Ecology Part 2 Chapter 3 Communities

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Ecology - Part 2 Chapter 3Communities Biomes
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I. Abiotic Influences

• A. Communities are groups of populations of
  different species.
• However the environment plays a big role in how
  big a community can become.

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Abiotic Influences

• Food, water, temperature, and others can all
  limit a communitys ability to survive.
• Therefore these are called Limiting Factors
• If there is a lot a food in an area, but no water
  what will happen to the community?

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1. Limiting Factors

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

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2. Tolerance

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

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3. Succession

• Overtime communities change.
• Natural changes and species replacements in a
  community are called Succession.
• Orderly natural changes and species replacements
• Two Types
• Succession primary or secondary

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A. Primary Succession

• Colonization of a new site (barren land) by
  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

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http//www.countrysideinfo.co.uk/successn/second.h
tm
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Climax Community.

• Climax Community
• Mature, stable community Equilibrium reached
• There is now little or no change in species

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II. Biomes

• Biome is a large group 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

• Ponds and lakes
• Streams and rivers
• Wetlands

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b. Marine Biome

• covers about ¾s of the Earth's surface
• algae supply most oxygen and absorb tons of
  atmospheric carbon dioxide.
• The evaporation of the seawater provides
  rainwater for the land

• Oceans
• Coral reefs
• Estuaries

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2. Desert Biome

• covers about 1/5 of the Earth's surface
• rainfall is less than 50 cm/year
• low and high altitudes
• specialized plants and animals

• 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 to 25o C

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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

• 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
• 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
• short growing seasons
• Low biotic diversity
• Simple vegetative structure

• Arctic tundra
• Alpine tundra