Lecture #2 Ecological Succession
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DESCRIPTIONLecture #2 Ecological Succession. Unit 7: Ecology. Ecological succession - the regular progression of species replacement over time in a new or disturbed community. . Succession shows some general trends that include:. 1) Biomass increases over time. - PowerPoint PPT Presentation
Lecture #2 Ecological SuccessionUnit 7: Ecology
Ecological succession- the regular progression of species replacement over time in a new or disturbed community.
1) Biomass increases over time.
2) An increase in the number & proportion of longer-lived species.
3) Increased species diversity.Succession on Mt. St. HelensSuccession shows some general trends that include:
There are two types of terrestrial succession
Primary Succession Secondary Succession
This colonization of new sites by communities of organisms takes place on bare rock Primary succession: The establishment and development of an ecosystem in an area that was previously uninhabited
New bare rock comes from 2 sourcesA volcanic lava flow cools and forms rock
This is how the Galapagos islands and the Hawaiian islands formed!
New bare rock comes from 2 sources2. Glaciers retreat and expose rock
How does the process begin? Pioneer organisms- the first organismsto colonize a new site Ex: lichens are the first to colonize lava rocks
These guys are TOUGH! They thrive where no other species can.
What do they do and what happens next ?As lichens add organic matter and form soil, mosses and other plants can colonize and grow.
As organic matter continues to accumulate, other species move in and change the environment further. First fast growing plants, then slower growing plants.
Over time, more and more species can find suitable niches and survive.
Is there an end to succession? Climax Community - a stable, maturecommunity that undergoes little or nosuccession.
** This is not necessarily a permanent community however. What would cause it to change?
Answer: A changing environment!
Secondary succession-Definition: Sequence of community changes that takes place when a community is disrupted by natural disaster or human actions
This type of succession occurs in areas where there HAD been previous growth. Because of this, the process is much faster than primary succession.
What can cause secondary succession to occur? Forest fire
The regrowth that happens after a fire levels a portion of a forest.
What can cause secondary succession to occur? 2. Abandoned Agricultural Field
Native plant life from the areas surrounding the agricultural field reinvade the area.
Case Study- Yellowstone National Park1988 Park mapshowing areas (1.6 million acres)burned by theseries of fires.
Yellowstone National Park1988 fires The immediate aftermath.
Photo: National Parks Service
Yellowstone National ParkOne year after the firesNote the appearance of fireweedPhoto: National Parks Service
Yellowstone National ParkTen years after the fires (1998) Photo: National Parks Service
Yellowstone National ParkTwenty years after the fires (2008)
Is the Yellowstone Case study an example of primary or secondary succession?
Case Study - ChernobylIn April, 1986, a nuclear power plant in the former USSR experienced a core meltdown and a catastrophic release of radioactivity into the environment.
ChernobylSurrounding towns and villages had to be immediately, permanently abandoned.
Chernobyl Twenty Years Later
Chernobyl Twenty Years LaterPripyat town square.
Chernobyl Twenty Years Later
Chernobyl Twenty Years LaterA local highway.
Is the Chernobyl Case Study an example of Primary or Secondary Succession?
Take 2 minutes to describe what succession is,and to identify the similarities anddifferences that exist between primary andsecondary succession.
Ecology*G. Podgorski, Biol. 1010*Ecology*G. Podgorski, Biol. 1010*