Succession

Warm Up 1) What form does nitrogen have to be in for plants to use it? 1) What form does nitrogen have to be in for plants to use it? 2) What form does nitrogen have to be in for animals to use it? 2) What form does nitrogen have to be in for animals to use it? 3) What do plants and animals need nitrogen for? 3) What do plants and animals need nitrogen for? 4) What is the main type of organism responsible for getting nitrogen into the proper form for plants? 4) What is the main type of organism responsible for getting nitrogen into the proper form for plants? 5) Is this relationship predatory, mutualistic or commensalistic? 5) Is this relationship predatory, mutualistic or commensalistic?

A Real-life Scenario In 1988, a forest fire swept through Yellowstone National Park In 1988, a forest fire swept through Yellowstone National Park Officials feared the worst Officials feared the worst Loss of animal life Loss of animal life Loss of plant life Loss of plant life Loss of tourism Loss of tourism © Oregon Dept. of Forestry Initially tried to stop the flames Quickly raged out of control

A Real-life Scenario Despite the initial devastation, ecologists were optimistic about the recovery of this national park Despite the initial devastation, ecologists were optimistic about the recovery of this national park Why be optimistic about such a devastating disaster? Why be optimistic about such a devastating disaster? Ecologists knew about the process of succession Ecologists knew about the process of succession Succession: the gradual, sequential growth or regrowth of species in an area Succession: the gradual, sequential growth or regrowth of species in an area

Two Types of Succession Primary succession: when communities begin to develop in areas that have not previously supported life Primary succession: when communities begin to develop in areas that have not previously supported life Ex: growth begins on a bare rock, on a sand dune, on an island formed by volcanic eruption, following glacial retreat, around a newly formed pond, etc. Ex: growth begins on a bare rock, on a sand dune, on an island formed by volcanic eruption, following glacial retreat, around a newly formed pond, etc.

Primary Succession

Primary Succession 1. Barren rock + freezing/ thawing = broken rock 2.Lichens colonize broken rock Lichen is a pioneer species (first life on the scene, usually small, fast-growing, and fast-producing)Lichen is a pioneer species (first life on the scene, usually small, fast-growing, and fast-producing) 3. Acids in lichen + rain → wash minerals from rock 4. Dead lichen + minerals → soil (thin layer) 5. Grassy plants grow & die → more soil 6. Shrubs and trees follow

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

The other type of Succession Secondary succession: when communities begin to re-grow after a disruption of a prior community Secondary succession: when communities begin to re-grow after a disruption of a prior community May be a result of a natural disaster (fire, flood, volcano, earthquake, glacier, etc. May be a result of a natural disaster (fire, flood, volcano, earthquake, glacier, etc. May be a result of human activity (farming, logging, mining, etc. May be a result of human activity (farming, logging, mining, etc.

Secondary Succession

Secondary Succession Faster because: Faster because: Soil already present Soil already present Seeds already available Seeds already available Most pine species of a mature forest in a climax community cannot germinate without the high temperatures that a fire produces 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

Climax Community In both cases, succession ends with a climax community In both cases, succession ends with a climax community Stable end point Stable end point Organisms in each stage prepared the way for organisms in subsequent stages Organisms in each stage prepared the way for organisms in subsequent stages Reality- more complex, some interruptions Reality- more complex, some interruptions

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

Primary or Secondary? Pictures taken by Rick Collins, AP Biology student. Must be secondary because organisms existed in area before disaster