Ecosystems

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Chapter 4

• Ecosystems
• Communities

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41 The Role of Climate

• Words you need to know
• Weather
• Climate
• The Greenhouse Effect
• Climate Zones 
• polar zones (66.5 and 90 North and South
  latitudes)
• temperate zones (between the polar
• zones and the tropics)
• tropical zone (23.5 North and 23.5
  South latitudes)

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• Heat Transport
• winds and ocean currents

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42 What Shapes an Ecosystem?

• Biotic abiotic factors
• Habitat the area where an organism lives
  (biotic and abiotic factors that affect it)
• Niche full range of physical and biological
  conditions in which an organism lives and the way
  in which the organism uses those conditions

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• no two species can share the same niche in the
  same habitat

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Community Interactions

• Competition organisms of the same or different
  species attempt to use an ecological resource in
  the same place at the same time
• Resource any necessity of life (water,
  nutrients, light, food, or space)
• competitive exclusion principle ecological rule
  that states that no two species can occupy the
  same exact niche in the same habitat at the
  same time

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• Predation interaction in which one organism
  captures (kills) and feeds on another organism 
• Predator / Prey

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• Symbiosis  Any relationship in which two species
  live closely together
• mutualism
• commensalism
• parasitism

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• Mutualism symbiotic relationship in which both
  species benefit from the relationship

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• Commensalism symbiotic relationship in which
  one member of the association benefits and the
  other is neither helped nor harmed

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• Parasitism symbiotic relationship in which one
  organism lives in or on another organism (the
  host) and consequently harms it
• Host / parasite

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Ecological Succession

• Ecosystems are constantly changing in response to
  natural and human disturbances.
• ecological succession gradual change in living
  communities that follows a disturbance

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Primary Succession 

• primary succession succession that occurs on
  surfaces where no soil exists
• Volcano
• Glacier

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• pioneer species first species to populate an
  area during primary succession
• Often lichens

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Secondary Succession 

• secondary succession succession following a
  disturbance that destroys a
  community without destroying
  the soil
• land cleared and plowed
  for farming is
  abandoned
• Wildfires

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• climax community mature, stable community that
  did not undergo further succession
• Old growth forests