Properties of Communities

1
Properties of Communities Succession
2
Communities Species Diversity

• Remember a community is a group of populations
  living together is a defined area.
• Species Diversity is the number species living in
  a community (The more species living in an area,
  the higher species diversity it will have)

3
Community Stability

• Ecosystems Communities are constantly changing
  in response to natural and human disturbances
• As ecosystems change, older inhabitants gradually
  die out, while new organisms move in, causing
  additional changes to the community.
• Succession is a series of the gradual, sequential
  re-growth of a community over time
• There are 2 types of succession
• 1. Primary succession
• 2. Secondary succession

4
Primary Succession

• Primary Succession - the development of a
  community
• in an area where NO life has previously lived and
  no soil is present
• Ex The surfaces of land covered by lava or
  volcanic ash after a volcano erupts
• Ex. The bare rock exposed when glaciers melt.
• Ex. An abandoned parking lot
• Ex. Sand dune
• This process proceeds very slowly
• Minerals necessary for plant growth are
  unavailable
• Pioneer Species- the first species to populate
  the area such as lichen (small, fast
  growing/reproducing)
• Lichen is made up of a fungus and an alga and can
  grow on bare rock. When lichen die, they add
  organic materials to help form soil allowing
  plants to grow

5
Primary Succession
6
Secondary Succession

• Secondary succession takes place when some
  disturbance changes an existing community,
  WITHOUT removing the soil.
• Ex Land that has been cleared and plowed for
  farming and then is abandoned
• Ex. Wildfires
• Through the process of succession, after hundreds
  of years a more stable community may result.
  This community is referred to as the climax
  community.
• This community remains constant for along period
  of time but can still undergo change