California Science Standards #6a,b,c
Ecology: Succession
“Beauty for Ashes”
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Fire Bad In 1988, a forest fire swept through
Yellowstone National Park Officials feared the worst
Loss of animal life Loss of plant life Loss of tourism
© Oregon Dept. of Forestry Initially tried to stop the
flames Quickly raged out of control
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Fire Bad … or is it? Despite the initial devastation, ecologists
were optimistic about the recovery of this national park
Why? Succession =
The gradual, sequential re-growth of species in an area
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Two Types Primary Succession-
No life there previously Secondary Succession
Community was disrupted by Natural disaster
Fire, storm, earthquake, flood, volcano, glacier, etc.
Human activity Farming, logging, mining
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Primary Succession
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Primary Succession Slower of the two
Need minerals for plants to grow Barren rock + freezing/ thawing = broken rock lichens colonize broken rock
Lichen is a pioneer species (first life on the scene)
Acids in lichen + rain = wash minerals from rock Dead lichen + minerals = soil (thin layer) Grassy plants grow & die = more soil Shrubs and trees follow
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Lichen Mutualistic association between
Fungi and algae, or Fungi and cyanobacteria
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Secondary Succession
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SecondarySuccession
Faster because Soil already present Seeds already
available And, most pine species
of a mature forest in a climax community cannot germinate without the high temperatures that a fire produces
© Oregon Dept. of Forestry
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Climax Community In both cases,
succession “ended” with a climax community Stable end point Organisms in each
stage prepared the way for organisms in subsequent stages
Reality- more complex, dynamic Interruptions
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Primary or Secondary?
Pictures taken by Rick Collins, AP Biology student. http://www.bishops.ntc.nf.ca/science/Biology/
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Primary or Secondary?
7/25/99 9/11/99
Pictures taken by Rick Collins, AP Biology student. http://www.bishops.ntc.nf.ca/science/Biology/
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