SuccessionSuccession

Warm UpWarm Up

1) What form does nitrogen have to be in for 1) What form does nitrogen have to be in for plants to use it?plants to use it?

2) What form does nitrogen have to be in for 2) What form does nitrogen have to be in for animals to use it?animals to use it?

3) What do plants and animals need nitrogen 3) What do plants and animals need nitrogen for?for?

4) What is the main type of organism 4) What is the main type of organism responsible for getting nitrogen into the responsible for getting nitrogen into the proper form for plants?proper form for plants?

5) Is this relationship predatory, mutualistic or 5) Is this relationship predatory, mutualistic or commensalistic?commensalistic?

A Real-life ScenarioA Real-life Scenario In 1988, a forest fire swept In 1988, a forest fire swept

through Yellowstone through Yellowstone National ParkNational Park Officials feared the worstOfficials feared the worst

Loss of animal lifeLoss of animal life Loss of plant lifeLoss of plant life Loss of tourismLoss of tourism

© Oregon Dept. of Forestry

Initially tried to stop the flames

Quickly raged out of control

A Real-life ScenarioA Real-life Scenario

Despite the initial devastation, ecologists Despite the initial devastation, ecologists were optimistic about the recovery of this were optimistic about the recovery of this national parknational park

Why be optimistic about such a Why be optimistic about such a devastating disaster?devastating disaster?

Ecologists knew about the process of Ecologists knew about the process of successionsuccession SuccessionSuccession: the gradual, sequential : the gradual, sequential

growth or regrowth of species in an growth or regrowth of species in an areaarea

Two Types of SuccessionTwo Types of Succession Primary successionPrimary succession: when : when

communities begin to develop in communities begin to develop in areas that have not previously areas that have not previously supported lifesupported life Ex: growth begins on a bare rock, on Ex: growth begins on a bare rock, on

a sand dune, on an island formed by a sand dune, on an island formed by volcanic eruption, following glacial volcanic eruption, following glacial retreat, around a newly formed pond, retreat, around a newly formed pond, etc.etc.

Primary SuccessionPrimary Succession

http://www.nodvin.net/snhu/SCI219/demos/Chapter_4/Chapter_04/Present/animations/50_2_2_1.html

Primary SuccessionPrimary Succession

1.1. Barren rock + freezing/ thawing = Barren rock + freezing/ thawing = broken rockbroken rock

2.2. Lichens colonize broken rockLichens colonize broken rock• Lichen is a Lichen is a pioneer speciespioneer species (first (first

life on the scene, usually small, life on the scene, usually small, fast-growing, and fast-producing)fast-growing, and fast-producing)

3.3. Acids in lichen + rain → wash Acids in lichen + rain → wash minerals from rockminerals from rock

4.4. Dead lichen + minerals → soil (thin Dead lichen + minerals → soil (thin layer)layer)

5.5. Grassy plants grow & die → more Grassy plants grow & die → more soilsoil

6.6. Shrubs and trees followShrubs and trees follow

LichenLichen MutualisticMutualistic association between association between

Fungi and algae orFungi and algae or Fungi and cyanobacteriaFungi and cyanobacteria

The other type of The other type of SuccessionSuccession

Secondary successionSecondary succession: when : when communities begin to re-grow communities begin to re-grow after a disruption of a prior after a disruption of a prior communitycommunity

May be a result of a natural disasterMay be a result of a natural disaster (fire, flood, volcano, earthquake, glacier, (fire, flood, volcano, earthquake, glacier, etc.etc.

May be a result of human activityMay be a result of human activity (farming, logging, mining, etc.(farming, logging, mining, etc.

Secondary SuccessionSecondary Succession

http://www.playingwithtime.org/cgi-bin/browser/gallerydisplay.pl?clipID=0120&page=3&sort=clipName&searchCriteria=

http://www.wiley.com/college/strahler/0471480533/animations/ch23_animations/animation1.html

SecondarySecondarySuccessioSuccessio

nn Faster because:Faster because: Soil already Soil already

presentpresent Seeds already Seeds already

availableavailable Most pine species of Most pine species of

a mature forest in a a mature forest in a climax community climax community cannot germinate cannot germinate without the high without the high temperatures that a temperatures that a fire producesfire produces

© Oregon Dept. of Forestry

Climax CommunityClimax Community In both cases, In both cases,

succession ends succession ends with a climax with a climax communitycommunity Stable end pointStable end point Organisms in each Organisms in each

stage prepared the stage prepared the way for organisms way for organisms in subsequent in subsequent stagesstages

Reality- more Reality- more complex, some complex, some interruptionsinterruptions

Primary or Secondary?Primary or Secondary?

Pictures taken by Rick Collins, AP Biology student. http://www.bishops.ntc.nf.ca/science/Biology/

Primary or Secondary?Primary or Secondary?

Pictures taken by Rick Collins, AP Biology student. http://www.bishops.ntc.nf.ca/science/Biology/

Must be secondary because organisms existed in area before disaster