Download ECOLOGICAL SUCCESSION

ECOLOGICAL SUCCESSION
Community is all the different organisms that live together in an area. That
community is in Equilibrium (or, a state of balance) when the species of organisms
in it do not change suddenly. Sometimes a community's equilibrium is disrupted,
changing it drastically in a very short time. Now, the community is NOT in a state
of equilibrium/balance.
What types of things would "disrupt" the balance of a community?
Wild Fires
Floods
Volcanoes
Hurricanes
Tsunamis
Earthquakes
Tornadoes
Lightning
Avalanches
...Not all disruptions are natural.
Some are due to human impact:
Farming
Mining
Logging
Etc.
What happens next?  Succession. Succession is the series of predictable
changes that occur in a community over time. Succession enables an ecosystem to
rebuild after a disruption in the equilibrium.
Two types of Succession:
1- Primary and 2- Secondary
1- Primary Succession:
Occurs in an area where no ecosystem previously existed; in
other words, it's starting from scratch. Examples:
-An area of rock uncovered by a melting sheet of ice.
-A new island formed by the eruption of an undersea volcano.
-After a volcano erupts- there's NO soil, just ash & rock.
-The 1st species to populate the area: Pioneer Species.
-Pioneer Species are often Lichens & Mosses carried to
the area by wind or water.
-These can grow on bare rocks with little or no soil.
-As they grow, they break up the rocks and form soil.
-When they die, they decompose & enrich the thin layer
of soil that is forming.
-Over time, new plant seeds land in the new soil and
grow.
-The types of plants that can grow depend on the biome.
Eventually, Primary Succession leads to a Climax Community in
equilibrium, which does not drastically change unless the ecosystem is
disrupted. A Climax Community is a community that has reached a
stable stage of ecological succession; it is a combination of plants and
animals that use available resources most efficiently. This entire
process can take centuries.
2- Secondary Succession:
Secondary Succession occurs after a disruption in an existing ecosystem.
Unlike primary succession, Secondary Succession occurs more rapidly.