California Science Standards #6a,b,c Ecology: Succession “Beauty for Ashes”

2 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

3 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

4 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

5 Primary Succession

6 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

7 Lichen Mutualistic association between Fungi and algae, or Fungi and cyanobacteria

8 Secondary Succession

9 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

10 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

11 Primary or Secondary? Pictures taken by Rick Collins, AP Biology student.

12 Primary or Secondary? 7/25/999/11/99 Pictures taken by Rick Collins, AP Biology student.

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