2.3 Ecosystems are always changing

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2.3 Ecosystems are always changing

• Population size changes in response to
• food supply
• Predation
• Seasons
• birth rates

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• A limiting factor, such as water, light, or food,
  can affect population survival and growth.
• The carrying capacity of an environment is the
  maximum population it can support. At carrying
  capacity a population stops growing.

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• Ecosystems change over time.
• Succession is a gradual series of changes that
  take place in an ecosystem after a disturbance.
• There are two types of succession
• Primary
• Secondary

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• Primary - starts from an environment that is
  mostly empty of life.
• Examples - After the retreat of a glacier, for
  example, or on new rock produced by a volcano,
  life can begin to return

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• Pioneer species - 1st species that moves into
  the barren environment and begin the task of
  creating soil.
• Examples moss, lichen

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• Secondary - occurs in areas that have soil with
  roots and seeds below the surface.
• life already survives.
• may begin after a fire or flood disturbs the
  ecosystem.