Communities and Biomes

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Communities and Biomes
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I. Abiotic BioticInfluences

• Communities are groups of populations of
  different species.
• The environment plays a big role in how big a
  community will be.

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1. Limiting Factors

• Any biotic or abiotic factor that restricts the
  existence, numbers, reproduction, or distribution
  of organisms
• Examples
• Sunlight, Climate, Temperature, Water,
  Nutrients/Food, Fire, Soil Chemistry, Space,
  Other organisms

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2. Tolerance

• the lower and upper limits that an organism can
  survive in.
• (i.e. saltwater, temperature, oxygen levels, and
  any other limiting factors)
• A range of tolerance

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3. Succession

• Overtime communities change.
• Natural changes and species replacements in a
  community are called SUCCESSION.

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A. Primary Succession

• Colonization of new land by communities of
  pioneer species (first organisms in an area).
• Example
• After a volcanic lava flow.

http//www.countrysideinfo.co.uk/successn/primary.
htm
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B. Secondary Succession

• Colonization after a natural disaster.
• Example
• after a fire, flood, or mudslide

http//www.countrysideinfo.co.uk/successn/second.h
tm
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C. Climax Community Mature, stable community
Equilibrium has been reached. If a community is
allowed to grow to the point where it is fairly
stable, there is now, little or no change in
species. Examples sonoran desert, taiga,
rainforest
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II. Biomes

• Biomes are large groups of
• ecosystems that share
• the same type of
• climax community.
• They are the Earths
• major life zones.

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Earths Biomes
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1. Aquatic Biomes

• freshwater biome
• marine/saltwater/ocean biome

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a. Freshwater Biome

• --- low salt concentration
• usually less than 1

• Examples
• Ponds and lakes
• Streams and rivers
• Wetlands

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b. Marine Biome

• covers about ¾ of the Earth's surface
• algae supply most of our oxygen and absorb
  tons of carbon dioxide.
• Evaporation of the seawater provides
  freshwater/rainwater for the land

• Examples
• Oceans ,Coral reefs
• Estuaries

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2. Desert Biome

• covers about 1/3 of the Earth's surface
• rainfall is less than 50 cm/year
• low and high altitudes
• specialized plants and animals

• Examples
• Hot and dry
• Semiarid
• Coastal
• Cold

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3. Forest Biomes

• Tropical
• Temperate
• Taiga (Boreal)

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a. Tropical forest

• greatest species
• diversity
• only rainy and
• dry seasons
• 12 hours daylight
• always 20o-25oC

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b. Temperate forest

• Well-defined seasons
• with a distinct winter
• Moderate climate
• loose leaves annually,
• Examples oak, elm, maple
• -30 C to 30 C

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c. Taiga forest (Boreal)

• largest terrestrial biome
• short, moist, warm summers
• long, cold, and dry winters.
• mostly conifers with
• needle-like leaves
• Examples fir, spruce, and pine
• precipitation is mostly snow

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4. Grassland Biome

• Mostly grasses rather than large shrubs or trees.
• AKA prairies or savannas
• ideal for growing foods
• rain in late spring and early summer
• large temperature range/variation
• Most have been converted
• into farms and grazing lands.

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5. Tundra Biome

• coldest of all the biomes
• extremely low temperatures
• little precipitation
• very short growing seasons
• Low biotic diversity (little variety in life)
• Simple small plants/vegetation.

• Examples
• Arctic tundra - polar high latitude
• Alpine tundra high altitude -Mtns.