Ecological SuccessionEcological Succession
Biology 1-2Biology 1-2
Ecological SuccessionEcological Succession
Ecological succession-process of biologicalcommunity change.Ecological succession-process of biologicalcommunity change.
Usually the result of a disturbance.Usually the result of a disturbance.
Also occurs when a new area opens up.Also occurs when a new area opens up.
Succession is how an area recovers after thedisturbance.Succession is how an area recovers after thedisturbance.
Succession cont’dSuccession cont’d
During succession . . .During succession . . .
Species makeup changes quickly at first.Species makeup changes quickly at first.
Size of the organisms increases.Size of the organisms increases.
Diversity increases, then stabilizes.Diversity increases, then stabilizes.
Switch from r-selected to K-selected species.Switch from r-selected to K-selected species.
Each community changes the environment,allowing succeeding communities to replace them.Each community changes the environment,allowing succeeding communities to replace them.
Primary SuccessionPrimary Succession
Primary succession-area is initially barrenand lifeless.Primary succession-area is initially barrenand lifeless.
No soil is present.No soil is present.
Occurs following volcanic eruptions or glacierretreat.Occurs following volcanic eruptions or glacierretreat.
Primary Succession cont’dPrimary Succession cont’d
The first stage of succession is called thepioneer stage.The first stage of succession is called thepioneer stage.
The first organisms are lichens and mosses.The first organisms are lichens and mosses.
Wind carries spores to the new area.Wind carries spores to the new area.
Can tolerate environments most organisms cannot.Can tolerate environments most organisms cannot.
Reproduce rapidly to overcome losses.Reproduce rapidly to overcome losses.
Prepare the area by breaking down rocks to create soil.Prepare the area by breaking down rocks to create soil.
Make the environment suitable to others.Make the environment suitable to others.
Primary Succession cont’dPrimary Succession cont’d
After the pioneer stage are the intermediatestages.After the pioneer stage are the intermediatestages.
Intermediate communities follow the pioneers.Intermediate communities follow the pioneers.
Grasses and shrubs, followed by small trees andbushes.Grasses and shrubs, followed by small trees andbushes.
Small mammals, birds, insects and reptiles movein.Small mammals, birds, insects and reptiles movein.
Primary Succession cont’dPrimary Succession cont’d
The intermediate stages lead to the climaxstage.The intermediate stages lead to the climaxstage.
The climax community is the last community toappear.The climax community is the last community toappear.
Will not change unless disturbed.Will not change unless disturbed.
Characterized by tall trees and more complexinteractions in the community.Characterized by tall trees and more complexinteractions in the community.
Primary Succession cont’dPrimary Succession cont’d
The climax community forms and maintainsequilibrium.The climax community forms and maintainsequilibrium.
K-selected species replace many r-selected species.K-selected species replace many r-selected species.
Competition, predation and symbiosis becomemore extensive.Competition, predation and symbiosis becomemore extensive.
All niches are filled.All niches are filled.
Secondary SuccessionSecondary Succession
Secondary succession The area is cleared outbut the soil is left intact.Secondary succession The area is cleared outbut the soil is left intact.
Occurs following fires, floods, human activity, etc.Occurs following fires, floods, human activity, etc.
Follows the same pattern as primary succession(pioneer to intermediate to climax).Follows the same pattern as primary succession(pioneer to intermediate to climax).
The pioneer community is weeds and grasses.The pioneer community is weeds and grasses.
Secondary succession is faster than primarysuccession.Secondary succession is faster than primarysuccession.
Lichens and mosses are not needed to create soil.Lichens and mosses are not needed to create soil.
Disturbances and RecoveryDisturbances and Recovery
Some communities are adapted to periodicdisturbances.Some communities are adapted to periodicdisturbances.
San Diego is a chaparral community.San Diego is a chaparral community.
Fire climax community.Fire climax community.
Fire clears out dead material and old growth, makingway for new growth.Fire clears out dead material and old growth, makingway for new growth.
Many native plants have adaptations for surviving.Many native plants have adaptations for surviving.
Community recovers and reaches the climax stagequickly.Community recovers and reaches the climax stagequickly.
Disturbances cont’dDisturbances cont’d
Fire prevents a more traditional climaxcommunity from forming.Fire prevents a more traditional climaxcommunity from forming.
Fire kills saplings and the seeds of trees that wouldreplace the local shrubs.Fire kills saplings and the seeds of trees that wouldreplace the local shrubs.
Trees lack adaptations to survive in theenvironment.Trees lack adaptations to survive in theenvironment.
A traditional climax community is unstable and moreopen to change.A traditional climax community is unstable and moreopen to change.