and is covered in bogs.
Tundra