Transcript Properties of Communities and Succession

Properties of Communities &
Succession
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)
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 regrowth of a community over time
•
There are 2 types of succession
1. Primary succession
2. Secondary succession
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
Primary Succession
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