COMMUNITY ECOLOGY cont

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COMMUNITY ECOLOGY cont

• pp. 405-410

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• Species (organism)
• Population
• Community (interaction of different species)
• Ecosystem
• Biosphere

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PROPERTIES OF A COMMUNITY

• Species Richness
• Species evenness
• Species- Area Effect

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• Species Richness of different types of
  species
• varies with latitude (closer to equator the more
  species)
• more sun, better climate stability

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• Species evenness the abundance of each species

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• ?species richness and ? evenness
• ? stability (ability to withstand
• disturbances in
  the ecosystem)

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• Species- Areas Effect larger areas contain more
  species than smaller areas

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KEYSTONE SPECIES

• most dominant species in the community
• Dictates community structure
• Demonstrated by removal of keystone species from
  community

What would happen to the species richness if the
keystone species is removed from the ecosystem?
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SUCCESSION

• Sequential and gradual growth of a community
• Two types
• primary and secondary

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• Primary succession occurs when land is first
  formed.
• 1. Microbes, lichens and mosses must create
  soil before other plants can grow.
• 2. Pioneer species first species to
  dominate early in succession (small and fast
  growing)

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• Secondary succession occurs when succession must
  start over after the destruction of a climax
  community (marked by the domination of long-lived
  species and great diversity).
• - takes place on sites that have already
  supported life

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Homework

• Read pp 405-410
• P 410 1-5, 8
• Worksheet 5